Sleep Initiation and Maintenance Disorders: Ohayon MM

Ohayon MM. · No affiliation provided · J Psychiatr Res. · Pubmed #17709046 No free full text.

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Ohayon MM. · No affiliation provided · Sleep. · Pubmed #16268370 No free full text.

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Ohayon MM, Shapiro CM. · No affiliation provided · J Psychosom Res. · Pubmed #12127167 No free full text.

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Poyares D, Guilleminault C, Ohayon MM, Tufik S. · Disciplina de Medicina e Biologia do Sono, Departamento de Psicobiologia da Universidade Federal de São Paulo, Brazil. · J Psychiatr Res. · Pubmed #15003439 No free full text.

Abstract: We studied the sleep of patients with insomnia during continuous and very long-term use of benzodiazepines (BZDs), and after withdrawal. A group of 25 patients (mean age 44.3+/-11.8 years) with persistent insomnia, who had been taking BZDs nightly for 6.8+/-5.4 years was selected. The control group was comprised of 18 age-matched healthy individuals. Sleep stage parameters were analyzed during Night 1 (while taking BZDs), Night 2 (first night after completing BZD withdrawal), and Night 3 (15 days after gradual BZD withdrawal). Sleep data for control subjects was monitored in parallel. Sleep EEGs of the patients were analyzed using Period Amplitude Analysis (PAA), during Nights 1 and 3 only. During BZD use, a significant reduction of Total Sleep Time (TST) and increased sleep latency were found in the insomniac group when compared to controls. We found an increase in stage 2 non-REM (NREM) sleep, and a reduction in Slow Wave Sleep (SWS) when comparing to night 3 (after withdrawal). Sleep EEGs analysis showed an increase in sigma band and decrease in delta count in stages 2, 3, 4 NREM and REM sleep in the BZD group when comparing to night 3 (after withdrawal). During the BZD withdrawal period, six out of nine subjects taking lorazepam failed withdrawal. In the remaining 19 subjects, gradual withdrawal of BZDs was associated with immediate worsening of nocturnal sleep, as indicated by sleep parameters. However, 15 days after withdrawal (Night 3), some of the sleep structure parameters of patients were not significantly different from baseline (while taking BZDs), except for a significant increase in SWS and in delta count throughout most sleep stages, and a decrease in stage 2 NREM sleep. These values were not different from those shown by control subjects. REM sleep parameters showed no significant variation across the experimental conditions. Subjective sleep quality was significantly improved on Night 3 compared with Night 1. Conclusions: Chronic intake of BZDs may be associated with poor sleep in this population. A progressive 15-day withdrawal did not avoid an immediate worsening of sleep parameters. But at the end of the protocol, SWS, delta count, and sleep quality were improved compared to those recorded during the chronic BZD intake, despite the lack of change in sleep efficiency.

Poyares DR, Guilleminault C, Ohayon MM, Tufik S. · Sleep Laboratory of the Department of Psychobiology, Universidade Federal de São Paulo, São Paulo, Brazil. · Prog Neuropsychopharmacol Biol Psychiatry. · Pubmed #11999905 No free full text.

Abstract: PURPOSE: The authors studied the sleep of patients with insomnia who complained of poor sleep despite chronic use of benzodiazepines (BZDs). The sample consisted of 19 patients (mean age 43.3+/-10.6 years) with primary insomnia (DSM-IV), who had taken BZDs nightly, for 7.1+/-5.4 years. The control group was composed of 18 healthy individuals (mean age 37+/-8 years). Sleep electroencephalogram (EEG) of the patients was analyzed with period amplitude analysis (PAA) and associated algorithms, during chronic BZD use (Night 1), and after 15 days of a valerian placebo trial (initiated after washout of BZD, Night 2). Sleep of control subjects was monitored in parallel. RESULTS: Valerian subjects reported significantly better subjective sleep quality than placebo ones, after BZD withdrawal, despite the presence of a few side effects. However, some of the differences found in sleep structure between Night 1 and Night 2 in both the valerian and placebo groups may be due to the sleep recovery process after BZD washout. Example of this are: the decrease in Sleep Stage 2 and in sigma count; the increase in slow-wave sleep (SWS), and delta count, which were found to be altered by BZD ingestion. There was a significant decrease in wake time after sleep onset (WASO) in valerian subjects when compared to placebo subjects; results were similar to normal controls. Nonetheless, valerian-treated patients also presented longer sleep latency and increased alpha count in SWS than control subjects. CONCLUSIONS: The decrease in WASO associated with the mild anxiolytic effect of valerian appeared to be the major contributor to subjective sleep quality improvement found after 2-week of treatment in insomniacs who had withdrawn from BDZs. Despite subjective improvement, sleep data showed that valerian did not produce faster sleep onset; the increase in alpha count compared with normal controls may point to residual hyperarousabilty, which is known to play a role in insomnia. Nonetheless, we lack data on the extent to which a sedative drug can improve alpha sleep EEG. Thus, the authors suggest that valerian had a positive effect on withdrawal from BDZ use.

Ohayon MM. · Stanford Sleep Epidemiology Research Center, Stanford University School of Medicine, 3430 West Bayshore Road, Stanford, Palo Alto, CA 94303, USA. · J Psychiatr Res. · Pubmed #18374943 No free full text.

Abstract: OBJECTIVE: Nocturnal awakenings are one of the most prevalent sleep disturbances in the general population. However, little is know about how its severity affects co-morbidity with mental disorders and organic diseases. METHODS: A representative sample consisting of 8937 non-institutionalized individuals aged 18 or over living in Texas, New York and California states were interviewed by telephone. The interviews included sleeping habits, health, sleep and mental disorders. Nocturnal awakenings were evaluated according to their frequency per week and per night, their duration and the motive(s) for the awakenings. RESULTS: A total of 35.5% of the sample reported awakening at least 3 nights per week: 23% of reported awakening at least one time every night; 4.5% 5 or 6 nights per week and 7.9% 3 or 4 nights per week. Nocturnal awakenings increased with age only among people with nightly awakenings and were more frequent among women than men only among those awakening every night. More than 90% of subjects reported this problem lasted for more than 6 months. About 40% of subjects with nocturnal awakenings also reported other insomnia symptoms. Generally speaking, organic diseases and psychiatric disorders were more frequent among subjects waking up at least 3 nights per week regardless the frequency of nocturnal awakenings. However, nightly nocturnal awakenings were associated with more frequent organic diseases, obesity and psychiatric disorders. CONCLUSIONS: Nocturnal awakenings disrupt the sleep of about one third of the general population. Nocturnal awakenings are associated with a wide variety of organic diseases and psychiatric disorders that warrant appropriate treatment.

Ohayon MM. · Stanford Sleep Epidemiology Research Center, Stanford University School of Medicine, 3430 W. Bayshore Road, Palo Alto, CA 94303, USA. · Arch Intern Med. · Pubmed #16801508 links to  free full text

Abstract: BACKGROUND: Because hot flashes can occur during the night, their presence has been frequently associated with insomnia in women with symptoms of menopause. However, many factors other than hot flashes or menopause can be responsible for insomnia, and several factors associated with insomnia in the general population are also commonly observed in perimenopausal and postmenopausal women who have hot flashes. METHODS: A random sample of 3243 subjects (aged > or =18 years) representative of the California population was interviewed by telephone. Included were 982 women aged 35 to 65 years. Women were divided into 3 groups according to menopausal status: premenopause (57.2%), perimenopause (22.3%), and postmenopause (20.5%). Hot flashes were counted if they were present for at least 3 days per week during the last month and were classified as mild, moderate, or severe according to their effect on daily functioning. Chronic insomnia was defined as global sleep dissatisfaction, difficulty initiating sleep, difficulty maintaining sleep, or nonrestorative sleep, for at least 6 months. Diagnoses of insomnia were assessed according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, classification. RESULTS: Prevalence of hot flashes was 12.5% in premenopause, 79.0% in perimenopause, and 39.3% in postmenopause. Prevalence of chronic insomnia was reported as 36.5% in premenopause, 56.6% in perimenopause, and 50.7% in postmenopause (P<.001). Prevalence of symptoms of chronic insomnia increased with the severity of hot flashes, reaching more than 80% in perimenopausal women and postmenopausal women who had severe hot flashes. In multivariate analyses, severe hot flashes were significantly associated with symptoms and a diagnosis of chronic insomnia. Poor health, chronic pain, and sleep apnea were other significant factors associated with chronic insomnia. CONCLUSIONS: Severe hot flashes are strongly associated with chronic insomnia in midlife women. The presence of hot flashes should be systematically investigated in women with insomnia. Treating hot flashes could improve sleep quality and minimize the deleterious consequences of chronic insomnia.

Guilleminault C, Kirisoglu C, Poyares D, Palombini L, Leger D, Farid-Moayer M, Ohayon MM. · Stanford Sleep Disorders Clinic, Stanford, CA 94305, USA. · J Psychiatr Res. · Pubmed #16473570 No free full text.

Abstract: This prospective study aimed to assess symptomatic evolution of patients diagnosed with Upper Airway Resistance Syndrome (UARS) four and half years after the initial UARS diagnosis. For this purpose, 138 UARS patients were contacted by mail between 43 and 69 months after the initial evaluation; 105 responded to the letter and 94 patients accepted to undergo new clinical and polysomnographic evaluations. Initial and follow-up polysomnographic recordings were scored using the same criteria. RESULTS: Of the 94 patients who completed the follow-up examination, none of them were using nasal CPAP. It was related to refusal by insurance providers to provide equipment based on initial apnea-hypopnea index (AHI) in 90/94 subjects. Percentage of patients with sleep related-complaints significantly increased over the four and half year period: daytime fatigue, insomnia and depressive mood increased by 12 to 20 times. Reports of sleep maintenance sleep onset insomnia and depressive mood was significantly increased. Hypnotic, antidepressant and stimulant prescription increased from initial to follow-up visit (from 11.7% to 61.7%; from 3.2% to 25.5% and from 0% to 9.6%, respectively) with antidepressant given as much for sleep disturbance as mood disorder. The polysomnography results at follow-up showed that 5 subjects had AHI compatible with Obstructive Sleep Apnea Syndrome (OSAS) but overall, respiratory disturbance index had no significant change. Total sleep time was significantly reduced compared to initial visit. CONCLUSIONS: Many UARS patients remained untreated following initial evaluation. Worsening of symptoms of insomnia, fatigue and depressive mood were seen with absence of treatment of UARS.

Ohayon MM, Vecchierini MF. · Stanford Sleep Epidemiology Research Center, Stanford University School of Medicine, 3430 W. Bayshore Road, Palo Alto, CA 94303, USA. · Sleep. · Pubmed #16218081 No free full text.

Abstract: STUDY OBJECTIVES: To present normative data of sleep-wake characteristics and to examine risk factors associated with extreme values (i.e., in the 5 lower and upper percentiles of the distribution) in older adults. DESIGN: Cross-sectional telephone survey SETTING: The metropolitan area of Paris, France. PARTICIPANTS: A total of 7010 randomly selected households were contacted. Among them, 1264 households included at least 1 resident 60 years of age or older; 1026 subjects agreed to participate (participation rate: 80.9%). INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Subjects were interviewed with the Sleep-EVAL System about their sleeping habits and sleep and psychiatric disorders. In addition, the system administered to all the participants the Psychological General Well-Being Schedule, the Cognitive Difficulties Scale (Mac Nair-R), and an independent living scale. The median nighttime sleep duration was 7 hours without significant difference between the age groups. Factors positively associated with the 5 percentile (4 hours 30 minutes or less) of nighttime sleep duration were obesity, poor health, insomnia, and insomnia accompanied by daytime sleepiness and cognitive impairment. At the other extremity (95th percentile), long sleep (9 hours 30 minutes or more) was associated with organic disease, lack of physical exercise, and lower education. A daytime sleep duration of 1 hour or more (95th percentile) was associated with being a man, cognitive impairment, high blood pressure, obesity, and insomnia. Long sleep latency (95th percentile at 80 minutes) was associated with anxiety, lower education, poor health, insomnia without excessive daytime sleepiness, and obstructive sleep apnea syndrome. Obesity and loss of autonomy in activities of daily living was associated with both early (9 PM or earlier) and late bedtime (1 AM or later) and early (< or = 5 AM) and late (> or = 9 AM) wake-up time. CONCLUSIONS: This study illustrates the usefulness of normal distributions of sleep parameters in the general population to calculate different risk factors associated with extreme values of the normal distribution.

Ohayon MM, Paiva T. · Stanford Sleep Epidemiology Research Center, Stanford University School of Medicine, Stanford, CA, USA. · Sleep Med. · Pubmed #16085459 No free full text.

Abstract: BACKGROUND AND PURPOSE: This study examines the prevalence and associated factors of insomnia symptoms and sleep dissatisfaction in the general population of Portugal. PATIENTS AND METHODS: We interviewed by telephone 1858 participants aged 18 years or older and representative of the general population of Portugal using the Sleep-EVAL system. Participation rate was 83%. The questionnaire included the assessment of sleep habits, insomnia symptomatology according to DSM-IV and ICSD classifications, associated and sleep/mental disorders and daytime consequences. RESULTS: Insomnia symptoms occurring at least 3 nights per week were reported by 28.1% of the sample and global sleep dissatisfaction (GSD) by 10.1%. Difficulty maintaining sleep was the most frequent symptom (21.0%); 29.4% of subjects with insomnia symptoms reported GSD. Daytime consequences, medical consultations for sleep and use of sleep medication were at least 2 times more frequent among subjects with insomnia symptoms and GSD compared to subjects with insomnia symptoms without GSD; insomnia diagnoses were also more frequent in the GSD group. CONCLUSIONS: The results show a severity gradation among subjects with only 1 insomnia symptom, those with 2 or 3 insomnia symptoms but without GSD and those with at least 1 insomnia symptom and GSD. Specific sleep or psychiatric disorders were identified for the majority of GSD subjects (86%); this rate dropped to 50.6% when only 1 insomnia symptom without GSD was reported. GSD appeared to be a good indicator of the presence of a sleep or psychiatric disorder and a good discriminator of the severity of sleep disturbances among subjects with insomnia symptoms.

Guilleminault C, Kirisoglu C, Ohayon MM. · Sleep Disorders Clinic, Stanford University, Stanford, CA 94305, USA. · Sleep. · Pubmed #15683141 No free full text.

Abstract: STUDY OBJECTIVES: Over a 2-month period, to evaluate serum levels of C-reactive protein (CRP) in new patients with obstructive sleep apnea syndrome (OSAS), upper airway resistance syndrome (UARS), and absence of important comorbidity, as well as in normal controls. DESIGN: Cross-sectional analysis. SETTING: Sleep disorders clinic. PATIENTS: 239 successively monitored subjects: 156 subjects were diagnosed with OSAS, 39 with UARS, and 54 controls. INTERVENTIONS: none. MEASUREMENTS AND RESULTS: Clinical information (neurologic, general medical, and otolaryngology examination), body mass index, neck circumference, hip-waist ratio, Epworth Sleepiness Scale, 3 fatigue scales, Sleep Disorders Questionnaire, serum CRP, and polysomnography were collected. Analysis of variance indicated a significant difference between the groups for diastolic blood pressure, respiratory disturbance index, lowest SaO2, and body mass index. The mean serum CRP level was normal in all 3 groups. Only 15 (14 OSAS and 1 UARS) out of 239 subjects had high serum CRP values. CRP levels were significantly correlated with body mass index, esophageal pressures, hip-waist ratio, neck circumference, and blood pressure. Only body mass index was significantly associated with high CRP values; multiple regression showed: adjusted R2 = 0.115, beta = 0.345, P <.001. When men and women were considered separately, body mass index was again significantly associated with high CRP levels. CONCLUSION: Obesity is a risk factor for high serum CRP levels in patients with sleep-disordered breathing, as in the general population.

Ohayon MM. · Stanford Sleep Epidemiology Research Center, Stanford University School of Medicine, Stanford, Calif., USA. · Arch Intern Med. · Pubmed #15642872 links to  free full text

Abstract: BACKGROUND: Nonrestorative sleep (NRS) has been little studied in the general population, even though this symptom has an important role in several medical conditions such as heart disease, fibromyalgia, and chronic fatigue syndrome, as well as various sleep disorders. METHODS: A total of 25,580 individuals (age range, 15-100 years) from the noninstitutionalized general population representative of 7 European countries (France, the United Kingdom, Germany, Italy, Portugal, Spain, and Finland) were interviewed by telephone using the Sleep-EVAL system. Nonrestorative sleep was analyzed in relationship to sociodemographic determinants, environmental factors, life habits, health, sleep-wake schedule, and psychological factors. RESULTS: The prevalence of NRS was 10.8% (95% confidence interval, 10.4%-11.2%) in the sample, was higher in women than in men (12.5% vs 9.0%; P<.001), and decreased with age. The United Kingdom (16.1%) and Germany (15.5%) had the highest prevalence of NRS and Spain (2.4%), the lowest. In multivariate analyses, several factors were positively associated with NRS. The most important were younger age, dissatisfaction with sleep, difficulty getting started in the morning, stressful life, presence of anxiety, bipolar or a depressive disorder, and having a physical disease. When compared with subjects who have difficulty initiating or maintaining sleep (without NRS), subjects with NRS reported more frequently a variety of daytime impairment (irritability, physical, and mental fatigue) and consulted a physician twice as frequently for their sleeping difficulties than did other subjects with insomnia. CONCLUSIONS: Nonrestorative sleep is a frequent symptom in the general population, but its prevalence largely varies between countries. It is often associated with mental disorders and characteristics of sleep deprivation (such as extra sleep time on weekends). Nonrestorative sleep affected more frequently the active classes of the population and caused greater daytime impairment than difficulty initiating or maintaining sleep.

Ohayon MM. · Stanford Sleep Epidemiology Research Center, School of Medicine, Stanford University, 3430 W. Bayshore Road, Suite 102, Palo Alto, Stanford, CA 94303, USA. · J Psychiatr Res. · Pubmed #15589563 No free full text.

Abstract: BACKGROUND: A chronic painful physical condition (CPPC) can be a major cause of sleep disturbances. Few community-based surveys examined the specific relationship between these two conditions. METHODS: Eighteen thousand, nine hundred and eighty participants aged 15 years or older from five European countries (the United Kingdom, Germany, Italy, Portugal and Spain) and representative of approximately 206 millions Europeans were interviewed by telephone. The interview included questions about sleeping habits, health, sleep and mental disorders. Painful physical conditions were ascertained through questions about medical treatment, consultations and/or hospitalizations for medical reasons and a list of 42 diseases. A painful physical condition was considered chronic when it lasted at least six months. Insomnia symptoms were defined as difficulty initiating or maintaining sleep or non-restorative sleep, present at least three nights per week, lasting at least one month, and accompanied by daytime consequences. RESULTS: (1) The point prevalence of at least one CPPC was set at 17.1% (95% CI: 16.5-17.6%) in the sample. (2) Difficulty initiating sleep was found in 5.1% (95% CI: 4.8-5.4%) of the sample, disrupted sleep in 7.5% (95% CI: 7.2-7.9%); early morning awakenings in 4.8% (95% CI: 7.2-7.9%) and non-restorative sleep in 4.5% (95% CI: 4.2-4.8%). (3) More than 40% of individuals with insomnia symptoms reported at least one CPPC. (4) CPPC was associated with more frequent difficulty or inability to resume sleep once awake and a shorter sleep duration. (5) In middle-aged subjects (45-64 years of age), CPPC was associated with longer insomnia duration. At any age, insomnia with CPPC was associated with a greater number of daytime consequences (average of four consequences) than in insomnia without CPPC (average of 2.3 consequences). (6) In multivariate models, CPPC, especially backaches and joint/articular diseases, were at least as importantly associated with insomnia than were mood disorders with odds ratios ranging from 4.1 to 5.0 for backaches and from 3.0 to 4.8 for joint/articular diseases. CONCLUSIONS: CPPC is associated with a worsening of insomnia on several aspects: a greater number of insomnia symptoms, more severe daytime consequences and more chronic insomnia situation. CPPC plays a major role on insomnia. Its place as major contributive factor for insomnia is as much important as mood disorders.

Ohayon MM, Lemoine P. · Stanford Sleep Epidemiology Research Center, School of Medicine, Stanford University, Stanford, California 94303, USA. · Encephale. · Pubmed #15235519 No free full text.

Abstract: Insomnia is a frequent symptom in the general population; numerous studies have proven this. In the past years, classifications have gradually given more emphasis to daytime repercussions of insomnia and to their consequences on social and cognitive functioning. They are now integrated in the definition of insomnia and are used to quantify its severity. If the daytime consequences of insomnia are well known at the clinical level, there are few epidemiological data on this matter. The aim of this study was to assess the daytime repercussions of insomnia complaints in the general population of France. A representative sample (n=5,622) aged 15 or older was surveyed by telephone with the help of the sleep-EVAL expert system, a computer program specially designed to evaluate sleep disorders and to manage epidemiological investigations. Interviews have been completed for 80.8% of the solicited subjects (n=5,622). The variables considered comprised insomnia and its daytime repercussions on cognitive functioning, affective tone, daytime sleepiness and diurnal fatigue. Insomnia was found in 18.6% of the sample. The prevalence was higher in women (22.4%) than in men (14.5%, p<0.001) with a relative risk of 1.7 (95% confidence interval 1.5 to 2) and was twice more frequent for subjects 65 years of age or older compared to subjects younger than 45 years. Approximately 30% of subjects reporting insomnia had difficulties initiating sleep. Nearly 75% of insomnia complainers reported having a disrupted sleep or waking up too early in the morning and about 40% said they had a non-restorative sleep. Repercussions on daytime functioning were reported by most insomnia subjects (67%). Repercussions on cognitive functioning changed according age, number of insomnia symptoms and the use of a psychotropic medication. A decreased efficiency was more likely to be reported by subjects between 15 and 44 years of age (OR: 2.9), those using a psychotropic (OR: 1.5), those reporting at least three insomnia symptoms (OR: 1.4) and women (OR: 1.4). The highest probability of the appearance of concentration difficulties was found in subjects younger than 65 Years, having a depressive disorder and using a psychotropic (15-44 years: OR 19.1; 45-64 years: OR 46.6). Difficulties maintaining attention were 15 times higher in subjects aged between 45 and 64 who were using a psychotropic and had also a depressive disorder. Memory difficulties were three times more likely to be reported by subjects using a psychotropic. At the affective level, irritability was 10 times more likely to be reported by subjects younger than 65 Years who were also using a psychotropic and had a depressive disorder. Independent of the presence of a mental disorder and the use of a psychotropic, subjects between 15 and 44 Years were five times more likely to be irritable following a bad sleep. Feeling depressed after a bad night's sleep was 18 times more likely to occur in subjects aged between 45 and 64 who were using a psychotropic and had a depressive disorder. Feeling anxious after a bad night's sleep was seven times more likely to occur in subjects with a depressive disorder. Daytime sleepiness was reported by approximately 20% of insomnia subjects. This rate was relatively comparable among gender, age groups, presence/absence of a mental disorder and use or not of a psychotropic. However, taking into account the interaction between age, use of a psychotropic and the presence of a mental disorder, subjects younger than 65 years, using a psychotropic and having a depressive disorder were at least 10 times more likely to report daytime sleepiness. Subjects who were suffering the most diurnal symptoms of insomnia were those younger than 65 years. Several factors can be evoked to explain this fact. These subjects were, for the most part, likelier to have a stricter sleep/wake schedule because of constraints imposed by work, studies, child care, etc. Subjects older than 65 Years were generally retired and therefore less prone to sleepiness and to cognitive difficulties. Insomnia consequences were limited due to their inactivity. Complementary studies should be undertaken to describe the daytime repercussions of insomnia for this specific age group of the general population and to measure these repercussions.

Ohayon MM, Lemoine P. · Stanford Sleep Epidemiology Research Center, School of Medicine, Stanford University, Stanford, California 94303, USA. · Encephale. · Pubmed #15107715 No free full text.

Abstract: Several epidemiological surveys performed in Western Europe reported a prevalence of insomnia symptoms between 20% and 40% of the general population. Women and elderly individuals were the most affected. Many events can occur during sleep and affect its quality. Daytime sleepiness, a consequence of lack of sleep and/or insomnia, is responsible for many road, work and domestic accidents. Therefore, insomnia may have important consequences both for individuals and society. This study performed in the non institutionalized French population reports the sleep habits of that population and the factors associated with insomnia. This epidemiological study was conducted with 5,622 subjects representative of the French general population. They were aged between 15 and 96 Years. The participation rate was 80.8%. The results showed that men and women have different sleep habits. Generally speaking, women went to bed about 12 minutes earlier than men and woke up later than men (p<0.001). Women also took more time to fall asleep than men but only when they were aged between 35 and 65 Years. Furthermore, women had a longer sleep than men except between the ages of 55 and 74, where men slept significantly more than women. However, sleep efficiency was lower in women than in men who were over age 35. This was due to a greater frequency of nocturnal awakenings in women than in men. Sleep habits also changed with age: Bedtime became progressively earlier with advancing age and wake-up time was later when the subjects reached retirement age. Sleep latency progressively increased with age after 35. Similarly, disrupted sleep increased with age and was reported by more than half of subjects 75 years or older. We found also that evening or night workers showed irregularities in their sleep patterns: sleep latency was significantly longer - at least 12 minutes - compared to daytime and shift workers (p<0.001). They also had a shorter sleep duration of about 30 minutes compared to shift workers, and 40 minutes compared to daytime workers (p<0.001). Shift workers and evening or night workers had a lower sleep efficiency compared to daytime workers. Finally, in regions with greater density population (>100,000 inhabitants) sleep duration was shorter by approximately 10 minutes compared to localities with fewer than 5,000 residents (p<0.01). Similarly, bedtime and wake up hours were more related in regions with more than 100,000 inhabitants compared to small localities (fewer than 5,000 residents). Insomnia complaints, defined as the presence of at least one insomnia symptom accompanied by sleep dissatisfaction or use of a sleep medication, were reported by 18.6% of the sample. The prevalence was higher in women (22.4%) than in men (14.5%) and increased with age. However, the proportion of subjects dissatisfied with their sleep remained comparable for all age groups; it was the number of subjects using a sleep medication that increased with age. This was 3.2% in subjects 44 years or younger, 13.3% in subjects between 45 and 64 years, 22% of those between 65 and 74 years and almost a third of individuals 75 Years or older (32%; p<0.001). However, insomnia symptoms remained present for most of these consumers: 80.4% of those between 15 and 44 years, 87.9% of those between 45 and 64 Years, 81.4% of those between 65 and 74 years and 78.8% of subjects of 75 years or older. Compared to subjects in other epidemiological studies undertaken in England, Germany and Italy and using the same methodology, subjects in this study complained with their sleep more often. Insufficient sleep was found more often in the active population, which is subject to schedule constraints. Shift workers as well as evening or night workers were the most likely to have a sleep debt.

Ohayon MM. · Sleep Disorders Center, Stanford University School of Medicine, Stanford, CA 94305, USA. · Sleep Med Rev. · Pubmed #12531146 No free full text.

Abstract: Epidemiologists have published more than 50 studies of insomnia based on data collected in various representative community-dwelling samples or populations. These surveys provide estimates of the prevalence of insomnia according to four definitions: insomnia symptoms, insomnia symptoms with daytime consequences, sleep dissatisfaction and insomnia diagnoses. The first definition, based on insomnia criteria as defined by the DSM-IV, recognizes that about one-third of a general population presents at least one of them. The second definition shows that, when daytime consequences of insomnia are taken into account, the prevalence is between 9% and 15%. The third definition represents 8-18% of the general population. The last definition, more precise and corresponding to a decision-making diagnosis, sets the prevalence at 6% of insomnia diagnoses according to the DSM-IV classification. These four definitions of insomnia have higher prevalence rates in women than in men. The prevalence of insomnia symptoms generally increases with age, while the rates of sleep dissatisfaction and diagnoses have little variation with age. Numerous factors can initiate or maintain insomnia. Mental disorders and organic diseases are the factors that have been the most frequently studied. The association between insomnia and major depressive episodes has been constantly reported: individuals with insomnia are more likely to have a major depressive illness. Longitudinal studies have shown that the persistence of insomnia is associated with the appearance of a new depressive episode. Future epidemiological studies should focus on the natural evolution of insomnia. Epidemiological genetic links of insomnia are yet to be studied.

Ohayon MM, Roth T. · Stanford Epidemiology Sleep Research Center, Stanford University, 401 Quarry Road Suite 3301, School of Medicine, Stanford, CA 94305, USA. · J Psychiatr Res. · Pubmed #12482465 No free full text.

Abstract: BACKGROUND: Insomnia is frequent in the general population and is often related to a psychiatric illness. However, little is known about how the chronicity of insomnia affects this relation and how often subjects with chronic insomnia have antecedents of psychiatric disorders. METHODS: A total of 14,915 subjects aged from 15 to 100 years representative of the general population of the United Kingdom, Germany, Italy, and Portugal were interviewed by telephone using the Sleep-EVAL system. The questionnaire assessed current psychiatric disorders according to the DSM-IV classification and a series of questions assessed the psychiatric history. Insomnia was considered as chronic when it lasted for 6 months or more. RESULTS: The prevalence for insomnia accompanied with impaired daytime functioning was 19.1% and significantly increased with age. More than 90% of these subjects had a chronic insomnia. About 28% of subjects with insomnia had a current diagnosis of mental disorders and 25.6% had a psychiatric history. A DSM-IV insomnia disorder was found in 6.6% of the sample. Presence of severe insomnia, diagnosis of primary insomnia or insomnia related to a medical condition, and insomnia that lasted more than one year were predictors of a psychiatric history. In most cases of mood disorders, insomnia appeared before (> 40%) or in the same time (> 22%) than mood disorder symptoms. When anxiety disorders were involved, insomnia appeared mostly in the same time (>38%) or after (> 34%) the anxiety disorder. CONCLUSIONS: The study shows that psychiatric history is closely related to the severity and chronicity of current insomnia. Moreover, chronic insomnia can be a residual symptom of a previous mental disorder and put these subjects to a higher risk of relapse.

Ohayon MM, Partinen M. · Stanford Sleep Epidemiology Research Center, School of Medicine, Stanford University, Stanford, CA, USA. · J Sleep Res. · Pubmed #12464102 No free full text.

Abstract: The purpose of this study is to assess the prevalence of insomnia symptoms and diagnoses in the general population of Finland. A total of 982 participants, aged 18 years or older and representative of the general population of Finland, were interviewed by telephone using the Sleep-EVAL system. The participation rate was 78%. The questionnaire included the assessment of sleep habits, insomnia symptomatology according to Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) and International Classification of Sleep Disorders (ICSD), associated and sleep/mental disorders and daytime consequences. The overall prevalence of insomnia symptoms occurring at least three nights per week was 37.6%. Difficulty initiating sleep were mentioned by 11.9% of the sample, difficulty maintaining sleep by 31.6%, early morning awakenings by 11.0% and non-restorative sleep by 7.9% of the sample. Global dissatisfaction with sleep was found in 11.9% of the sample. Daytime consequences (fatigue, mood changes, cognitive difficulties or daytime sleepiness) were reported by 39.9% of participants with insomnia symptoms and 87.6% of those with sleep dissatisfaction. A deterioration of sleep in summer or winter was associated with more complaints of sleep dissatisfaction. Prevalence of any DSM-IV insomnia diagnosis was 11.7%. More specifically, DSM-IV diagnosis of primary insomnia had a prevalence of 1.6% and DSM-IV diagnosis of insomnia related to another mental disorder was at 2.1%. Insomnia was a symptom of another sleep disorder in about 16% of cases and of a mental disorder in about 17% of cases. As reported in other Nordic studies, sleep quality was worse in summer. Insomnia symptomatology was common and was reported by more than a third of Finnish participants. Compared with other European countries studied with the same methodology (France, the UK, Germany, and Italy), the prevalence of DSM-IV insomnia diagnosis was 1.5 to two times higher in Finland.

Ohayon MM, Lemoine P. · Stanford Sleep Epidemiology Research Center, School of Medicine, Stanford University, Stanford, California, USA. · Encephale. · Pubmed #12386543 No free full text.

Abstract: Untreated insomnia often has repercussions on socio-professional or cognitive functioning of insomniacs. In industrialized countries, the prevalence of insomnia ranges between 10% and 48%, depending on the methodology and the measured time interval. However, few studies have examined the relationship between insomnia and mental disorder diagnoses. This epidemiological study on insomnia complaints was conducted on 5 622 subjects representative of the non-institutionalized French population aged 15 years or over. Sixteen interviewers using the Sleep-EVAL expert system performed telephone interviews. Insomnia complaints (defined as difficulty initiating or maintaining sleep, feeling unrefreshed at awakening accompanied by dissatisfaction with sleep quality or quantity, or use of sleep-promoting medication) were observed in 18.6% (95% confidence interval: 17.6% to 19.6%) of the sample. The median duration of insomnia complaints was five years. Regional variations in the prevalence of insomnia complaints were observed in France. In North 2 and Center 4 regions, the prevalence of insomnia complaints was higher compared to the rest of France with a relative risk of 1.4 (95% confidence interval: 1.1-1.6) time superior for the North region and 1.3 (95% CI: 1.0-1.6) for the Center 4 region. The lowest prevalence was registered in the Mediterranean area. In most regions, the prevalence of insomnia complaints was higher in women than in men with the exception of the South and West regions where the prevalence was similar. Subjects with insomnia complaints consulted more frequently compared to the rest of sample with an odds ratio of 3 to 1 [95% CI: 2.8 to 4.1]. Close to 20% of subjects were being treated for a physical disease at the time of the survey; subjects with insomnia complaints being twice more numerous (34.3%) than the rest of the sample (15.9%; p<0.001). To identify the main factors associated with insomnia complaints, socio-demographic and health variables were introduced in a multivariate model. Separated or divorced individuals (OR: 1.6); widowers (OR: 1.5); subjects aged between 45 and 65 years (OR: 1.4) or older than 65 (OR: 1.5); women (OR: 1.3); those with little or no education (OR: 1.4); and subjects living in the North region had higher reported insomnia complaints. Living in the East region (Mediterranean) was a protective factor (OR: 0.6). Furthermore, subjects with vascular diseases (OR: 2.0), musculo-skeletal diseases (OR: 2.0) or cardiac diseases (OR: 1.9) and those who had consulted a physician in the previous six months (OR: 2.7) had higher a probability of insomnia complaints. Subsequently, DSM IV insomnia diagnoses were examined in subjects who complained of insomnia. A diagnosis of primary insomnia was found in 7% of these subjects. A diagnosis of insomnia related to another mental disorder was found in 15.6% of insomnia complainers. A depressive disorder diagnosis was given in 10.8% of cases (mainly a major depressive disorder). This diagnosis was made more often among women and subjects of less than 65 years. An anxiety disorder diagnosis was given for 33.1% of insomnia complainers (an anxiety generalized disorder in about half the cases). About a quarter of insomnia complainers did not receive a diagnosis. This was the case more often for men and the subjects 65 years or older. If demographic and medical factors are relatively well documented at the epidemiological level, it is otherwise for psychiatric diagnosis associated with insomnia complaint. Very few studies in the general population have been done and still fewer of them have applied a positive and differential diagnosis process. In this study, we used the DSM IV classification to establish positive and differential diagnoses among subjects with insomnia complaints. Compared to other epidemiological studies, our study is distinguished by several aspects: 1) insomnia complaint had a narrower definition. It did not suffice that the subject reported insomnia symptoms, it was also necessary that the subject said s/he was dissatisfied with her/hr/his sleep or that s/he took measures to improve it (medication or sleep hygiene). This choice was motivated essentially by the fact that it is difficult, from a point of clinical point of view, to consider that an individual has insomnia solely based on the presence of symptoms, that, appreciated by a clinician, would resemble insomnia without that they make problem for the subject. 2) Several sleep habits were systematically collected. The majority of epidemiological studies are not centered on sleep problems, with the consequence that results do not allow a global view of factors that are associated with insomnia. 3) The various diagnostic categories of insomnia as well as elements of the differential diagnosis were applied. Thus, we can conclude that insomnia, as a diagnostic entity, including all its forms, is found in 5.6% of the French population. In the majority of cases, the insomnia complaint is part of the symptomatology of a mental disorder, mainly an anxiety disorder. This distinction is important since it helps the physician to determine therapeutic choices. To conclude, it is worthwhile to consider the number of insomnia complainers who had consulted a physician, mainly a general practitioner, in the six months prior to the study. This designates physicians as the first-line resource in the treatment and the prevention of sleep disorders.

Ohayon MM, Hong SC. · Stanford Sleep Epidemiology Research Center, School of Medicine, Stanford University, Suite 3301, 401 Quarry Road, Stanford, CA 4305, USA. · J Psychosom Res. · Pubmed #12127177 No free full text.

Abstract: INTRODUCTION: In Western countries, insomnia is associated with daytime impaired functioning, as well as physical and psychiatric illnesses. However, little information exists on insomnia in Asian countries. This study investigates the prevalence and correlates of insomnia in the general population of South Korea. METHODS: A representative sample of the South Korean general population composed of 3719 noninstitutionalized individuals aged 15 years or older were interviewed by telephone using the Sleep-EVAL system. The participation rate was 91.4%. The interviews covered sleep habits, sleep symptomatology, physical and psychiatric illnesses. DSM-IV sleep and psychiatric disorder diagnoses were also assessed. RESULTS: Insomnia symptoms occurring at least three nights per week were reported by 17.0% of the sample; difficulty initiating sleep (DIS) was mentioned by 4.0% of the sample, difficulty maintaining sleep (DMS) by 11.5%, early morning awakenings (EMA) by 1.8%, and nonrestorative sleep (NRS) by 4.7% of the sample. DSM-IV insomnia disorder diagnoses were found in 5% of the sample. Over 50% of subjects with insomnia symptoms reported important daytime consequences and another 20% reported mild or moderate consequences. However, the proportion of insomnia subjects seeking medical help for their sleep problems was very low (6.8%). CONCLUSIONS: As in Western countries, insomnia is widespread in South Korea, affecting nearly one in five individuals. Many of them would benefit from medical help; however, few insomnia subjects are consulting for this problem. An educational effort is needed for both the general population and the physicians.

Ohayon MM. · Stanford Sleep Epidemiology Research Center, School of Medicine, Stanford University, 401, Quarry Road Suite 3301 Stanford, California, 94305 USA. · Encephale. · Pubmed #12091782 No free full text.

Abstract: The study of sleep disorders in the general population involves several methodological issues that need to be defined prior to proceeding to the epidemiological study. The rigor of the methodology is an important issue since it will determine the reliability of the data gathered. This paper describes the methodology used in an epidemiological study performed in the French general population using telephone interviews with the help of Sleep-EVAL, an expert system designed for this purpose. The study aimed to investigate the prevalence of insomnia disorders according to the DSM IV classification and the use of psychotropic medications in the general population. The methodological choices for this study were based on several considerations. First, the sample had to be representative of the French population. Second, the study had to be conducted in the shortest period of time. Third, the interviews had to be conducted with respect to a strict standardization and fourth, the realization costs had to be minimal for a maximum of data collected. The telephone interview procedure was chosen over postal and face-to-face interviews because it offered the possibility of conducting all the interviews from the same site. Supervision was easier. It also offered an absolute control in the application of the selection procedure. To draw the sample, a two-stage procedure was adopted. At the first stage, we pulled a random series of telephone numbers in each Nielsen region with respect to the size of the settlement. At the second stage, during the initial telephone contact, a household member was chosen using the Kish selection procedure. This method is based on the utilization of eight tables of selection that allows for the choice of the person to interview in a given household and keeps the representativeness of the sample. This technique is little used in telephone surveys because of its burden and its intrusive nature: the interviewer must collect the age and gender of all eligible subjects, to classify men from the oldest to youngest and then to classify women. However, it is the most rigorous selection method for epidemiological surveys. To reduce the refusal rates and to alleviate the work of interviewers, the Kish method was implanted in the computer software used for this study. For this study, the exclusion criteria were minimal. Only individuals younger than 15 years of age, those with a speech or hearing impairment and those who were too ill to perform the interview were not included. Subjects who refused to participate, those who hung up without speaking to the interviewer and those who hung up before completing at least half of the interview were tabulated as refusal. The participation rate was calculated by dividing the number of completed interviews by the number of eligible participants (completed interviews, refusals and telephone numbers where the interviewer was unable to determine if the individuals met an exclusion criterion). In this study, the participation rate was 80.8% (5 622 completed interviews/6 966 eligible households). The diagnostic tool used for this study was the Sleep-EVAL system, an expert system designed to conduct epidemiological studies in the general population. It is a level 2, non-monotonic system endowed with a causal reasoning able to provide sleep and mental disorders diagnoses according to the DSM IV classification for this study. Subsequent versions of Sleep-EVAL also included the International Classification of Sleep Disorders. System symbolic representation of the classifications was put in a compiled knowledge base. This knowledge base was read and interpreted by the inference engine at the beginning of the interview. During the interview, this interpretation changed as a function of the answers provided by the interviewee and by deductions made from the analysis of information the system already knew. All interviews began with a standard questionnaire about sociodemographic information and sleep habits. From these first answers, the Sleep-EVAL system emitted a series of diagnostic hypotheses that were confirmed or rejected with supplementary questions. The interview ended once all diagnostic possibilities were exhausted. The validity of the Sleep-EVAL system was demonstrated in different studies performed in sleep disorders clinics. There were several advantages in using such a tool to conduct epidemiological surveys. No special skills from the interviewers nor specific knowledge of sleep and mental disorders were required. All the questions were chosen and formulated by the Sleep-EVAL system. The interviewer had simply to read the questions as they appeared on the monitor screen and enter the interviewee's responses by clicking the appropriate answer or typing it on the keyboard. Missing answers were non-existent because there was no possibility of skipping a question or entering inconsistent answers. It also ensured the uniformity of the interviews. Furthermore, it allowed the exploration of infrequent diagnoses. In summary, the methodology used for this study allowed for the investigation of the sleep pathology of the French population in a short period of time: only three months were necessary to complete the 5 622 interviews. The use of a computerized tool greatly facilitated the training of the interviewers and also their work. Furthermore, it ensured a standardized administration of the interviews and the exploration of a broad range of disorders that could hardly be realized with traditional paper-pencil questionnaires.

Ohayon MM, Roth T. · Stanford Sleep Epidemiology Research Center, Stanford University School of Medicine, Suite 3301, 401 Quarry Road, Stanford, CA 94305, USA. · J Psychosom Res. · Pubmed #11750297 No free full text.

Abstract: Lack of a systematic assessment of insomnia has led to large variations in its reported prevalence in the general population. This study aims to provide new guidelines to assess insomnia prevalence. A cross-sectional telephone survey using the Sleep-EVAL system was done with 24,600 general population-based subjects 15 years and older representative of general populations (France, the UK, Germany, Italy, Portugal, and Spain) consisting of 251,405,391 inhabitants. The overall participation rate was 81.0%. Within the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) symptomatology for insomnia, 27.2% (95% confidence interval: 26.6-27.8%) of the sample reported difficulty initiating sleep (DIS) (10.1%) or maintaining sleep (DMS) (disrupted sleep (DS): 18.0%; early morning awakening (EMA): 10.9%) or nonrestorative sleep (NRS) (8.9%) at least three times per week; 48.5% of them were concomitantly suffering of a DSM-IV sleep/mental disorder. A factor analysis identified several variables strongly related to each of the major factors of insomnia allowing: (1) The narrowing of the definition of insomnia: the prevalence of insomnia decreased to 16.8% with 64.5% of insomnia subjects having a DSM-IV sleep/mental disorder; (2) The identification of a sleep-deprived (voluntary or not) group without insomnia symptoms, representing 2.1% (1.9-2.3%) of the sample. Interestingly, the latter group closely matched the definition of insufficient sleep syndrome as described by the International Classification of Sleep Disorders (ICSD). Using more delineated criteria to assess insomnia increases the recognition of subjects complaining about sleep. Classifications should be amended to improve the correct identification of insomnia. Sleep-deprived subjects should also not be neglected.

Ohayon MM, Zulley J. · Stanford Sleep Epidemiology Reseach Center, School of Medicine, Stanford University, California 94305, USA. · Sleep. · Pubmed #11683481 No free full text.

Abstract: STUDY OBJECTIVES: Global sleep dissatisfaction (GSD) is not part of the habitual insomnia symptoms in epidemiological studies. Furthermore, none of these studies has examined the relative importance of the various factors correlated to sleep dissatisfaction. This study aims to examine the links between GSD and insomnia and to find the factors contributing to GSD. DESIGN: A cross-sectional telephone survey was conducted in Germany (66 million inhabitants 15 years of age or older) with a representative sample of 4,115 subjects aged 15 years or older. Interviewers used the Sleep-EVAL system. The questionnaire covered several topics that were grouped into six classes of variables identified as potential factors associated with sleep dissatisfaction: sociodemographic descriptors, environmental factors, life habits, health status, psychological factors, sleep/wake factors. SETTING: N/A. PARTICIPANTS: A representative sample of 4,115 subjects aged 15 years or older INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Overall, 7% of the subjects reported being GSD; 95.5% of them had at least one insomnia symptom. The duration of insomnia symptom(s) was 20 months longer in GSD subjects compared to insomnia subjects without GSD. The prevalence of GSD was higher in women than in men and increased with age. The most significant predictive factors for GSD were: 1) for sleep/wake schedule variables: night sleep duration less than 6 hours (OR: 4.0 and over) and sleep latency greater than 30 minutes. 2) for sociodemographic variables: age between 65 and 74 (OR: 6.7) 3) for health variables: Upper airway disease (OR: 7.1); 4) for mental health variables: anxiety symptoms (OR: 3.0); 5) for environmental factors: too hot bedroom (OR=2.5) 6) for life habit factors: the need of a particular object in order to fall asleep (OR: 2.4). CONCLUSIONS: This study confirms that GSD is a better indicator of an underlying pathology than the classical insomnia symptoms alone: compared to insomniac subjects without GSD, subjects with GSD were two times more likely to report excessive daytime sleepiness, and eight times more likely to have a diagnosis of sleep or mental disorder. Furthermore, in car drivers, road accidents in the previous year were two times more frequent with GSD drivers as compared to insomnia drivers without GSD. Subjects with GSD were more than 10 times more likely to seek help for their sleep problems and five times more likely to use a sleep medication than insomnia subjects without GSD.

Ohayon MM, Zulley J, Guilleminault C, Smirne S, Priest RG. · Stanford University School of Medicine, Sleep Disorder Center, California 94305, USA. · J Am Geriatr Soc. · Pubmed #11347777 No free full text.

Abstract: OBJECTIVES: To determine the role of activity status and social life satisfaction on the report of insomnia symptoms and sleeping habits. DESIGN: Cross-sectional telephone survey using the Sleep-EVAL knowledge base system. SETTING: Representative samples of three general populations (United Kingdom, Germany, and Italy). PARTICIPANTS: 13,057 subjects age 15 and older: 4,972 in the United Kingdom, 4,115 in Germany, and 3,970 in Italy. These subjects were representative of 160 million inhabitants. MEASUREMENTS: Clinical questionnaire on insomnia and investigation of associated pathologies (psychiatric and neurological disorders). RESULTS: Insomnia symptoms were reported by more than one-third of the population age 65 and older. Multivariate models showed that age was not a predictive factor of insomnia symptoms when controlling for activity status and social life satisfaction. The level of activity and social interactions had no influence on napping, but age was found to have a significant positive effect on napping. CONCLUSIONS: These results indicate that the aging process per se is not responsible for the increase of insomnia often reported in older people. Instead, inactivity, dissatisfaction with social life, and the presence of organic diseases and mental disorders were the best predictors of insomnia, age being insignificant. Healthy older people (i.e., without organic or mental pathologies) have a prevalence of insomnia symptoms similar to that observed in younger people. Moreover, being active and satisfied with social life are protective factors against insomnia at any age.

Ohayon MM, Roberts RE, Zulley J, Smirne S, Priest RG. · Sleep Disorders Center, Stanford University School of Medicine, CA 94305, USA. · J Am Acad Child Adolesc Psychiatry. · Pubmed #11128333 No free full text.

Abstract: OBJECTIVE: Despite many constraints on time schedules among teenagers, epidemiological data on sleep complaints in adolescence remain limited and are nonexistent for sleep disorders. This study provides additional data on sleep habits and DSM-IV sleep disorders in late adolescence. METHOD: A representative sample of 1,125 adolescents aged 15 to 18 years was interviewed by telephone using the Sleep-EVAL system. These adolescents came from 4 European countries: France, Great Britain, Germany, and Italy. Information was collected about sociodemographic characteristics, sleep/wake schedule, sleep habits, and sleep disorders and was compared with information from 2,169 young adults (19-24 years of age). RESULTS: Compared with young adults, adolescents presented with a distinct sleep/wake schedule: they went to sleep earlier, they woke up later, and they slept longer than young adults did. On weekends and days off, they also slept more than young adults did. However, the prevalence rates of sleep symptoms and sleep disorders were comparable in both groups. Approximately 25% reported insomnia symptoms and approximately 4% had a DSM-IV insomnia disorder. Fewer than 0.5% had a circadian rhythm disorder. CONCLUSIONS: Prevalence of insomnia disorders is lower in the adolescent population than in middle-aged or elderly adults. However, a rate of 4% in this young population is important given their young age and the consequences for daytime functioning.