research article on insomnia

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We are finally waking up to the causes of insomnia and how to treat it

Millions of people struggle with insomnia, but the sleep disorder is now a solvable problem – and the most effective therapy might involve your smartphone rather than sleeping pills

By David Robson

28 September 2022

How do people fall asleep? I’m afraid I’ve lost the knack,” muses the unnamed protagonist in Dorothy Parker’s 1933 short story The Little Hours. “Early to bed, and you’ll wish you were dead. Bed before eleven, nuts before seven.”

You will almost certainly relate to this frustration if you have ever found it difficult to nod off. The more you try to create the right conditions for sleep, the more elusive it appears; the very desire makes it impossible to achieve. Parker’s character experienced such angst from her unwanted wakefulness that she considered “busting [myself] over the temple with a night-light”.

That may be a familiar feeling for many: insomnia is a common condition. It is also one that has far-reaching health and economic impacts. Yet, for decades, scientists had struggled to offer a good solution. But an explosion in sleep research over the past few years has helped to identify the neurological and mental processes underlying it. This deeper understanding of how the brain can cause this debilitating condition means we have reached a turning point in its treatment.

Simply put, we are now in a much better position to work out why someone has trouble sleeping – and the best way to bring them the rest they so desperately seek. “Insomnia is a solvable problem,” says Colin Espie at the University of Oxford.

That will be sweet music to many ears. The chances are that either you, or someone very close to you, could directly benefit from this new knowledge, given how prevalent insomnia is. According to various surveys, a third of people…

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ORIGINAL RESEARCH article

The different faces of insomnia.

• 1 Department of Internal Medicine and Dermatology, Interdisciplinary Center of Sleep Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
• 2 Department of Behavioral Therapy and Psychosomatic Medicine, Rehabilitation Center Seehof, Federal German Pension Agency, Seehof, Germany
• 3 Department of Biology, Saratov State University, Saratov, Russia

Objectives: The identification of clinically relevant subtypes of insomnia is important. Including a comprehensive literature review, this study also introduces new phenotypical relevant parameters by describing a specific insomnia cohort.

Methods: Patients visiting the sleep center and indicating self-reported signs of insomnia were examined by a sleep specialist who confirmed an insomnia diagnosis. A 14-item insomnia questionnaire on symptoms, progression, sleep history and treatment, was part of the clinical routine.

Results: A cohort of 456 insomnia patients was described (56% women, mean age 52 ± 16 years). They had suffered from symptoms for about 12 ± 11 years before seeing a sleep specialist. About 40–50% mentioned a trigger (most frequently psychological triggers), a history of being bad sleepers to begin with, a family history of sleep problems, and a negative progression of insomnia. Over one third were not able to fall asleep during the day. SMI (sleep maintenance insomnia) symptoms were most frequent, but only prevalence of EMA (early morning awakening) symptoms significantly increased from 40 to 45% over time. Alternative non-medical treatments were effective in fewer than 10% of cases.

Conclusion: Our specific cohort displayed a long history of suffering and the sleep specialist is usually not the first point of contact. We aimed to describe specific characteristics of insomnia with a simple questionnaire, containing questions (e.g., ability to fall asleep during the day, effects of non-medical therapy methods, symptom stability) not yet commonly asked and of unknown clinical relevance as yet. We suggest adding them to anamnesis to help differentiate the severity of insomnia and initiate further research, leading to a better understanding of the severity of insomnia and individualized therapy. This study is part of a specific Research Topic introduced by Frontiers on the heterogeneity of insomnia and its comorbidity and will hopefully inspire more research in this area.

Introduction

Insomnia is one of the most frequent sleep disorders with continuously increasing prevalence. About 30–50% of the US adult population exhibit insomnia symptoms, 15–20% display a short-term insomnia of <3 months, and 5–15% display a chronic insomnia of >3 months ( 1 – 3 ). Common diagnostic manuals include the ICSD-3 (International Classification of Sleep Disorders, 3 rd Edition, American Academy of Sleep Medicine 2014) and the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5 th Edition, American Psychiatric Association 2013) ( 4 , 5 ). Main characteristics of insomnia include dissatisfaction with sleep quantity and quality with one or more of the following symptoms: difficulties initiating sleep, difficulties maintaining sleep (frequent or prolonged awakenings with problems returning to sleep again), and early morning awakening (occurring earlier than desired after a total sleep time of only 3–5 h with the inability to return to sleep). The disturbed sleep is associated with stress, psychological strain and suffering, as well as impairment in social, occupational, and other important areas of functioning. Complaints include fatigue, exhaustion, lack of energy, daytime sleepiness, cognitive impairment (e.g., attention, concentration, and memory), mood swings (e.g., irritability, dysphoria), impaired occupational functioning and impaired social functioning. The symptoms occur for at least 3 nights per week for at least 3 months and occur despite an adequate sleep environment.

Previous dichotomization of insomnia in primary and secondary (or comorbid) insomnia has been abandoned with the new editions of the DSM-5 and ICSD-3. Currently, insomnia is mostly characterized by the common phenotypes of sleep onset insomnia (SOI insomnia, difficulty falling asleep), sleep maintenance insomnia (SMI insomnia, difficulty staying asleep), early morning awakenings insomnia (EMA insomnia), and a combination of those. Another categorization follows the timeframe of being an acute (<1 month), subacute (1–3 months), and chronic insomnia (>3 months) ( 4 , 5 ). While other sleep disorders (e.g., sleep apnea) are categorized by severity into mild, moderate, or severe, which has important implications for the choice of therapy, insomnia still lacks such a classification. The Insomnia Severity Index (ISI) is the only instrument currently in use that allows for severity classification: no insomnia (score 0–7), subclinical insomnia (score 8–14), or moderate to severe insomnia (score 15–28) ( 6 ).

The characterization of different phenotypes is important to establish clinically relevant subtypes of insomnia. It may help to reduce the heterogeneity of insomnia and facilitate cause identification and personalized treatments. Yet there are not many standardized instruments of insomnia diagnosis allowing for phenotyping. However, there has been evidence that insomniacs with a total sleep time of <6 h suffer a more severe insomnia than insomniacs with a total sleep time of 6 h or more ( 7 ). They display mental and psychological impairment compared to patients with average or longer than average sleep. However, mortality is increased for insomniacs with longer total sleep time ( 8 ). The sleep duration with the 6-h distinction also influences the therapy outcome, success of cognitive-behavioral therapy (CBT), and the relation to comorbid bipolar disorder ( 9 , 10 ). Recently, a study investigated subtypes of insomnia according to psychological stress ( 11 ). Questioning 2,224 volunteers with an ISI score of at least 10 and a control group of 2,098 volunteers with an ISI score below 10, five insomnia subtypes were identified: highly distressed, moderately distressed but sensitive to positive reinforcement (accepting of positive emotions), moderately distressed insensitive to positive reinforcement, slightly distressed with a high reactivity to their environment and life circumstances, and slightly distressed with low reactivity. The results showed a high stability of the classification over the 5-year investigation. The psychological categorization is clinically relevant as there were clear differences identified between the subtypes regarding development, therapy success, presence of electroencephalogram (EEG) biomarker, and the risk for depression. This was a first approach to subtyping insomnia patients according to psychological health. The exact effect of psychological health, family history, comorbidity, personality, environment and sleep quality on insomnia is still unclear. Similar symptom clusters have been discussed for other disorders including depression ( 12 ).

Our study is part of the specific Research Topic introduced by Frontiers on the heterogeneity of insomnia and its comorbidity. We aim to encourage and further the discussion on insomnia heterogeneity and the need for possible phenotyping, we do not intend to provide a complete list of phenotypes or possible clusters. The study picked up the approach of subtyping insomnia by collecting a short questionnaire during anamnesis on possible related symptoms, onset and course of insomnia. We described phenotypical traits of insomniacs with a cohort of sleep disturbed patients from a specialized outpatient clinic for sleep disorders.

Participants and Recruitment

Since 2018, a specialized 14-item insomnia questionnaire has formed part of the clinical routine at the outpatient clinic of the Interdisciplinary Center of Sleep Medicine, Charité—Universitätsmedizin Berlin ( Figure 1 ). The questionnaire is the result of literature research, clinical experience, and consensus of psychologists, neurologist, psychiatrists, and sleep physicians within the sleep center. Patients who visited the outpatient clinic between 01/2019 and 02/2020 and indicated self-reported symptoms presenting a suspicion of insomnia (e.g., difficulties initiating sleep, maintaining sleep, or early morning awakening) according to ICSD-3 criteria were recruited and completed the questionnaire. In total, 486 patients were examined by a physician specializing in sleep disorders and insomnia who confirmed an insomnia diagnosis. The questionnaire did not contain any identifying information. As the questionnaire is part of the clinical routine and the de-identified data has been analyzed retrospectively, ethical review and approval was not required in accordance with the local legislation and institutional requirements. As part of the clinical routine, patients signed informed consent forms allowing de-identified data of their patient file, including the insomnia questionnaire, to be used for research purposes.

Figure 1 . The English translation of the 14-item Insomnia Questionnaire with page 1 and page 2.

Questionnaire

The insomnia questionnaire consisted of 14 items ( Figure 1 presents an English translation of the questionnaire). These included questions related to (1) type of insomnia (SOI—sleep onset insomnia, SMI—sleep maintenance insomnia, EMA—early awakening insomnia, multiple answers possible) at three points in time (start of disorder, progression, current state), (2) progression of insomnia, (3) sleep history of being a light or good sleeper, (4) relatives with sleep disorder, (5) triggers, (6) daytime sleep, (7) sleeping in different environments, (8) sleeping arrangement with partner, (9) alcohol as a sleep aid, (10) referral/ recommendation of general practitioner (multiple answer options), (11) alternative sleep treatments, and (12–14) sleep medication.

Procedure of the examination was standardized and performed by the same physician: On arrival, patients received several sleep questionnaires including the 14-item insomnia questionnaire. They were asked to complete these questionnaires before seeing the physician. During the following in-person consultation, the physician completed a full anamnesis (a patient-reported medical history) and confirmed a diagnosis of a primary insomnia according to ICSD-3 criteria. Next, the questions of the insomnia questionnaire were evaluated. Certain questions were clarified, and missing information added. For example, for question 3, light sleeper was defined. Light sleeper includes patients with a regular bedtime but whose sleep is sensitive to light, temperature, and noise. They need a specific degree of sleep comfort and sleep worse in an unfamiliar environment. These patients can nap during the day and sleep better during vacation and time off (e.g., weekends). They perceive their sleep as non-restorative. They also do not meet the diagnostic criteria of insomnia. The question refers to the time before the insomnia started, mostly referring to childhood / adolescence. For question 6, it was clarified that daytime napping included a daytime situation that explicitly allows for napping. For question 7, it was explained that “weekend” also included the days off work.

Sample size was calculated based on prevalence data and the estimated number of insomnia patients: ca. 30–50% of 328.2 million people (US population estimate 2019) result in about 98.5–164.1 million patients ( 13 ). With an accepted error rate of maximum 5% and a confidence interval of 95%, the sample size was set to at least 400 questionnaires in order to detect sufficiently powerful effects. Statistical analysis was performed using SPSS (IBM SPSS Statistics, Version 20). The patient cohort was described using a descriptive analysis with numbers and percentages ( Table 1 ). In order to investigate possible insomnia subgroups based on phenotypes/characteristics, we compared items with dichotomous answers. Item 7 (sleeping in different environments), item 9 (alcohol as a sleep aid), and item 11 (alternative sleep treatments) each had several subcategories which were consolidated into one overall category. For the text answer of item 5 (trigger) we performed a qualitative data analysis by subjectively grouping the text data and visually presenting the categories. A t-test was used for group comparisons of continuous variables (e.g., age), the chi-square test for dichotomous variables. Significance level was set at 0.05.

Table 1 . Sample description ( n = 456 patients).

Patient Description

Due to missing information that could also not be completed during the in-person consultation with the physician, 30 questionnaires were removed from analysis. The remaining 456 questionnaires were de-identified and analyzed. The patient cohort ( Table 1 ) reported having sleep problems for an average of 11.6 ± 10.9 years (range: 0–82 years, where 0 means the symptoms just started within the past month). The cohort consisted of slightly more female insomniacs (56%) and had an average age of 52.0 ± 15.9 years (range: 18–86 years). More than half of the patients reported having a partner and not living alone (63%), and of those 37% slept in a separate room due to the sleep disorder. If the patient went to a general physician first, 50% were referred to a sleep specialist and 26% to another specialist (neurologist, psychiatrist etc.). In 35% of those cases, the general physician initiated a therapy with sleep medication. In general, 69% of the patients reported having used sleep medication, 23% indicated that they had not. Only 9% mentioned that it was difficult to get sleep medication. While 26% stated they had to pay for sleep medication, 37% said they did not. In Germany, sleep medication for primary insomnia covered by insurance only includes melatonin (only for patients over 55 years) and z-drugs (only for the acute therapy of 4 weeks).

Sleep Characteristics

About 43% of the patients indicated that they had a history of being good sleepers before the insomnia onset, while 48% mentioned that they have always been light sleepers. Forty-three percent reported having a family member with sleep problems. Despite insomnia symptoms, 20% of patients indicated that they were able to fall asleep during the day and 44% sometimes. While 43% of patients reported a trigger for the sleep problems, 42% reported no trigger ( Table 1 ). Figure 2 presents a categorization of the reported triggers. The most frequent triggers were of psychological nature (22%) including depression, anxiety, post-traumatic stress disorder, death of a family member, trauma, rape, psychotherapy etc. Stress was listed as a separate category but is to be considered as a subcategory of psychological triggers (additional 11%). Work related triggers including change or loss of job, freelance work, work problems, shift work, long work hours, workload, mobbing/ bulling etc. accounted for 15%.

Figure 2 . Insomnia triggers organized by categories. Psychological triggers include depression, fear, trauma, etc. Stress may be considered a subgroup of psychological triggers. Family triggers include birth, children, marriage, divorce, etc. Medical triggers include sickness, operations, etc. Work triggers include mobbing, loss of job, change of job, workload, etc. Environment triggers include noise, lighting, neighborhood, etc. Other triggers include smoking, attitude, etc. n/a, not available.

The question about sleep in a different environment (item 7 of the questionnaire) included three subcategories: sleep during vacation, sleep at weekends, and sleep in unfamiliar surroundings. Sleep during vacation was perceived as better by 21% ( n = 84), sometimes better by 30% ( n = 121), and not at all better by 49% ( n = 198). Sleep at the weekend was perceived as better by 18% ( n = 70), sometimes better by 26% ( n = 103), and not at all better by 56% ( n = 224). Sleep in unfamiliar surroundings was perceived as better by 5% ( n = 19), sometimes better by 17% ( n = 68), and not at all better by 78% ( n = 304). We consolidated the subcategories in one general environment variable. First, sleep in a different environment (in general) was considered better if a patient answered “yes (sleep better)” to at least one of the subgroups. The remaining patients were categorized into the sometimes group if they answered “sometimes” to at least one of the subcategories. Then, the remaining patients were categorized into the “no (do not sleep better)” or “no answer” category. In general, 26% indicated that they sleep better in different environments, 28% sometimes, and 37% not at all ( Table 1 ).

The question for alternative non-medical treatments (item 11) also included three subcategories: sport, sleep hygiene, and relaxation techniques. Sport only helped in 7% ( n = 26), helped sometimes in 32% ( n = 130), and did not help in 46% ( n = 185). Sleep hygiene helped in 5% ( n = 18), helped sometimes in 29% ( n = 103), and did not help in 43% ( n = 154). Relaxation techniques helped in 5% ( n = 19), helped sometimes in 32% ( n = 117), and did not help in 38% ( n = 142). We combined the subcategories into one overall variable of non-medical treatment in the same way as for item 7. In general, 9% of the patients indicated that an alternative treatment helps, 42% mentioned it helped sometimes, and 33% reported it did not help at all ( Table 1 ).

Alcohol as a sleep aid (item 9) included two subcategories: alcohol as a sleep aid for sleep onset and alcohol as a sleep aid for sleep maintenance. While 40% ( n = 112) indicated alcohol helps with SOI symptoms, it did not change sleep onset in 41% ( n = 116) and symptoms got worse in 19% ( n = 54). Alcohol helped with SMI symptoms in 11% ( n = 31), did nothing in 46% ( n = 123), and got worse in 43% ( n = 116). We also consolidated this variable. Alcohol as a sleep aid in general helped, if a patient answered “sleep got better” to at least one of the two subcategories (without a “sleep got worse” for the other category). Alcohol worsened sleep if a patient answered at least once “got worse” (without a “got better” for the other category). We added the answer option “alcohol helps sometimes” for patients that answered “got better” to one of the categories and “got worse” to the other. The remaining patients were categorized as “no change” or “no answer.” In general, alcohol helped in 16%, helped sometimes in 11%, and did not help (or even got worse) in 37% ( Table 1 ).

Table 2 presents a further description of insomnia subtypes based on these sleep characteristics. We dichotomized the answers into yes/no in order to create a more equal group distribution for comparison. Patients with a sleep history of being light sleepers even before insomnia onset, had significantly longer insomnia symptoms than patients with a sleep history of being good sleepers ( p < 0.05). Patients with a family history of sleep problems were significantly more frequently female ( p < 0.05), had suffered from insomnia symptoms significantly longer ( p < 0.01), and presented significantly more EMA symptoms ( p < 0.05) than patients without a family history of sleep problems. Patients who were able to sleep during the day were significantly more frequently male ( p = 0.001) and displayed fewer SOI ( p < 0.001) and fewer EMA symptoms ( p < 0.01) than patients who could not sleep during the day. Patients with no trigger displayed a tendency to having a longer insomnia duration than patients with a trigger ( p = 0.05). Patients who were able to sleep better in different environments were significantly younger ( p < 0.001) and showed a tendency to shorter insomnia duration ( p = 0.05) than patients who did not sleep better in another environment. Patients for whom alcohol helped as a sleep aid were significantly younger ( p < 0.001) and presented significantly more SOI symptoms ( p < 0.001).

Table 2 . Description of possible insomnia phenotype subgroups based on sleep characteristics.

Insomnia Symptom Subtypes and Progression

At time of visit, 54% of patients presented SOI symptoms, 66% SMI symptoms, and 45% EMA symptoms ( Table 3 ). In 57% of the patients, there was a combination of those symptoms. Patients with SOI symptoms reported on average that they needed 85.6 ± 55.0 min to fall asleep. Patients with SMI symptoms reported waking up for about 79.0 ± 58.2 min after sleep onset. And patients with EMA symptoms reported that they woke up on average 79.0 ± 56.5 min too early in the morning. Patients with EMA symptoms (not exclusively, combination of symptoms possible) had the shortest history of sleep problems (10.2 ± 9.1 years, range: 0–44 years) compared to patients with SOI symptoms (12.0 ± 9.8 years, range: 0–82 years) and patients with SMI symptoms (11.5 ± 10.6 years, range: 0–82 years). Differences were not significant.

Table 3 . Patient description by insomnia subgroups based on symptoms over time.

Table 3 presents the possible change of sleep symptoms over time by type of sleep symptoms. There was no significant change in SOI or SMI symptoms. Only EMA symptoms significantly increased over time ( p = 0.016). Figure 3 presents the progression in severity of the sleep disorder. Fewer than 10% reported an improvement of symptoms, while in 41% the sleep disorder got worse. In 20% the symptoms showed a periodic pattern. The progression was independent of current symptoms.

Figure 3 . Progression of symptoms by insomnia subgroups. Patients were divided into subgroups of current insomnia symptom. Symptoms are not exclusive, they can occur either as single symptom or in occurrence with other symptoms. SOI, Sleep onset insomnia; SMI, sleep maintenance insomnia; EMA, early morning awakenings insomnia. A patient with a periodic pattern of insomnia experiences weeks or months long periods with insomnia symptoms alternating with symptom free periods. For comparisons between symptom groups, p was calculated with chi-square tests. Results were not significant at a 0.05 level. The sum of the subcategories does not add up to 100% as we refrained from displaying the category “missing data and multiple answers” (7% All patients, 7% SOI, 6% SMI, and 7% EMA).

A distinct cohort of insomnia patients that reported to a special outpatient clinic for sleep disorders revealed that about 40–50% of the patients mentioned a trigger for the sleep problems, were not good sleepers to begin with (light sleepers), had a family history of sleep problems, and had a progressive course of insomnia. Over one third were not able to fall asleep during the day. Insomnia with SMI symptoms was most frequent, as well as a psychological trigger. Over time, EMA symptoms increased. Alternative non-medical treatments were only lastingly effective in fewer than 10%. Over two thirds of the patients (69%) had tried sleep medication. One of the unique traits of our cohort is the duration of the sleep problem before the visit to a specialist (over 11 years). For most, the sleep specialist/clinic is not the first point of contact. Thus, our patient cohort is not comparable to one from a general physician or population-based cohort.

Our results emphasize the insomnia heterogeneity and the need for phenotyping. Following, we will first discuss the characteristics assessed with our questionnaire starting with some new aspects that are currently not commonly asked (history of being a light sleeper, daytime sleep, effects of alternative treatments, alcohol, temporal stability/change of insomnia symptoms). Then, we will review the current literature for further possible phenotypes. Table 4 presents an overview.

Table 4 . Overview of discussed phenotypes.

Phenotypes—Based on Our Cohort

Sleep history.

Almost half of our cohort (48%) presented a bad sleep history, indicative of an idiopathic insomnia.

There are no clear biomarkers or diagnostic criteria to distinguish between psychophysiological and idiopathic (chronic) insomnia ( 14 ). In order to identify idiopathic insomnia, we ask the patient for their sleep history, specifically before insomnia onset. Did the patient always experience poor (light) sleep, or were they a fairly good sleeper? We assume that light sleep is the pre-stage of insomnia, but not every light sleeper needs to develop insomnia, indicating that these variables are not predictors for differentiating between psychophysiological and idiopathic insomnia. Whether this distinction of good and bad sleep before developing insomnia influences therapy will need to be further investigated. Also, the term “light (bad)” sleep needs to be clearly defined and standardized.

Daytime Sleep

Using our questionnaire, we found in our cohort that 34% of patients reported not being able to take a nap during the daytime despite being tired and despite having the explicit opportunity of taking a nap. Those patients were predominantly women with more SOI and more EMA symptoms compared to patients who were able to fall asleep during the day. They did not differ regarding the duration of their insomnia symptoms.

Currently, it is not common during insomnia diagnosis to ask whether a patient is able to fall asleep during the day or to conduct a Multiple Sleep Latency Test (MSLT) for objective assessment. Our own experience with insomnia patients, however, showed how important this question is. We experienced that patients who sleep poorly at night and are tired during the day, but cannot sleep in the day either, usually have a higher degree of insomnia. They tend to suffer for more nights a week and are more resistant to therapy. In contrast, the possibility of falling asleep during the day, in front of the television, in the car, on public transport, in a meeting, or in other quiet surroundings, seems to be a sign of a lower degree of insomnia.

The ability to nap during the day has also been a criterion for other indications in the literature. The Hyperarousal Scale by Regestein et al. ( 37 ) provides indirectly a reference to the degree of alertness during the day and thus to the inability to fall asleep. Khassawneh et al. ( 38 ) used the scale together with the patient's subjective statement that they cannot nap during the day and found that patients with hyperarousal and short sleep duration have more cognitive deficits in memory tests. Li et al. ( 39 ) used the MSLT with a threshold value of 14 min to define hyperarousal. Drake et al. ( 40 ) also used the MSLT and investigated sleep disturbances due to commonly experienced stressful situations to identify factors representing the construct of “stress-related” vulnerability to sleep disturbance. Subjects with a high Ford Insomnia Response to Stress Test (FIRST) score had poorer sleep quality at night and higher latencies of sleep in the MSLT. Roehrs et al. ( 15 ) performed the MSLT in 95 patients with primary insomnia (32–64 years) and in 55 healthy sleepers and found a higher sleep latency in insomniacs (13.2 ± 4.65 min vs. 11.0 ± 4.93 min). However, the difference is small and the variability among insomniacs is high (between 2 and 20 min). The MSLT is still a questionable method for diagnosing insomnia, but it may be a possible tool for subtyping insomnia with regard to the ability to fall asleep during daytime. Espie et al. ( 41 ) examined daytime symptoms of 11,129 participants with ( n = 5,083) and without insomnia, coming from different backgrounds. Of the analyzed items (energy, concentration, relationships, ability to stay awake, mood, and ability to get through work), the items “energy” and “mood” turned out to be the two most important parameters for insomniacs, but not the item “ability to stay awake.” The importance of the criterion daytime sleepiness and/or ability to stay awake seems therefore recognized, but not yet uniformly defined and requires further research.

Alternative Treatment (Behavioral Therapy)

In our cohort, about 83% of the patients have tried at least one of these alternative non-medical behavioral treatments: sport, sleep hygiene, and/or relaxation techniques. In one third of the patients (33%) these techniques did not help. There were no significant age, gender, or symptom differences between patients with effective alternative treatments and patients where it was not effective. However, we did not investigate the severity of insomnia and it may be possible that patients where the alternative treatments did not show a positive effect may be patients with more severe insomnia.

Therapy recommendations for insomnia include a multi-modal behavioral therapy including psychological elements (e.g., CBT) as the first therapeutic step which many patients do complete, most commonly even before they arrange a visit to a specialist ( 42 ). This is also what we found in our cohort. Most of our patients have tried to educate themselves on their sleep problems, have tried to improve their sleep hygiene, have tried alternative non-medical treatments (e.g., sport, relaxation, etc.), and already went to either a natural health practitioner, homeopath, psychologist or psychotherapist. Currently, CBT is not yet good enough established in Germany as a definite treatment for insomnia. Studies have shown that CBT had less of an effect on insomniacs with short sleep duration ( 9 ). We assume that this also applies to patients with a more severe insomnia. However, severity has yet to been clearly defined. Patients will most likely show a similar reaction to phytopharmacology or alternative “smart” therapy (e.g., acoustic or electrical stimulation). A future quality check and standardization of CBT methods may be helpful in order to use the success of alternative treatment/behavioral therapy as a phenotypical criterion. We hypothesize that successful CBT is mainly linked to mild insomnia. For moderate to severe insomnia, CBT should be a necessary concomitant therapy.

In our cohort, only about 26% mentioned that alcohol helps with sleep problems in general. Patients for whom alcohol helped were significantly younger and presented more SOI symptoms. A more detailed analysis showed that alcohol helped especially with sleep onset (40%), less with sleep maintenance (only 11%). In 43% of our patients, alcohol even worsened sleep maintenance, which other studies confirmed ( 16 ). However, in almost half of our patients, alcohol showed no change.

Alcohol is a widely used sleep aid. Asking for the soporific effect of alcohol should become standard during insomnia anamnesis, as well as asking for the soporific effect of drugs (CBD, cannabis, etc.) which have become more and more a topic of sleep research ( 43 ). It is surprising that in our cohort many patients reported a lack of positive effect of alcohol as a sleep aid. It may be that the alcohol amount consumed was not high enough, as we did not ask for specifics.

Symptoms at Time of Insomnia Onset

In our cohort, 57% had SOI symptoms when the insomnia started (in 74% as a combination with other symptoms), 66% had SMI symptoms at the beginning (in 79% as a combination of symptoms), and 40% started with EMA symptoms (in 96% with other symptoms). The majority had a combination of several symptoms. Hence, in most cases of insomnia the sleep disorder started with SMI symptoms (either as single symptom or in combination). We found that patients with single SOI or single EMA were significantly younger than patients with a SOI combination (single: age 47 ± 17 years, combination: age 52 ± 16 years; p < 0.01) or EMA combination (single: age 39 ± 13 years, combination: age 51 ± 15 years; p < 0.01), respectively.

Bjorøy et al. ( 16 ) also investigated subtypes of insomnia in an extensive web-based survey with 64,503 patients who had displayed insomnia for >6 months. Here, 60% of the younger insomniacs (on average 37 years) showed SOI symptoms, either as a combination with SMI and/or EMA symptoms or as a single symptom. Confirming our own results, Bjorøy et al. ( 44 ) also found that SOI as a single symptom was more frequent in younger insomniacs, a SOI symptom combination more frequent in older insomniacs. They revealed further predictors for a symptom combination including female gender, evening chronotype, less education, and being single. While we do not assess aspects such as chronotype, they are important. Literature has shown that there is a higher insomnia prevalence in general in people with an evening chronotype. Insomniacs with a symptom combination also showed a higher comorbidity with depression, anxiety, and a higher use of alcohol and sleeping pills ( 16 ).

Symptom Stability Over Time

Not just the severity, but also the symptoms can change over time. In our cohort, prevalence of SOI and SMI symptoms did not change; EMA symptoms, however, significantly increased from 40 to 45% from first noticing those symptoms to the present (visit to a sleep specialist). Patients with SOI symptoms showed a tendency of an increase of SOI in symptom combination instead of as a single symptom (from 74 to 81%).

An early study of Hohagen et al. ( 17 ) also investigated the progression of insomnia symptoms and possible temporal stability of different patterns in 328 patients (18–65 years). In only 4 months, they discovered a >50% change in SOI, SMI, and EMA symptoms. Only in rare cases did a specific and single symptom insomnia (either SOI, SMI, or EMA) change from one to another single symptom. However, in many single symptom insomnia cases another symptom occurred over time while the first symptom stayed dominant. This tendency was also seen in our cohort regarding the SOI symptoms.

Family History

Almost half of our patient cohort (43%) reported a family history of disturbed sleep/insomnia. These patients were foremost female and presented more EMA symptoms than patients without a family history present.

A specific gene for insomnia is not known but a genetic predisposition cannot be completely ruled out ( 18 , 19 ). A twin study of children revealed a moderate inheritability of insomnia, and another study reported 35% inheritability ( 20 , 21 ).

In our cohort, almost every second patient (43%) reported a trigger. Patients with or without a trigger in our cohort did not differ regarding age, gender, and insomnia symptoms. However, those patients with no triggers showed a tendency to longer insomnia duration then the ones with a trigger. Here, it may be possible that the start of the trigger (whether sudden or slowly, unconsciously developing) may have an impact on the perception of insomnia as a chronic condition. Within our cohort, most frequently named were psychological triggers (e.g., depression, anxiety, trauma, burnout), family triggers (e.g., birth, divorce, custody battles), and medical/biological triggers including surgery and other illnesses. Work triggers (e.g., mobbing/ bulling, job loss) and stress as a separate psychological trigger came next.

Triggers are part of Spielman's theoretical model (1987) of factors causing chronic insomnia. The 3Ps consist of predisposing factors, precipitating factors which trigger acute insomnia, and perpetuating factors ( 22 , 23 ). Triggers would belong to the precipitating factors and may lead to a chronic insomnia. For a working patient, work related stress and job strain may play a bigger role as a trigger and moderator of the insomnia than for those patients that are not working ( 24 ). However, whether the existence of a trigger influences the progression or therapy of insomnia still needs to be further investigated.

Progression of Insomnia

Our patients reported most frequently a negative progression of insomnia (41%); in 26% there were no changes, and only in 7% was there an improvement. On average, the patients suffered from insomnia symptoms for about 11.6 years (range 0–82 years) before seeing a sleep specialist. Patients with predominantly EMA symptoms showed the shortest sleep problem history with 10.2 years (range 0–44 years) compared to patients with SOI or SMI symptoms. About 20% of our patients reported a periodic pattern of symptom severity.

The periodic pattern may be indicative of a non-24 h disorder ( 25 ). A patient with a periodic pattern of insomnia experiences weeks or months long periods with insomnia symptoms alternating with symptom free periods. Green et al. ( 26 ) also investigated the progression of insomnia for over 20 years in 5-year intervals. Patterns included: healthy pattern, episodic pattern, chronic pattern, and a pattern with the development of symptoms in the follow-up period. Chronic insomnia was linked to older women and the working class. It showed that social factors do affect the progression of a sleep disorder, a fact also indicated by Patel et al. ( 27 ) and Arber et al. ( 28 ). There is another distinction of insomnia subtypes by progression introduced by Wu et al. ( 29 ): persistent insomnia, remission, or relapse.

Sleep in Different Environments

Over half of our patients (54%) reported sleeping better in a different environment, including weekends/days with time off from work (51%), vacation (44%), and unfamiliar surroundings in general (22%). The category “unfamiliar surroundings” received the lowest number. Patients may have included job related hotel stays and therefore increased stress level, which may account for the lower number. Patients stating they slept better in a different environment were predominantly younger members of our cohort.

If patients reported sleeping better at weekends or on vacation, this may be an indication that the sleep disorder was caused by work stress or daily routine. In the literature, this is called behavioral induced insufficient sleep ( 30 , 31 ). As only few insomniacs are able to quit their job or family, this category may represent a specific insomnia phenotype. For those, specific interventions are possible including the end of shift work, change to home office work, change from full-time to part-time work, etc.

Further Discussion of Phenotypes

Studies suggest that insomnia is a heterogenic disorder and the identification of different phenotypes or comorbidities is important for personalized treatments ( 45 ). In our study, we presented some new aspects on what insomniacs should be asked during anamnesis and what should be considered during phenotyping. Benjamin et al. ( 32 ) already proposed the following characteristics: (1) life history including demographics, mental and physical health, trauma and life events. This study showed that more women than men and more older people than younger people suffer from insomnia and life events are usually triggers. Such triggers are mostly to be found at home, in health or at work/school, as could also be confirmed with our patients. But who reacts to such a negative trigger with insomnia and why, when, at what age, is not yet known and may possibly have a genetic reason. Further characteristics included (2) subjective sleep quality, (3) fatigue, sleepiness, hyperarousal in the daytime, (4) other sleep disorders, (5) lifetime sleep history, (6) chronotype, (7) depression, anxiety, mood, (8) quality of life, (9) personality, (10) worry, rumination, self-consciousness, sensitivity, (11) dysfunctional beliefs, (12) self-conscious emotion regulation and coping, (13) nocturnal mentation, (14) wake resting state mentation, (15) lifestyle including physical activity and food intake, (16) body temperature, and (17) hedonic evaluation. Other possible non-sleep phenotypes included: MRI, cognition, mood, traits, history of life events, family history, PSG, sleep microstructure, genetics. Blanken et al. ( 11 ) distinguished insomnia subtypes according to the so-called non-sleep categories of life history, mood perception, and personality. Miller et al. ( 33 ) presented an insomnia cluster analysis based on neurocognitive performance, sleep-onset measures of qualitative EEG, and heart rate variability (HRV). They identified two main clusters, depending on duration of sleep (<6 h vs. >6 h). The HRV changes during falling asleep may also play a role, as may the spectral power of the sleep EEG, and parameters from the sleep hypnogram such as sleep onset latency and wake after sleep onset. In one of our own studies, we were able to demonstrate that the increased nocturnal pulse rate and vascular stiffness in insomniacs with low sleep efficiency (<80%) represented an early sign of elevated cardiovascular risk, and thus presented a useful tool for phenotyping insomnia ( 34 ). In the future, other objective characteristics may include biomarkers or radiological features ( 46 , 47 ).

Further characteristics that may play a role but have not yet been mentioned or investigated are the age of the patient during insomnia onset, frequent nocturnal awakenings, the time it takes to see a specialist, and the kind of insomnia onset, slowly progressing or suddenly unexpected. There is no defined age at which the likelihood of insomnia increases, but we know that menopause is a major trigger for women. Grandner et al. ( 35 ) were able to show that getting older alone is not a predictor of insomnia, it rather includes multifactorial events. The question of how long it takes to see a specialist is also part of the Sleep Condition Indicator (SCI) by Espie et al. ( 36 ). They asked whether the insomnia had lasted longer than a year, 1–2, 3–6, or 7–12 months. We can easily agree with such a classification in terms of content. Many patients who wake up frequently at night consider this an insomnia with SMI symptoms. Frequent nocturnal awakenings, but with the ability to fall asleep again straight away, are according to the definition not considered a SMI insomnia. We did not address this in the present study, which presents a limitation. While it is mentioned in the DSM-5 as an independent sign of insomnia, patients affected by frequent nocturnal but subjectively normal sleep lengths and still restful sleep do not (yet) have insomnia. Whether it is an independent phenotype or a preliminary stage of a SMI insomnia should be further examined and defined. It also needs to be clarified whether devices for sleep registration help us with phenotyping. Polysomnography is certainly a very strong phenotypic feature when sleep time is very short, wake times after sleep onset is high and deep and/or dream sleep and sleep efficiency are not optimal. However, the current status is such that it is not suitable for diagnosis ( 48 ). In the near future, technical advances will help to provide objective, long-term sleep data, which are important for diagnosis, subtyping, and therapy for different types of insomnia.

Currently, questionnaires have been used to assess insomnia. The most known questionnaires include the ISI and the Pittsburgh Sleep Quality Index (PSQI). These are valid instruments ( 6 , 49 ). However, there are a number of other questionnaires used for insomnia such as the Amsterdam Resting-State Questionnaire (ARSQ), Dysfunctional Beliefs and Attitudes About Sleep Scale (DBAS), Sleep-Related Behaviors Questionnaire (SRBQ), Sleep Functional Impact Scale (SFIS), Leeds Sleep Evaluation Questionnaire (LSEQ), Glasgow Sleep Effort Scale (GSES) ( 50 – 55 ). In 2014, Espie et al. ( 36 ) introduced the SCI which presented a good instrument for identifying the presence of insomnia and also allowed for time differentiation. Also, the short version with only 2 questions seems valid, where questions are asked about the number of nights in the past month with poor sleep and about the trouble in general caused by sleep ( 56 ). Kalmbach et al. ( 57 ) presented a differentiation between good and bad sleepers based on the Presleep Arousal Scale—Cognitive (PSAS-C) and—Somatic (PSAS-S). People with a high PSAS-C have higher sleep latency and wake times after sleep onset, as well as higher MSLT latency and lower sleep efficiency and total sleep time. The PSAS-C in particular seems to be a good measure of the hyperarousal state. Research and official expert recommendations will show which questionnaires should be favored in clinical practice.

Limitations

Our study intended to encourage and further the discussion on insomnia heterogeneity and the need for possible phenotyping. While we introduced some new aspects of phenotyping, we neither provided a complete list of possible phenotypes nor defined specific clusters. Limitations of our study include the fact that further important aspects (e.g., comorbidity, employment, having children, chronotype, employment etc.) may need consideration. Also, some aspects of the questionnaire will need a more precise definition (e.g., light sleeper, daytime napping, weekend/vacation, alternative treatment, alcohol use), patients were not differentiated regarding sleep duration (<6 h vs. >6 h), and the progression of insomnia was observed retrospectively and not investigated prospectively. While our study was performed with patients of a sleep center, there is also need for phenotyping and thorough assessment of those phenotype characteristics in patients of a primary care setting.

As part of a specific Research Topic introduced by Frontiers on the heterogeneity of insomnia, our study provides further ideas on the already existing approaches to phenotyping insomnia patients. The aim of our study was not to examine all conceivable phenotypic features of insomnia, but to help document specific characteristics with simple questions about the onset and course of insomnia during anamnesis. While the clinical relevance of some of those possible phenotypes is not yet clear (e.g., sleep history, trigger, daytime sleep, sleep in a different environment, alternative treatment, insomnia progression/symptom stability etc.), they should play a role in future research and medical care of insomnia patients. We would like to give an impulse for further research in this area, in order to better differentiate insomnia, thus leading to more effective individualized therapy.

Data Availability Statement

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

Ethics Statement

Ethical review and approval was not required for the study on human participants in accordance with the local legislation and institutional requirements. The patients/participants provided their written informed consent to participate in this study.

Author Contributions

IF, TP, and VK had the role of supervision and conceptualized the study. IF was responsible for data collection. NL performed data analysis. All authors were involved in visualization and writing including data interpretation, result discussion, and drafting and reviewing the manuscript.

This was not an industry supported study. The study was initiated and funded by the Charité—Universitätsmedizin Berlin owned funding.

Conflict of Interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Acknowledgments

We would like to thank all the patients that participated, and Hendrik Straße and Sandra Zimmermann involved in data entry and processing.

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Keywords: insomnia, phenotypes, subtypes, heterogeneity, symptom, progression, questionnaire, screening

Citation: Fietze I, Laharnar N, Koellner V and Penzel T (2021) The Different Faces of Insomnia. Front. Psychiatry 12:683943. doi: 10.3389/fpsyt.2021.683943

Received: 22 March 2021; Accepted: 24 May 2021; Published: 29 June 2021.

Reviewed by:

Copyright © 2021 Fietze, Laharnar, Koellner and Penzel. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Naima Laharnar, naima.laharnar@charite.de

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

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Trends in insomnia research for the next decade: a narrative review

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• Volume 18 , pages 199–207, ( 2020 )

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• Daniel Ruivo Marques 1 , 2 ,
• Ana Allen Gomes 2 , 3 ,
• Vanda Clemente 2 , 4 ,
• José Moutinho dos Santos 4 ,
• Joana Serra 4 &
• Maria Helena Pinto de Azevedo 5  

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Insomnia disorder has known striking developments over the last few years. Partly due to advances in neuroimaging techniques and brain sciences, our understanding of insomnia disorder has become more fine-tuned. Besides, developments within psychological and psychiatric fields have contributed to improve conceptualization, assessment, and treatment of insomnia. In this paper, we present a list of promising 10 key “hot-topics” that we think in the next 10 years will continue to stimulate researchers in insomnia’s domain: increasing of systematic reviews and meta-analyses; improvement of existing self-report measures; increasing of genetic and epigenetic investigation; research on new pharmacological agents; advances in neuroimaging studies and methods; new psychological clinical approaches; effectiveness studies of e-treatments and greater dissemination of evidence-based therapies for insomnia; call for integrative models; network approach using in insomnia; and assessment of insomnia phenotypes. The breadth of all these topics demands the collaboration of researchers from different scientific fields within sleep medicine. In summarizing, in the next decade, it is predictable that insomnia’s research still benefit from different scientific disciplines.

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Marques, D.R., Gomes, A.A., Clemente, V. et al. Trends in insomnia research for the next decade: a narrative review. Sleep Biol. Rhythms 18 , 199–207 (2020). https://doi.org/10.1007/s41105-020-00269-7

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Insomnia: The Latest Research

If you have trouble falling asleep or staying asleep, you may have insomnia , the most common sleep disorder . Between 10% and 30% of adults have chronic insomnia, and many more deal with it from time to time. Here’s a look at some of the latest research on this condition, its causes, and treatments that may help.

Insomnia Medications

A new type of drug is giving doctors another option when it comes to prescription medication to treat insomnia .

Orexin receptor antagonists. Some of the latest sleep medications are known as orexin inhibitors. They block the action of a brain chemical that keeps you alert, called orexin. Two of these drugs include:

• Daridorexant ( Quviviq )
• Lemborexant ( Dayvigo )
• Suvorexant ( Belsomra )

Scientists are studying two other similar drugs in clinical trials .

All sleeping pills come with risks and side effects. With some, you can develop a tolerance, which means it stops working effectively at the recommended dosage, or even feels like you can’t fall asleep without them. Some can cause you to walk, eat, or even drive in your sleep. Most can leave you feeling groggy the next day. Doctors usually only prescribe them for the short term, and you have to stop using them gradually.

Melatonin. Your body makes this hormone as the sun goes down, telling you it’s time to get sleepy. A prescription form of melatonin helps you fall asleep by acting like melatonin in your brain.

Melatonin supplements are often sold as a treatment for insomnia. But both the American Academy of Sleep Medicine (AASM) and the American Academy of Physicians don’t recommend it, saying there isn’t enough evidence it actually works.

It’s also hard to know what you’re getting when you buy supplements . A 2017 analysis of dozens of supplements found that more than 70% of the time, the amount of melatonin in the product didn’t match what was on the label.

Nondrug Insomnia Therapies

Your doctor probably won’t prescribe a sleeping pill until you’ve tried other treatments. Scientists are studying nondrug therapies that can help insomnia, but cognitive behavioral therapy is one option sleep experts often recommend first.

CBT-I. The AASM put out new guidelines in early 2021 strongly recommending cognitive behavioral therapy for insomnia (CBT-I). When you do CBT-I, you meet with a therapist to learn how to change thoughts and behaviors that may be keeping you from getting a good night’s sleep. It involves several techniques that you may try one at a time or in combination.

• Cognitive restructuring. The therapist will help you identify and change unhelpful thoughts and feelings that may be affecting your sleep, like anxiety about insomnia or unrealistic expectations.
• Stimulus control. This means setting up a sleep environment with no distractions, going to bed and getting up at the same time every day, and leaving the bedroom, rather than tossing and turning, when you can’t get to sleep.
• Sleep restriction. You’ll record the amount of time you spend sleeping with a sleep diary, then start staying in bed for only that amount of time plus 30 minutes. You’ll probably get less sleep at first. But the idea is to make yourself tired enough to get solid sleep, then gradually increase your time in bed.
• Relaxation training. Your therapist can teach you relaxation techniques like breathing exercises and meditation that may help calm your mind.
• Sleep hygiene. This includes a range of habits that promote good sleep, like getting exercise , cutting out late-night eating, alcohol and caffeine , and keeping your bedroom cool, dark, and quiet.

Therapists have traditionally provided CBT-I face-to-face. But throughout the COVID-19 pandemic, doctors have been working on alternatives to in-person sessions that appear to get good results.

Two recent studies showed that CBT-I conducted over the phone or through a video link is just as effective as face-to-face therapy. In 2020, the FDA approved an app that delivers CBT-I by prescription. Research into the app and web-based therapy programs has found that so-called digital CBT-I does help relieve insomnia.

Light therapy. Sunlight helps control your body’s sleep/wake cycle by regulating the sleep hormone melatonin. When that cycle is thrown off, artificial light that mimics sunlight can help, a practice called light therapy. You sit in front of a special box that puts out an intense light at the specific time of day and for the length of time your doctor prescribes. Research has found it’s particularly helpful with resetting your body clock if you work odd hours, like a night shift, or have jet lag. But it can also relieve insomnia.

Acupuncture. A large number of studies have looked at whether acupuncture may be an effective treatment for insomnia. Two reviews of the research published in 2021 found that acupuncture does help people sleep longer and wake up less often.

Causes of Insomnia

Other research is examining why people have insomnia and what can make it worse. Among the factors under review:

• Genetics. Scientists are looking at whether the likelihood of having insomnia is something you’re born with. They’ve identified specific areas in our genes that appear to play a role in insomnia symptoms.
• Light pollution. Korean researchers may have found a link between city lights and insomnia. A 2018 study showed that the more artificial outdoor light people were exposed to at night, the more likely they were to use sleeping medication.
• COVID-19 pandemic. An AASM survey from March of 2021 found that more than half of American adults reported sleep problems, including insomnia, since the pandemic began.

And there’s evidence the virus itself can cause you to lose sleep. A 2020 British study found 5% of people treated for COVID-19 had insomnia in the 6 months after their diagnosis.

Insomnia and Dementia

Other recent studies have looked at a possible link between insomnia and thinking and memory problems. Poor sleep could mean cognitive impairment later in life.

One 2021 study looked at people who reported having insomnia when they were younger, and then had issues with cognition years later. The people most likely to end up with thinking and memory problems were those who had sleep-onset insomnia, meaning their main symptom was trouble falling asleep. Other research published in 2020 found that people who have insomnia and sleep less than 6 hours a night had double the risk of cognitive impairment.

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Insomnia: Symptoms, Causes, and Treatments

What it is and how to help you get back your restful nights

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Table of Contents

What Is Insomnia? 

Symptoms of insomnia, what causes insomnia , how is insomnia diagnosed , treatments for insomnia .

• Insomnia is defined as difficulty either falling or staying asleep that is accompanied by daytime impairments.
• Nighttime insomnia symptoms can include trouble sleeping and early waking.
• Daytime insomnia symptoms may include fatigue, impaired memory, and irritability.
• There is no single established cause of insomnia, and insomnia disorders can often occur alongside other health conditions.

Insomnia is one of the most common health concerns among adults. Insomnia causes sleep issues that interfere with daily life and can be debilitating for some people. Many factors may contribute to insomnia, including stress, medications, and an individual’s sleep habits and environment. 

Insomnia is a sleep disorder characterized by difficulty falling asleep, staying asleep, or both, even if you have ample time and a bedroom environment conducive to restful sleep. An insomnia diagnosis requires these sleep troubles to also cause daytime impairments, such as sleepiness or difficulty concentrating.

Up to two-thirds of people occasionally experience insomnia symptoms . These bouts of sleeplessness may or may not meet the criteria for a formal diagnosis of insomnia, depending on how long they last and whether they cause distress or interfere with daily functioning. But it is important for anyone who has concerns about their sleep to discuss them with a health professional for proper diagnosis and treatment.

A doctor can ask questions to better understand your situation and order tests to determine if an insomnia diagnosis is appropriate. Symptoms of insomnia can overlap with symptoms of other sleep disorders, so it is important to work with a professional rather than attempting to self-diagnose.

Insomnia that goes untreated, leading to long-term sleep deprivation, is linked with a number of harmful effects Trusted Source UpToDate More than 2 million healthcare providers around the world choose UpToDate to help make appropriate care decisions and drive better health outcomes. UpToDate delivers evidence-based clinical decision support that is clear, actionable, and rich with real-world insights. View Source , including lower quality of life and increased risk for substance abuse, chronic pain , heart disease , and diabetes .

Types of Insomnia

The two main types of insomnia are acute insomnia and chronic insomnia. Acute insomnia describes sleep difficulties that last for a few days or weeks, but not longer than three months. Short-term insomnia can often be traced to an external cause or life stressor like divorce, the death of a loved one, or a major illness. If acute insomnia persists over multiple months, it becomes classified as chronic insomnia.

Chronic insomnia is when a person experiences sleeping difficulties and related daytime symptoms, like sleepiness and attention issues, at least three days per week for longer than three months. It is estimated that about 10% to 15% of people have chronic insomnia.

People with chronic insomnia commonly feel distressed about their inability to sleep and the daytime symptoms caused by those sleep issues. Symptoms are generally severe enough to affect a person’s work or school performance as well as their social or family life.

The symptoms of insomnia include various sleep-related difficulties and daytime problems. Common sleep issues that can signal the presence of insomnia include:

• Trouble falling asleep
• Trouble staying asleep throughout the night
• Unwanted early morning waking
• Resisting sleeping at bedtime in children and teens
• Difficulty sleeping without a caregiver’s help in children and teens

In addition, insomnia causes daytime symptoms related to sleep loss. Those with insomnia often report feeling fatigued during waking hours, which may lead to impaired attention or memory. Insomnia-related sleepiness can affect work, school or social performance, and increase the risk of accidents. Insomnia has the potential to negatively influence behavioral health and may contribute to instances of irritability, hyperactivity, or aggressiveness, especially in children.

There is no main cause of insomnia . However, research suggests that in many people insomnia likely results from certain types of physiological arousal at unwanted times, disrupting normal patterns of sleep. Examples of such arousal can include a heightened heart rate, a higher body temperature, and increased levels of specific hormones, like cortisol.

A person’s family history , age , and gender may also play a role in their susceptibility to insomnia. Additionally, insomnia disorders often occur alongside mental health disorders , including depression and anxiety . It is believed that the cause of insomnia may be distinct in people who have both insomnia and mental health conditions.

Risk Factors for Insomnia

While there is no single cause of insomnia, studies have identified factors that can put a person at a greater risk for experiencing insomnia Trusted Source American Academy of Sleep Medicine (AASM) AASM sets standards and promotes excellence in sleep medicine health care, education, and research. View Source . These include, but are not limited to:

• Being a woman or assigned female at birth
• Lower socioeconomic status
• Medical conditions like diabetes and chronic pain
• Other sleep disorders such as restless legs syndrome and sleep apnea
• Mood disorders including depression and anxiety Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. View Source  
• Having an immediate family member with insomnia

It is important to note that not everyone who has one or more of these risk factors will have insomnia, and not everyone with insomnia will have one of these risk factors.

Doctors generally diagnose insomnia by evaluating a person’s sleep habits and medical history. 

Typically, a patient’s description of their symptoms informs their insomnia diagnosis. A doctor may instruct patients to keep a sleep diary for a week or more, which can provide insight about a person’s sleep duration, perceived sleep quality, and lifestyle choices that may contribute to sleep problems. Other self-reporting diagnostic tools, including the Pittsburgh Sleep Quality Index, may be used by medical professionals in a clinical setting to determine the severity of insomnia symptoms.  

If a doctor needs to rule out other sleep disorders that could be causing a person’s symptoms, other assessments, such as a sleep study , may be ordered.

Treatment for insomnia depends on how long a person has been experiencing sleep issues and any specific factors that are contributing to their sleep loss. If insomnia is associated with another condition, such as sleep apnea or depression, treatment of the other condition often improves sleep.

It is important to get help with insomnia sooner than later. For people with short-term insomnia, care may be focused on discussing practices to support sleep hygiene . Temporary use of a prescription sleep aid may be an option if the insomnia is causing high levels of concern or distress. 

A few treatment approaches are available for people with insomnia that persists for weeks or months.

Cognitive Behavioral Therapy for Insomnia (CBT-I)

Experts consider cognitive behavioral therapy for insomnia (CBT-I) to be the most effective initial treatment for chronic insomnia. CBT-I helps people manage anxiety they feel about their sleep issues and establish better sleep habits.

Sleep Medications

If a person experiences significant symptoms from insomnia, or in cases where CBT-I does not help, medication may be recommended. Medication can help promote sleep but may also come with side effects , such as daytime drowsiness or confusion.

Homeopathic Treatments 

Some people with insomnia may be interested in exploring other options, such as melatonin or dietary supplements, yoga , hypnosis , or aromatherapy . However, scientific evidence supporting the use of these methods to treat insomnia is lacking at this time Trusted Source National Center for Complementary and Integrative Health (NICCH) NCCIH funds and conducts research to help answer important scientific and public health questions about complementary health approaches. View Source .

Lifestyle Changes

Maintaining healthy sleep habits after insomnia treatment may help keep insomnia from returning Trusted Source Medline Plus MedlinePlus is an online health information resource for patients and their families and friends. View Source . 

• Set a sleep schedule: Maintain the same bedtime and wake time every day, even on weekends.
• Establish a dedicated sleep space: Reserve use of the bed for only sex and sleep.
• Be mindful of substance use: Curb consumption of caffeine , alcohol , or nicotine, especially near bedtime
• Control light exposure: Try to keep the bedroom both dark and quiet, and refrain from watching television or using other electronics that emit blue light before bed. 
• Keep sleep-related anxiety in check: If you are experiencing anxiety about sleep troubles, get out of bed and try a relaxing activity like reading, taking a bath, or meditating. 
• Adjust your eating habits: Avoid eating large meals too close to bedtime.
• When Your Partner Snores, No One Sleeps
• Can the Rise of Chronoworking Help Fix Our Sleep?
• Streamlining Cognitive Behavioral Therapy for Chronic Insomnia
• Blood-based Marker Developed to Identify Sleep Deprivation

About Our Editorial Team

Eric Suni, Staff Writer

Medically Reviewed by

Dr. Anis Rehman, Internal Medicine Physician MD

References 6 sources.

Bonnet, M., & Arand, D. (2022, April 15). Risk factors, comorbidities, and consequences of insomnia in adults. In R. Benca (Ed.). UpToDate., Retrieved June 5, 2023, from

American Academy of Sleep Medicine. (2014). The International Classification of Sleep Disorders – Third Edition (ICSD-3). Darien, IL.

Bjorøy, I., Jørgensen, V. A., Pallesen, S., & Bjorvatn, B. (2020). The prevalence of insomnia subtypes in relation to demographic characteristics, anxiety, depression, alcohol consumption and use of hypnotics. Frontiers in Psychology, 11, 527.

Bonnet, M. H., & Arand, D. L. (2021, June 18). Evaluation and diagnosis of insomnia in adults. In R. Benca (Ed.). UpToDate., Retrieved June 5, 2023, from

National Center for Complementary and Integrative Health. (2015, September). Sleep disorders: In depth., Retrieved June 5, 2023, from

A.D.A.M. Medical Encyclopedia. (2022, May 12). Changing your sleep habits. MedlinePlus., Retrieved June 5, 2023, from

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Insomnia and its impact on physical and mental health

Affiliation.

• 1 Sleep Research and Treatment Center, Department of Psychiatry, Pennsylvania State University College of Medicine, 500 University Drive H073, Hershey, PA, 17033, USA, [email protected].
• PMID: 24189774
• PMCID: PMC3972485
• DOI: 10.1007/s11920-013-0418-8

In contrast to the association of insomnia with mental health, its association with physical health has remained largely unexplored until recently. Based on findings that insomnia with objective short sleep duration is associated with activation of both limbs of the stress system and other indices of physiological hyperarousal, which should adversely affect physical and mental health, we have recently demonstrated that this insomnia phenotype is associated with a significant risk of cardiometabolic and neurocognitive morbidity and mortality. In contrast, insomnia with normal sleep duration is associated with sleep misperception and cognitive-emotional arousal, but not with signs of physiological hyperarousal or cardiometabolic or neurocognitive morbidity. Interestingly, both insomnia phenotypes are associated with mental health, although most likely through different pathophysiological mechanisms. We propose that objective measures of sleep duration may become part of the routine evaluation and diagnosis of insomnia, and that these two insomnia phenotypes may respond differentially to biological versus psychological treatments.

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Figure 1. Heuristic model of the underlying…

Figure 1. Heuristic model of the underlying pathophysiological mechanisms and clinical characteristics of the two…

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• v.5(4); Oct-Dec 2016

Prevalence of chronic insomnia in adult patients and its correlation with medical comorbidities

Swapna bhaskar.

1 Department of Family Medicine, St. Philomena's Hospital, Bengaluru, Karnataka, India

D. Hemavathy

2 Department of Family Medicine, St. Martha's Hospital, Bengaluru, Karnataka, India

Shankar Prasad

3 Department of Medicine, St. Philomena's Hospital, Bengaluru, Karnataka, India

Introduction:

Insomnia is one of the common but neglected conditions seen in family practice with long term and serious effects on health of a patient. Family physicians have the responsibility of diagnosing and adequately treating this. This study was done to find the prevalence of chronic insomnia in adult patients visiting a family medicine outpatient department (OPD) in a hospital and to assess the risk factors and co morbidities associated with it.

Materials and Methods:

A cross-sectional study was done in the family medicine OPD at St. Philomena's Hospital, Bengaluru. All adult patients attending the OPD from September 1 to October 30, 2015 were enrolled in the study after obtaining written consent. Athens Insomnia Scale was used to diagnose insomnia and information regarding medical co morbidities was collected. Data was analyzed for the prevalence of insomnia and its association with co morbidities.

Chronic insomnia was seen in 33% of the adult population sampled. Increasing age and diabetes were significantly associated with insomnia, while other socioeconomic factors and co morbidities were not significantly associated. Twenty-seven percent of patients who had insomnia did not perceive the condition, which was statistically significant.

Conclusion:

Insomnia is a common sleep disorder which is many times missed by a primary care physician until/unless asked for. Since there is a higher incidence with increasing age and co morbidities such as diabetes, all patients, especially middle-aged and diabetics, should be screened for insomnia by the primary care physician with a self assessed questionnaire and counseled.

Introduction

Insomnia is defined as the subjective perception of difficulty with sleep initiation, duration, consolidation, or quality, which occurs despite adequate opportunity for sleep, and results in some form of daytime impairment.[ 1 ] Chronic insomnia is diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition,[ 2 ] and the International Classification of Sleep Disorders,[ 3 ] which have similar criteria for making the diagnosis. These criteria specify that symptoms must cause clinically significant functional distress or impairment, be present for at least 3 nights/week for at least 3 months, and not be linked to other sleep, medical, or mental disorders. Various studies worldwide have shown the prevalence of insomnia in 10%–30% of the population, some even as high as 50%–60%. It is common in older adults, females, and people with medical and mental ill health.[ 4 , 5 , 6 ] The consequences of insomnia are significant, such as depression, impaired work performance, work- related/motor vehicle accidents, and overall poor quality of life. It is an easy-to-diagnose condition with many self-answerable questionnaires for aid, yet goes unrecognized in a significant number of patients coming to the outpatient department with other comorbid conditions. The objective of this study was to determine the prevalence of chronic insomnia, to look for any association with socioeconomic factors and medical comorbidities, and also to assess the patient's perception of having insomnia.

Materials and Methods

This cross-sectional study was conducted in the family medicine outpatient department (OPD) of a 450-bedded general hospital in Bengaluru - St. Philomena's Hospital. All adult patients attending the OPD from September 1 to October 30, 2015, were enrolled in the study after obtaining written consent. Data about age, gender, education, occupation, monthly family income in rupees, and medical comorbidities were collected using a questionnaire. Athens Insomnia Scale was given to the patient to score; illiterate patients were helped by asking the same questions in their local language. The perception of the patient was asked before answering the insomnia scale. A score of 6 or more was taken as positive for insomnia.

Collected data were alphanumerically coded and entered in an Excel sheet. The analysis was done using SPSS 19.0 software (IBM, Bangalore, India), and the Chi-square test was used for analyzing the association of risk factors. P < 0.05 was considered statistically significant for Chi-square test.

Inclusion and exclusion criteria

All adult patients attending family medicine OPD were included in the study. Patients <18 years and >60 years, patients with known psychiatric illnesses, acutely ill patients, and alcoholics were excluded from the study.

Two hundred and seventy-eight patients were enrolled in the study after obtaining consent – 180 were female and 98 were male.

Table 1 shows the prevalence of insomnia with age and gender. Insomnia was found in 92 (33%) patients - 63 (68%) were female and 29 (32%) were male. Twenty-nine (32%) patients below the age of 35 had insomnia, of which 20 (69%) were female and 9 (31%) were male. Sixty-three (68%) patients were of age >35 years - of which 43 (68%) were female and 20 (32%) were male.

Prevalence of insomnia with age and gender

Table 2 shows the association of insomnia with socioeconomic variables. Insomnia was found to be significantly higher in patients >35 years of age ( P = 0.015). The educational background did not significantly affect insomnia - 40% of illiterate or people with basic schooling, 19% of undergraduates, 30% of graduates, and 19% of postgraduate degree holders were found to have insomnia. Employment also had no significant correlation with insomnia - 38% unemployed, 33% unskilled laborers, 45% skilled workers, and 30% professionals were found to have insomnia although statistically insignificant. Family income was another insignificant variable - 29% of patients with monthly income <Rs. 25,000 had insomnia, 37% in the group of income between 26,000 and 50,000, 50% with income between 51,000 and 75,000, and 41% with income >Rs. 75,000 had insomnia.

Association of socioeconomic variables with insomnia

Table 3 shows the association of insomnia with medical comorbidities. Patients with diabetes had statistically significant insomnia compared to those without diabetes ( P = 0.001). Fifty percent of patients with diabetes had insomnia compared to 27% without diabetes. Hypertension (37% vs. 32%), ischemic heart disease (50% vs. 33%), thyroid disorders (42% vs. 31%), respiratory disorders (35% vs. 33%), kidney diseases (67% vs. 33%), liver diseases (51% vs. 32%), and other disorders such as arthralgia/tuberculosis/seizures/gastrointestinal disorders (48% vs. 33%) were found to have statistically insignificant correlation with insomnia.

Association of medical comorbidities with insomnia

Table 4 shows the association of actual insomnia with the patient's perception. Twenty-five patients (27%) did not have the perception of insomnia although they had a score of >6 in Athens scale, which had a significant P value ( P < 0.05).

Association of patient's perception with actual insomnia

Review of literature

The present study was done to determine the prevalence of chronic insomnia in the adult population in a family medicine outpatient clinic. In this study, the prevalence was found to be 33% with statistically significant correlation with increasing age and diabetes. A similar study conducted in South India found a prevalence of 18.6% among healthy adults attending a tertiary hospital[ 7 ] Another Indian study identified 15.4% prevalence of insomnia; Incidence was high in persons with comorbid chronic physical illness (28.1%) compared to persons free from that (10.9%), also higher among people living in joint families than those living in a nuclear family and increasing significantly with increasing age.[ 8 ] A recent study among corporate employees in India showed a prevalence of insomnia in 13.8% of participants, of which undiagnosed population was 96.4%. The common comorbid conditions associated with insomnia were anxiety, hypertension, and depression, and alcohol consumption was observed to be significantly higher in the sufferers of insomnia.[ 9 ] Our study showed a much higher prevalence rate compared to the above three Indian studies.

A multinational study done in Latin American countries using Athens Insomnia Scale and other sleep scales in middle-aged females showed 56.6% of surveyed women suffered from either insomnia, poor sleep quality, or both.[ 10 ] The prevalence of insomnia increased with age and menopausal stage. Increasing age, the presence of chronic disease, troublesome drinking, anxiety, depression, vasomotor symptoms, and drug use (hypnotics and hormone therapy) were significant risk factors related to the presence of sleep disturbances. Higher educational level related to less insomnia and better sleep quality. Many other international studies have also shown insomnia to be more common in women and elders.[ 11 , 12 ]

Dr. Ohayan's landmark review of approximately 50 prevalence studies reported roughly 30-20-10 rule for prevalence – i.e., 30% of adults have symptoms, 15%–20% report symptoms, and <10% are likely to meet the diagnostic and statistical criteria.[ 13 ]

A meta-analysis done in the US showed that of the patients attending primary care clinics, more than 50% complained of insomnia, only if specifically asked about it, 30% visit their general practitioners (GPs) on their own initiative, and only 5% go to consultation with the main objective of receiving treatment to solve their problem.[ 14 ]

Another international survey of sleep disorders in general population found that many individuals with insomnia (47%–67%) did not seek medical attention for their sleep difficulties. Among those who sought medical help, 50%–90% received treatment. Thus, insomnia remains a largely underdiagnosed and undertreated problem.[ 15 ]

A study on Malaysian patients attending primary care clinics showed that 38.9% patients had frequent insomnia symptoms (>3 times/week), 30.7% had chronic insomnia without daytime consequences, and 28.6% had chronic insomnia with daytime dysfunction. Indian ethnicity, age ≥50, anxiety symptoms, and depression symptoms were risk factors for chronic insomnia with daytime dysfunction.[ 16 ]

This study also analyzed the association of various comorbidities with insomnia and showed statistically significant correlation with patients having diabetes mellitus. In a similar study, Taylor et al .[ 4 ] demonstrated that people with chronic insomnia reported more of the following than did people without insomnia: Heart disease (21.9% vs. 9.5%), high blood pressure (43.1% vs. 18.7%), neurologic disease (7.3% vs. 1.2%), breathing problems (24.8% vs. 5.7%), urinary problems (19.7% vs. 9.5%), chronic pain (50.4% vs. 18.2%), and gastrointestinal problems (33.6% vs. 9.2%). Conversely, people with the following medical problems reported more chronic insomnia than did those without those medical problems: Heart disease (44.1% vs. 22.8%), cancer (41.4% vs. 24.6%), high blood pressure (44.0% vs. 19.3%), neurologic disease (66.7% vs. 24.3%), breathing problems (59.6% vs. 21.4%), urinary problems (41.5% vs. 23.3%), chronic pain (48.6% vs. 17.2%), and gastrointestinal problems (55.4% vs. 20.0%). When all medical problems were considered together, only patients with high blood pressure, breathing problems, urinary problems, chronic pain, and gastrointestinal problems had statistically higher levels of insomnia than those without these medical disorders.

Insomnia was also considered as a predictor for other sleep disorders such as obstructive sleep apnea in some studies.[ 17 ] A recent study done in Singapore illustrated that many patients with chronic insomnia have underlying primary sleep disorders.[ 18 ] Our study did not consider evaluating for other sleep disorders due to practical difficulties in doing sleep studies in primary care settings.

The perception of patients regarding insomnia was also significantly low in our study. A survey among adult French population in 2001–2002 regarding insomnia found that 25% of randomly selected respondents were dissatisfied with their sleep and only 13% had consulted a health-care provider, especially for insomnia.[ 19 ] In the South Indian study quoted above, only 2.2% people perceived themselves as having sleep-related problems.[ 7 ] In the study on Indian population in West Bengal, it was found that 43.2% of insomniac patients never seek medical advice for insomnia and only 15.3% actually consulted a doctor for their sleep problem.[ 8 ] In our population, no patient had actually presented with insomnia as their primary complaint, but 27% of insomniacs did not perceive their condition.

Insomnia is the most commonly encountered sleep disorder and occurs in 10%–50% of the population according to studies conducted worldwide. The pathophysiology of insomnia can actually be somewhat complex (or at least multi-factorial) because of the many inputs to the sleep-wake system in general and the additional specific behaviors and cognitions which an individual layers on top of the physiologic substrates.[ 20 ]

Studies show that insomnia negatively affects work performance, impairs decision-making, can damage relationships, increase chances of work-related/motor vehicle accidents,[ 21 ] and lead to overall decline in quality of life. Despite the prevalence of poor sleep quality and insomnia in the general population, people with sleep problems often go unnoticed in the health-care system. GPs were identified as the most frequently consulted group for sleep disorders.[ 19 ]

Insomnia can be classified as acute and chronic/primary and secondary.[ 22 , 23 , 24 ] When insomnia lasts for 4 weeks or more, it is classified as chronic insomnia.[ 2 ] It is further subclassified into with or without comorbidities (medical and psychiatric) and associated with another primary sleep disorder.[ 25 ] Numerous self-report instruments exist for the assessment of sleep disturbance. Among them, the most widely used are Pittsburgh Sleep Quality Index, Epworth sleepiness scale, Athens Insomnia Score, and Insomnia Severity Index.

Athens Insomnia Scale was chosen for this study because of its simple language, ease of questions and calculation, effectiveness, and reprint rights.[ 26 , 27 ]

This study showed a prevalence of chronic insomnia in 33% in the sample population surveyed, with females being more affected compared to males but in statistically insignificant values. There was a significant prevalence in patients having diabetes irrespective of the duration of diabetes and drugs taken. Increasing age was also a significant contributor to insomnia in adults. There was no major correlation with education/social/economic factors and comorbid conditions such as hypertension, asthma, migraine, heart diseases, and liver or kidney diseases.

There is also poor knowledge and awareness about sleep disorders and their health-related negative consequences in our population.

Insomnia is a common sleep disorder which is many times missed by a primary care physician until/unless asked for; the prevalence of which was as high as 33% in this study. Diabetes and increasing age were significantly associated with insomnia. Hence, all diabetic patients should be screened for insomnia by the primary care physician/diabetologist with a self-assessed questionnaire. A caring physician should assess the sleep pattern of every patient and give adequate counseling or treatment for the same.

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Conflicts of interest.

There are no conflicts of interest.