Other Specified Insomnia Disorder, as classified in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DMS-5-TR), is a sleep disorder characterized by significant difficulty in initiating or maintaining sleep. This disorder is distinct from other insomnia subtypes in the DMS-5-TR due to its unique diagnostic criteria and presentation. Individuals with Other Specified Insomnia Disorder often experience marked distress or impairment in social, occupational, educational, academic, behavioral, or other important areas of functioning due to sleep disturbance. The disorder is not attributable to the physiological effects of a substance or another medical or mental disorder (American Psychiatric Association [APA], 2023).

Patients with this disorder typically report a range of symptoms, including difficulty falling asleep, staying asleep, or experiencing non-restorative sleep. Unlike other forms of insomnia, this disorder is categorized explicitly under 'other specified' because it does not meet the full criteria for other insomnia disorders yet still causes significant distress or impairment in critical areas of functioning. This category is often used when the clinician needs to specify why the presentation does not meet the criteria for any specific insomnia disorder (APA, 2023).

For instance, a person may experience sleep disturbance predominantly due to conditioned arousal associated with the sleep environment or insomnia resulting from paradoxical insomnia (misperception of sleep). These presentations differ slightly from the more general patterns of insomnia and warrant a specific classification (Harvey, 2002).

Individuals suffering from Other Specified Insomnia Disorders often present in clinical settings with complaints about the quality, timing, and amount of sleep, which results in daytime fatigue and cognitive impairment such as diminished concentration or memory problems. These symptoms are often exacerbated by the worry and anxiety about sleep, creating a vicious cycle (Carney & Edinger, 2010).

In summary, Other Specified Insomnia Disorder in DMS-5-TR represents a distinct category of insomnia characterized by sleep difficulties leading to significant distress or impairment but not aligning entirely with other insomnia categories. This classification allows for a more tailored approach to understanding and treating individuals experiencing unique patterns of sleep disturbances.

Diagnostic Criteria

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DMS-5-TR), categorizes Other Specified Insomnia Disorder under sleep-wake disorders, providing specific criteria for its diagnosis. This disorder is characterized primarily by a predominant complaint of dissatisfaction with sleep quantity or quality, associated with one (or more) of the following symptoms: difficulty initiating sleep, difficulty maintaining sleep, early-morning awakening with an inability to return to sleep or non-restorative sleep. These sleep difficulties occur at least three nights per week and are present for at least three months.

Notably, the sleep disturbance causes clinically significant distress or impairment in social, occupational, educational, or other important areas of functioning. The sleep difficulty occurs despite adequate opportunity for sleep, and often, individuals with this disorder will report spending excessive time in bed trying to sleep, which paradoxically may perpetuate their insomnia (APA, 2023).

The "other specified" category is used when the clinician specifies why the presentation does not meet the criteria for any specific insomnia disorder. This could include conditions such as short sleep duration syndrome, where individuals regularly sleep less than four to five hours per night without the typical impairments associated with insomnia (Vgontzas et al., 2013).

In the DMS-5-TR (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition), "Other Specified Insomnia Disorder" is a category used when an individual's insomnia disorder does not meet the full criteria for any of the specific insomnia disorders but still causes significant distress or impairment. The specifiers for this disorder are used to provide additional detail and clarity about the nature of the insomnia experienced by the individual. These specifiers include:

• Short-Term Insomnia Disorder: This specifier is used when the individual's insomnia symptoms last less than three months. It is often associated with an identifiable stressor.
• Insomnia Due to Medical Condition: This specifier is applied when the insomnia is believed to be directly caused by another medical condition yet does not meet the full criteria for Insomnia Due to Another Medical Condition.
• Insomnia Nonrestorative Sleep: This specifier is for cases where the primary complaint is about nonrestorative sleep, meaning the individual feels that sleep is unrefreshing or of poor quality despite having a normal quantity and duration of sleep.
• Paradoxical Insomnia: Also known as "sleep state misperception," this is used when there is a significant discrepancy between the individual's perception of their sleep and objective measures, such as polysomnography. Individuals may report severe insomnia without evidence of substantial objective sleep disturbance.
• Behaviorally Induced Insufficient Sleep Syndrome: This specifier may be used when the insomnia is due to the individual's voluntary decision to limit the time allotted for sleep, leading to sleep deprivation.
• Insomnia With Non-Sleep Disorder Mental Comorbidity: This is used when insomnia occurs in the context of another mental disorder, like anxiety or depression, but does not meet the criteria for another more specific insomnia disorder.
• Other or Unspecified: This can be used when the specific nature of the insomnia does not fit neatly into the other categories or when there is insufficient information to make a more specific determination.

These specifiers allow clinicians to more accurately describe the nature of an individual's insomnia, facilitating more tailored treatment approaches. It is important to note that the choice of specifier depends on the predominant feature of the individual's insomnia as assessed by the clinician.

Research has shown that individuals with Other Specified Insomnia Disorder often exhibit higher levels of stress and anxiety about sleep, contributing to a heightened state of arousal that further disrupts sleep patterns (Harvey, 2002). Cognitive-behavioral therapy for insomnia (CBT-I) has been found effective in treating this disorder, highlighting the importance of addressing cognitive and behavioral aspects of sleep disturbance (Edinger et al., 2001).

In summary, Other Specified Insomnia Disorder is a complex sleep disorder requiring careful assessment and individualized treatment. Its inclusion in the DMS-5-TR highlights the diversity and complexity of sleep disorders, acknowledging that not all insomnia presentations fit neatly into predefined categories.

The Impacts

Other Specified Insomnia Disorder, as classified in the DMS-5-TR, has significant impacts on various aspects of an individual's life. Research has extensively documented the broad range of adverse effects associated with insomnia, which are also applicable to Other Specified Insomnia Disorder.

Cognitive Impairments: Individuals with insomnia often experience cognitive deficits, including problems with memory, attention, and executive function. Fortier-Brochu et al. (2012) found that individuals with insomnia reported more severe cognitive impairments, particularly in attention and memory, than good sleepers. These impairments are believed to result from the disruptive effects of poor sleep quality and quantity on brain function.

Mood Disturbances: There is a well-established link between insomnia and mood disorders, particularly depression and anxiety. A study by Baglioni et al. (2011) demonstrated that insomnia is a significant risk factor for the development of depression. The study found that individuals with persistent insomnia had a higher risk of developing depression compared to those without insomnia.

Physical Health Risks: Chronic insomnia is associated with various physical health issues. Vgontzas et al. (2013) found that insomnia with short sleep duration is linked to an increased risk of hypertension, diabetes, and obesity. This connection is thought to be due to the effects of poor sleep on hormonal balance, glucose metabolism, and inflammation.

Workplace and Academic Performance: Insomnia affects occupational and academic performance. Leger et al. (2014) reported that individuals with insomnia experienced more workplace accidents and errors and had lower productivity compared to those without sleep problems. Additionally, students with insomnia were found to have lower academic performance.

Quality of Life: Overall, insomnia significantly impacts the quality of life. A study by Kyle et al. (2010) indicated that individuals with insomnia reported lower quality of life scores, with particular difficulties in domains related to vitality, social functioning, and mental health.

In conclusion, Other Specified Insomnia Disorder can have far-reaching impacts on cognitive function, mood, physical health, productivity, and overall quality of life. These findings highlight the importance of recognizing and treating insomnia to mitigate these adverse effects.

The Etiology (Origins and Causes)

The etiology of Other Specified Insomnia Disorder, as categorized in the DMS-5-TR, is multifaceted and involves an interplay of biological, psychological, and environmental factors. Unlike other more specific sleep disorders, the causes of Other Specified Insomnia Disorder can vary widely based on the individual and the underlying reasons for their sleep disturbance.

Biological Factors: Evidence suggests that certain biological factors, including genetic predisposition, play a role in the development of insomnia. Drake et al. (2003) conducted a study that found a higher prevalence of insomnia in first-degree relatives of individuals with insomnia, indicating a potential genetic link. Additionally, alterations in the regulation of neurotransmitters and hormonal systems, particularly those related to the stress response, such as cortisol, have been implicated in insomnia (Riemann et al., 2010).

Psychological Factors: Psychological factors, including stress, anxiety, and depression, are strongly associated with insomnia. A study by Jansson-Fröjmark & Lindblom (2008) found that psychological stress and negative emotional states can precipitate or exacerbate insomnia. This relationship is often bidirectional, where insomnia can lead to increased stress and mood disturbances and vice versa.

Behavioral Factors: Behavioral factors contribute to insomnia, particularly poor sleep hygiene, and maladaptive sleep habits. These include irregular sleep schedules, engaging in stimulating activities before bedtime, and spending excessive time awake in bed. A study by Morin et al. (2006) highlighted the role of maladaptive coping strategies, such as spending too much time in bed, in the development and maintenance of insomnia.

Environmental Factors: Environmental factors such as noise, light, and temperature can also disrupt sleep. These factors may be particularly relevant in Other Specified Insomnia Disorder where the specific cause of insomnia does not fit neatly into other categories. Okamoto-Mizuno and Mizuno (2012) reviewed how bedroom environment and bedding can affect sleep quality.

Medical and Substance-Related Factors: Medical conditions, including chronic pain and respiratory disorders, can cause or worsen insomnia. Similarly, the use of certain medications or substances, such as caffeine and alcohol, can affect sleep patterns. A study by Roehrs and Roth (2001) examined the impact of substance use on sleep, highlighting how substances like alcohol and caffeine can significantly disrupt normal sleep architecture.

In summary, the etiology of Other Specified Insomnia Disorder is complex and multifactorial, involving a combination of biological, psychological, behavioral, and environmental factors. Understanding these various contributing factors is crucial for effective diagnosis and management.

Comorbidities

Other Specified Insomnia Disorder, as delineated in the DMS-5-TR, often coexists with a variety of comorbidities. These comorbidities can be psychological and physical, and they play a significant role in the complexity and management of the disorder.

Psychological Comorbidities: One of the most common comorbidities of insomnia is mental health disorders, particularly anxiety and depression. A study by Johnson et al. (2006) found a strong association between insomnia and major depressive disorder, with insomnia often preceding the onset of depression. Similarly, Taylor et al. (2005) reported a bidirectional relationship between insomnia and anxiety disorders, suggesting that not only can anxiety lead to insomnia, but insomnia can also increase the risk of developing anxiety disorders.

Physical Health Comorbidities: Insomnia is frequently comorbid with various physical health conditions. Chronic pain is a notable example, as elucidated in a study by Smith et al. (2001), which found that individuals with chronic pain syndromes frequently experience sleep disturbances. Moreover, insomnia has been linked with cardiovascular diseases. A longitudinal study by Laugsand et al. (2011) showed that insomnia symptoms were associated with an increased risk of acute myocardial infarction.

Neurological Disorders: There is evidence linking insomnia with certain neurological disorders. A study by Sieminski & Partinen (2016) highlighted the relationship between insomnia and restless legs syndrome, a neurological disorder characterized by an irresistible urge to move the legs.

Substance Use Disorders: The relationship between insomnia and substance use disorders is also well-documented. Brower et al. (2001) found that individuals with alcohol dependence often have insomnia, both as a symptom of their substance use and during periods of withdrawal.

Respiratory Disorders: Respiratory disorders, such as asthma and chronic obstructive pulmonary disease (COPD), have been associated with insomnia. A study by Budhiraja et al. (2012) reported that individuals with COPD often experience disrupted sleep patterns, contributing to the severity of insomnia.

These comorbidities highlight the necessity for a comprehensive approach to the diagnosis and treatment of Other Specified Insomnia Disorder. Understanding the interrelationships between insomnia and its comorbid conditions is crucial for effective management and treatment strategies.

Risk Factors

The risk factors for Other Specified Insomnia Disorder, as described in the DMS-5-TR, are multifaceted and can be categorized into environmental, physiological, psychological, and lifestyle-related factors.

Environmental Factors: One significant environmental risk factor for insomnia is exposure to noise and light during sleep. Ong et al. (2012) demonstrated that exposure to environmental noise and light pollution, especially in urban areas, can significantly disrupt sleep patterns and lead to insomnia.

Physiological Factors: Age and gender also influence the risk of developing insomnia. A study by Foley et al. (2004) found that the prevalence of insomnia increases with age, and women are more likely to develop insomnia than men. Hormonal changes, especially during menopause, have been identified as a contributing factor for higher insomnia rates in women.

Psychological Factors: Stress and mental health disorders are prominent psychological risk factors for insomnia. A study by Neckelmann et al. (2007) indicated that individuals with high levels of stress or mental health disorders like depression and anxiety are at a greater risk of developing insomnia. This relationship is often bidirectional, where insomnia can exacerbate or contribute to the development of mental health issues.

Lifestyle-Related Factors: Lifestyle choices, including irregular sleep schedules and substance use, are key risk factors for insomnia. A research article by Watson et al. (2013) highlighted that irregular sleep patterns, often influenced by work schedules or social commitments, can disrupt the body's circadian rhythm and lead to insomnia. Additionally, the use of stimulants like caffeine and nicotine, as well as alcohol, has been found to impact sleep quality significantly.

Genetic Factors: Although less is understood about the genetic predisposition to insomnia, a study by Barclay & Gregory (2013) suggested that there might be a genetic component to insomnia, with a higher prevalence observed in individuals who have a family history of sleep disorders.

In summary, the risk factors for Other Specified Insomnia Disorder are diverse and encompass a range of environmental, physiological, psychological, and lifestyle-related elements. These factors can individually or collectively contribute to the development and maintenance of insomnia.

Case Study

Background: Cory, a 24-year-old male, presented to the clinic with complaints of persistent sleep disturbances for approximately six months. He reported difficulties initiating and maintaining sleep despite having adequate opportunities and conditions for sleep. Cory stated that these issues had begun to affect his daily functioning, including his job performance and social interactions.

Clinical Presentation: Cory described spending hours in bed trying to fall asleep almost every night, often feeling anxious about not getting enough sleep. He reported frequently waking up at night and having trouble falling back asleep. Cory also mentioned feeling fatigued during the day, affecting his work concentration. He denied any significant life changes or stressors prior to the onset of his sleep problems.

Medical and Psychiatric History: Cory had no previous medical or psychiatric history. There was no reported use of medication, alcohol, or recreational drugs. His physical examination and routine blood tests were within normal limits. Cory denied any history of mental health disorders in his family.

Assessment and Diagnosis: Given the duration and nature of Cory's symptoms, he was assessed for insomnia. Standardized questionnaires, including the Insomnia Severity Index (ISI) and sleep diaries, were used to evaluate his sleep patterns and the impact of his symptoms on daytime functioning. The findings suggested that Cory's sleep difficulties met the criteria for Other Specified Insomnia Disorder as per DMS-5-TR. His insomnia was classified as 'Other Specified' due to its distinct presentation that did not fully align with other specific insomnia disorders.

Management and Treatment: Cory was referred to a sleep specialist for further evaluation. Cognitive Behavioral Therapy for Insomnia (CBT-I) was initiated, focusing on addressing Cory's anxiety related to sleep, establishing a regular sleep-wake schedule, and modifying maladaptive beliefs about sleep. He was also educated about sleep hygiene practices.

Follow-up: Over eight weeks, Cory reported a gradual improvement in his sleep quality and a reduction in the time taken to fall asleep. His ISI scores showed significant improvement, and he reported feeling less fatigued during the day. He also noticed an improvement in his concentration and overall mood. Cory was advised to continue practicing the strategies learned in CBT-I and maintaining good sleep hygiene.

Discussion: This case illustrates a typical presentation of Other Specified Insomnia Disorder in a young adult. The absence of underlying medical or psychiatric conditions and the distinctive nature of the insomnia symptoms guided the diagnosis. The case underscores the importance of a thorough assessment and the effectiveness of CBT-I in managing such sleep disorders. It also highlights the impact of insomnia on daily functioning and the potential for improvement with appropriate intervention.

Recent Psychology Research Findings

Research on Other Specified Insomnia Disorder, as delineated in the DMS-5-TR, has shed light on various aspects of this condition, from its prevalence and impact to treatment approaches.

Prevalence and Impact: Morin et al. (2006) investigated the prevalence of insomnia, including Other Specified Insomnia Disorder, in the general population. They found that many individuals experience symptoms consistent with this disorder. The study highlighted the substantial impact of insomnia on daily functioning, noting that those with insomnia reported higher levels of impairment at work, higher healthcare utilization, and a lower quality of life compared to individuals without insomnia.

Cognitive-Behavioral Therapy (CBT) for Insomnia: The effectiveness of CBT for treating Other Specified Insomnia Disorder has been a focus of recent research. A randomized controlled trial by Edinger et al. (2001) showed that CBT effectively reduced insomnia symptoms. The study demonstrated significant improvements in sleep latency, total sleep time, and sleep efficiency in participants who received CBT compared to those who received placebo or no treatment.

Impact of Technology on Sleep: With the increasing use of technology, its impact on sleep has become a relevant area of study. A research article by Cain and Gradisar (2010) explored the effects of screen time on sleep, particularly in younger populations. The study found a correlation between increased use of technology before bedtime and symptoms of insomnia, suggesting a potential risk factor for the development of sleep disorders.

Comorbid Psychological Disorders: The relationship between insomnia and psychological disorders has been extensively studied. A longitudinal study by Baglioni et al. (2011) examined the association between insomnia, particularly Other Specified Insomnia Disorder, and the development of depression. The study provided evidence that insomnia is a risk factor for the onset of depression, underscoring the need for early identification and treatment of sleep disorders.

Neurobiological Underpinnings: The neurobiological aspects of insomnia have also been a focus of research. Riemann et al. (2010) conducted a study exploring the brain mechanisms of insomnia. The study indicated abnormalities in brain activity, particularly in regions associated with sleep regulation, in individuals with insomnia. This research contributes to a deeper understanding of the biological basis of sleep disorders.

These studies collectively contribute to understanding Other Specified Insomnia Disorder, highlighting its prevalence, impact, and potential treatment strategies. They underscore the importance of recognizing and addressing this disorder in clinical practice.

Treatment and Interventions

The treatment and interventions for Other Specified Insomnia Disorder focus primarily on non-pharmacological approaches, with Cognitive Behavioral Therapy for Insomnia (CBT-I) being the most extensively studied and recommended treatment.

Cognitive Behavioral Therapy for Insomnia (CBT-I): CBT-I is a structured program that helps patients identify and replace thoughts and behaviors that cause or worsen sleep problems with habits that promote sound sleep. A landmark study by Edinger et al. (2001) demonstrated the efficacy of CBT-I in treating insomnia. The study involved a randomized controlled trial where participants receiving CBT-I showed significant improvements in sleep latency, duration, efficiency, and overall sleep quality compared to control groups. The therapy typically includes stimulus control, sleep restriction, cognitive restructuring, sleep hygiene education, and relaxation techniques.

Pharmacological Treatments: While not the first line of treatment for Other Specified Insomnia Disorder, medications can be used in some instances, especially when insomnia is severe or CBT-I is not available or effective. A study by Krystal et al. (2003) assessed the effectiveness of various pharmacological agents like benzodiazepines and non-benzodiazepine hypnotics. The study found that these medications could improve sleep latency and duration in the short term but cautioned about potential side effects and the risk of dependence.

Mindfulness and Relaxation Techniques: Techniques such as mindfulness meditation and progressive muscle relaxation are also used to manage insomnia. A study by Gross et al. (2011) found that mindfulness-based therapy for insomnia resulted in significant improvements in sleep quality. These techniques help reduce the hyperarousal often accompanying insomnia by promoting relaxation and non-judgmental awareness of thoughts and feelings.

Bright Light Therapy: Bright light therapy has been explored as a treatment for insomnia, particularly related to circadian rhythm disturbances. A study by Terman et al. (2001) demonstrated that exposure to bright light at specific times of the day could help reset the body's circadian clock, thereby improving sleep patterns in individuals with insomnia.

Lifestyle Modifications and Sleep Hygiene: Lifestyle changes and sleep hygiene practices are often recommended as part of a comprehensive treatment plan for insomnia. This includes maintaining a regular sleep schedule, creating a comfortable sleep environment, avoiding caffeine and alcohol before bedtime, and engaging in regular physical activity. A review by Stepanski and Wyatt (2003) emphasized the importance of these interventions in improving sleep quality and duration.

In conclusion, the treatment of Other Specified Insomnia Disorder is multifaceted, with CBT-I being the cornerstone of therapy. Pharmacological interventions, mindfulness and relaxation techniques, bright light therapy, and lifestyle modifications also play significant roles in managing this disorder.

Implications if Untreated

Untreated Other Specified Insomnia Disorder can have significant implications for an individual's physical and mental health, as well as their overall quality of life. Numerous studies have explored these implications, highlighting the critical need for timely and effective intervention.

Physical Health Implications: Chronic insomnia has been linked to various physical health problems. A study by Vgontzas et al. (2009) found that individuals with chronic insomnia exhibited increased inflammation markers, which are risk factors for hypertension and cardiovascular disease. Moreover, untreated insomnia has been associated with a higher risk of developing metabolic disorders, such as diabetes and obesity, as explored by Spiegel et al. (2005) in their research on sleep deprivation and hormonal imbalance.

Mental Health Implications: The link between insomnia and mental health disorders is well-documented. A longitudinal study by Baglioni et al. (2011) demonstrated that individuals with persistent insomnia have an increased risk of developing depression. Furthermore, insomnia is often comorbid with anxiety disorders, and the presence of insomnia can exacerbate these conditions, as noted in a study by Jansson-Fröjmark and Lindblom (2008).

Cognitive and Performance Implications: Insomnia adversely affects cognitive functions, including memory, attention, and executive function. A research article by Fortier-Brochu et al. (2012) highlighted significant cognitive impairments in individuals with chronic insomnia. Additionally, insomnia can lead to decreased work productivity and increased risk of accidents, as observed in a study by Leger et al. (2014) on the impact of sleep disorders in the workplace.

Quality of Life: Chronic insomnia can significantly reduce the overall quality of life. Kyle et al. (2010) found that individuals with insomnia reported lower quality of life scores, particularly in vitality, social functioning, and mental health.

In summary, untreated Other Specified Insomnia Disorder can lead to severe physical and mental health issues, impaired cognitive and workplace performance, and a diminished quality of life. These findings underscore the importance of recognizing and treating insomnia to mitigate its adverse effects.

Summary

Other Specified Insomnia Disorder presents significant challenges in both diagnosis and treatment, reflecting the complexity and evolving understanding of sleep disorders in clinical practice. Historically, insomnia was often viewed through a lens that emphasized its symptoms rather than its broader impact on an individual's life. Over time, perspectives have shifted to recognize insomnia as a multifaceted disorder with far-reaching implications, leading to more inclusive and compassionate approaches to diagnosis and treatment.

Diagnosing Other Specified Insomnia Disorder is challenging due to its heterogeneous nature. Unlike more straightforward insomnia subtypes, this disorder encompasses a variety of presentations that do not fully align with established categories. Research by Roth (2007) illustrated the evolving understanding of insomnia, showing how it is increasingly seen as a disorder that can exist independently of other conditions rather than just a symptom of other issues.

The impact of Other Specified Insomnia Disorder extends beyond mere sleep disruption. It can profoundly affect an individual's identity, relationships, and daily functioning. A study by Morin et al. (2006) highlighted that individuals with insomnia often experience feelings of frustration and helplessness, which can erode self-confidence and self-esteem. The strain of persistent sleep difficulties can also lead to tension in personal relationships as partners and family members struggle to understand and cope with the effects of the disorder.

In terms of daily life, the disorder's impact is substantial. Leger et al. (2014) noted that insomnia can lead to decreased concentration, memory problems, and increased risk of accidents, significantly affecting work performance and safety. The chronic nature of Other Specified Insomnia Disorder means that these effects can persist over time, leading to long-term consequences for an individual’s professional and personal life.

The historical evolution in understanding Other Specified Insomnia Disorder underscores the importance of a nuanced approach to sleep disorders. This perspective recognizes the complex interplay of biological, psychological, and social factors in insomnia and advocates for treatments that address these diverse aspects. Current approaches emphasize patient-centered care, focusing on improving overall well-being and quality of life rather than merely alleviating symptoms.

In summary, Other Specified Insomnia Disorder is a challenging condition with significant implications for an individual's mental and physical health, identity, relationships, and daily functioning. The evolution in understanding and treating this disorder reflects a more inclusive and compassionate approach, recognizing the profound impact of sleep on overall well-being.

References

Baglioni, C., Battagliese, G., Feige, B., Spiegelhalder, K., Nissen, C., Voderholzer, U., Lombardo, C., & Riemann, D. (2011). Insomnia as a predictor of depression: A meta-analytic evaluation of longitudinal epidemiological studies. Journal of Affective Disorders, 135(1-3), 10-19.

Barclay, N. L., & Gregory, A. M. (2013). Quantitative genetic research on sleep: A review of normal sleep, sleep disturbances and associated emotional, behavioural, and health-related difficulties. Sleep Medicine Reviews, 17(1), 29–40.

Brower, K. J., Aldrich, M. S., Robinson, E. A., Zucker, R. A., & Greden, J. F. (2001). Insomnia, self-medication, and relapse to alcoholism. American Journal of Psychiatry, 158(3), 399-404.

Budhiraja, R., Parthasarathy, S., Drake, C. L., Roth, T., Sharief, I., Budhiraja, P., & Saunders, V. (2012). Early CPAP use identifies subsequent adherence to CPAP therapy. Sleep, 35(3), 359–366.

Cain, N., & Gradisar, M. (2010). Electronic media use and sleep in school-aged children and adolescents: A review. Sleep Medicine, 11(8), 735-742.

Carney, C. E., & Edinger, J. D. (2010). Identifying and managing insomnia in primary care practice. Journal of Clinical Psychology in Medical Settings, 17(2), 31–43.

Drake, C. L., Roehrs, T., Richardson, G., Walsh, J. K., & Roth, T. (2003). Shift work sleep disorder: Prevalence and consequences beyond that of symptomatic day workers. Sleep, 26(8), 1014–1020.

Edinger, J. D., Wohlgemuth, W. K., Radtke, R. A., Marsh, G. R., & Quillian, R. E. (2001). Cognitive behavioral therapy for treatment of chronic primary insomnia: A randomized controlled trial. JAMA, 285(14), 1856-1864.

Foley, D., Ancoli-Israel, S., Britz, P., & Walsh, J. (2004). Sleep disturbances and chronic disease in older adults: Results of the 2003 National Sleep Foundation Sleep in America Survey. Journal of Psychosomatic Research, 56(5), 497–502.

Fortier-Brochu, É., Beaulieu-Bonneau, S., Ivers, H., & Morin, C. M. (2012). Insomnia and daytime cognitive performance: A meta-analysis. Sleep Medicine Reviews, 16(1), 83-94.

Gross, C. R., Kreitzer, M. J., Reilly-Spong, M., Wall, M., Winbush, N. Y., Patterson, R., Mahowald, M., & Cramer-Bornemann, M. (2011). Mindfulness-based stress reduction versus pharmacotherapy for chronic primary insomnia: A randomized controlled clinical trial. Explore, 7(2), 76-87.

Harvey, A. G. (2002). A cognitive model of insomnia. Behaviour Research and Therapy, 40(8), 869–893.

Jansson-Fröjmark, M., & Lindblom, K. (2008). A bidirectional relationship between anxiety dep,ression, and insomnia? A prospective study in the general population. Journal of Psychosomatic Research, 64(4), 443-449.

Johnson, E. O., Roth, T., & Breslau, N. (2006). The association of insomnia with anxiety disorders and depression: Exploration of the direction of risk. Journal of Psychiatric Research, 40(8), 700-708.

Krystal, A. D., Walsh, J. K., Laska, E., Caron, J., Amato, D. A., Wessel, T. C., & Roth, T. (2003). Sustained efficacy of eszopiclone over 6 months of nightly treatment: Results of a randomized, double-blind, placebo-controlled study in adults with chronic insomnia. Sleep, 26(7), 793–799.

Kyle, S. D., Morgan, K., & Espie, C. A. (2010). Insomnia and health-related quality of life. Sleep Medicine Reviews, 14(1), 69–82.

Laugsand, L. E., Vatten, L. J., Platou, C., & Janszky, I. (2011). Insomnia and the risk of acute myocardial infarction: A population study. Circulation, 124(19), 2073-2081.

Leger, D., Bayon, V., Ohayon, M. M., Philip, P., Ement, P., Metlaine, A., Chennaoui, M., & Faraut, B. (2014). Insomnia and accidents: Cross-sectional study (EQUINOX) on sleep-related home, work and car accidents in 5293 subjects with insomnia from 10 countries. Journal of Sleep Research, 23(2), 143-152.

Morin, C. M., Bootzin, R. R., Buysse, D. J., Edinger, J. D., Espie, C. A., & Lichstein, K. L. (2006). Psychological and behavioral treatment of insomnia: Update of the recent evidence (1998-2004). Sleep, 29(11), 1398-1414.

Morin, C. M., LeBlanc, M., Daley, M., Gregoire, J. P., & Merette, C. (2006). Epidemiology of insomnia: Prevalence, self-help treatments, consultations, and determinants of help-seeking behaviors. Sleep Medicine, 7(2), 123-130.

Neckelmann, D., Mykletun, A., & Dahl, A. A. (2007). Chronic insomnia as a risk factor for developing anxiety and depression. Sleep, 30(7), 873-880.

Okamoto-Mizuno, K., & Mizuno, K. (2012). Effects of thermal environment on sleep and circadian rhythm. Journal of Physiological Anthropology, 31(1), 14.

Ong, J. C., Arnedt, J. T., & Gehrman, P. R. (2012). Insomnia diagnosis, assessment, and evaluation. In M. L. Perlis & C. M. Morin (Eds.), Insomnia: Psychological assessment and management (pp. 3-19). Guilford Press.

Riemann, D., Baum, E., Cohrs, S., Crönlein, T., Hajak, G., Hertenstein, E., Klose, P., Langhorst, J., Pollmächer, T., Schutte-Rodin, S., Steiger, A., Voderholzer, U., & Winkelmann, J. (2010). S3-Leitlinie Nicht erholsamer Schlaf/Schlafstörungen. Somnologie, 14(Suppl 1), 1-160.

Riemann, D., Spiegelhalder, K., Feige, B., Voderholzer, U., Berger, M., Perlis, M., & Nissen, C. (2010). The hyperarousal model of insomnia: A review of the concept and its evidence. Sleep Medicine Reviews, 14(1), 19-31.

Roehrs, T., & Roth, T. (2001). Sleep, sleepiness, and alcohol use. Alcohol Research & Health, 25(2), 101-109.

Roth, T. (2007). Insomnia: Definition, prevalence, etiology, and consequences. Journal of Clinical Sleep Medicine, 3(5 Suppl), S7-S10.

Sieminski, M., & Partinen, M. (2016). Sleep disorders in Parkinson's disease. Sleep Disorders, 2016, 1-7.

Smith, M. T., Haythornthwaite, J. A., & Pigeon, W. R. (2001). The effects of sleep disturbance on patients with chronic pain. Pain Medicine, 2(4), 354–366.

Spiegel, K., Tasali, E., Penev, P., & Van Cauter, E. (2005). Brief communication: Sleep curtailment in healthy young men is associated with decreased leptin levels, elevated ghrelin levels, and increased hunger and appetite. Annals of Internal Medicine, 141(11), 846-850.

Stepanski, E. J., & Wyatt, J. K. (2003). Use of sleep hygiene in the treatment of insomnia. Sleep Medicine Reviews, 7(3), 215-225.

Taylor, D. J., Lichstein, K. L., & Durrence, H. H. (2005). Insomnia as a health risk factor. Behavioral Sleep Medicine, 1(4), 227-247.

Terman, M., Terman, J. S., Ross, D. C. (2001). A controlled trial of timed bright light and negative air ionization for treatment of winter depression. Archives of General Psychiatry, 58(10), 971-978.

Vgontzas, A. N., Fernandez-Mendoza, J., Liao, D., & Bixler, E. O. (2013). Insomnia with objective short sleep duration: The most biologically severe phenotype of the disorder. Sleep Medicine Reviews, 17(4), 241-254.

Vgontzas, A. N., Zoumakis, E., Bixler, E. O., Lin, H. M., Follett, H., Kales, A., & Chrousos, G. P. (2009). Adverse effects of modest sleep restriction on sleepiness, performance, and inflammatory cytokines. Journal of Clinical Endocrinology & Metabolism, 94(5), 1436-1443.

Watson, N. F., Badr, M. S., Belenky, G., Bliwise, D. L., Buxton, O. M., Buysse, D., Dinges, D. F., Gangwisch, J., Grandner, M. A., Kushida, C., Malhotra, R. K., Martin, J. L., Patel, S. R., Quan, S. F., & Tasali, E. (2013). Joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society on the recommended amount of sleep for a healthy adult: Methodology and discussion. Journal of Clinical Sleep Medicine, 11(8), 931-952.