Hypersomnolence Disorders

Despite varied classification systems, hypersomnolence disorders (or central disorders of hypersomnolence) are a group of disorders with a common symptom of excessive daytime sleepiness. In addition to a thorough clinical interview and examination, the assessment of hypersomnolence may require clinical investigations such as polysomnography and the multiple sleep latency test. This chapter examines the disorders of hypersomnolence with an emphasis on their clinical features and treatment strategies. The authors discuss the four main types of hypersomnolence disorders, narcolepsy type 1, narcolepsy type 2, idiopathic hypersomnia and Kleine–Levin syndrome, as well as hypersomnia due to a medical disorder, medication, or substance use; a psychiatric disorder; and insufficient sleep syndrome. It also discusses the relationships between hypersomnolence and psychiatric disorders.

Future of Sleep Medicine and Psychiatry

As evidenced throughout this volume, sleep and psychiatry are deeply intertwined. Sleep and psychiatric processes share multiple biologic underpinnings, and sleep and psychiatric disorders are highly comorbid, with an additive adverse impact. Yet, much remains unknown, and much work remains to optimize treatments of sleep disorders in psychiatric populations. This chapter is to consider these issues with an eye toward the future. The chapter briefly considers sleep medicine education in psychiatry, drug development and novel compounds, consumer wearables, behavioral and complementary approaches, telehealth, and sleep health economics. The authors argue for the need to a value-based approach to sleep and psychiatry.

Breathing-Related Sleep Disorders

Breathing-related sleep disorders (BRSD) encompass obstructive sleep apnea (OSA), central sleep apnea, and hypoventilation disorders. Risk factors for BRSD include obesity, metabolic dysfunction, smoking, use of respiratory depressant medications (like opiates and benzodiazepines), and alcohol consumption, all of which are highly prevalent among patients with psychiatric disorders. BRSDs are associated with substantial morbidity, disturbed quality of life, and worse prognosis of comorbid psychiatric disorders. Therefore, it is essential for psychiatric care providers to have the clinical skills to recognize BRSDs. Recent studies suggest that the prevalence rates of OSA in psychiatric patients are higher than the general population. Moreover, BRSD’s share common symptoms and risk-factors with psychiatric disorders. A comprehensive clinical approach including a thorough sleep history and examination along with the use of validated screening questionnaires like the STOP-BANG questionnaire, particularly for at-risk patients, is effective in identifying BRSD.

Sleep-Related Movement Disorders

Sleep-related movement disorders include disorders that manifest as simple and mostly stereotyped movements occurring at sleep–wake interface or during sleep. Restless legs syndrome (RLS), the most common sleep-related movement disorder. RLS is a treatable condition that psychiatrists must be familiar with due to its common comorbidity with a broad range of psychiatric disorders. In addition, commonly used psychotropic medications are known to induce or worsen RLS symptoms in predisposed individuals, and these symptoms may be mistaken for akathisia or sleep-initiation insomnia and lead to mismanagement. This chapter discusses, among other RLS-related topics, the diagnosis, epidemiology, predisposing factors, genetic factors, and the role of iron metabolism.

Forensic Sleep Medicine

Patients with sleep disorders can exhibit behavior that includes violent acts. The behavior may occur during various sleep stages, ranges in complexity, and requires an analysis of consciousness. When the behavior harms another person and criminal charges follow, expert testimony will be required to explain the physiology of the disorder and impairments in consciousness that determine criminal culpability, that is, whether there was conscious intent behind the behavior. In this chapter, sleep-related conditions associated with violent behavior are discussed, along with guidelines for presenting scientific testimony in court. These disorders include rapid eye movement (REM) behavior disorder, somnambulism and other non-REM partial awakenings, and hypersomnolence. Feigned symptoms and malingering must be ruled out, and the clinical parameters for them are discussed. While the physiology of sleep disorders has widely been known, admissibility in court is not automatic. Standards for acceptable expert testimony are discussed.

Sleep and Cognition

How does sleep affect our brain functioning, and what happens when we do not receive our necessary “portion” of sleep? It is a well-known fact that sleep is essential for restoration of body and mind efficiency, while a lack of appropriate sleep adversely impacts mood, motor functions, and cognition, eventually affecting the quality of everyday life. Recent studies highlighted links between the amount of sleep disturbance and the severity of deterioration in some cognitive functions. Moreover, clinical observations indicate that sleep disturbances might be one of the earliest signs of neurodegenerative disorders, including early Alzheimer’s disease and dementia. This chapter briefly reviews the relationships between sleep and cognition, and consider the evidence suggesting that sleep deprivation and sleep disorders are associated with poor cognitive functioning and, in clinical population, with cognitive decline.

Anxiety, Obsessive-Compulsive, and Related Disorders

Despite its common comorbidity, sleep disturbance is often underrecognized and undertreated in individuals with anxiety disorders. Compared to mood disorders, sleep disturbance in this population is less well studied except for panic disorder and generalized anxiety disorder. Some evidence suggests a bidirectional link between anxiety disorders and sleep disturbance. Polysomnography findings point to some commonalities across anxiety disorders, including longer sleep onset latency, reduced total sleep time, and reduced sleep efficiency. The underlying biological mechanisms linking anxiety disorders and sleep disturbance are still unclear. However, there is limited evidence suggesting a connection between impaired executive functioning due to sleep problems and failure to inhibit anxiety related thoughts and feelings. Cortisol irregularities and disruption in the serotonergic system may also play a role. Evidence suggests that anxiety sensitivity is a transdiagnostic factor that contributes to both anxiety disorders and sleep disturbance. Further research is warranted to elucidate common biological and psychological factors underlying sleep disturbances and anxiety disorders. There is an imminent need to systematically assess the impact of sleep disturbance on symptom severity and treatment outcomes in anxiety, obsessive-compulsive, and related disorders. Limited evidence is available for medications and targeted psychotherapeutic interventions for management of sleep disturbance thus warranting the development of robust sleep interventions to achieve optimal clinical outcomes in this patient population.

Circadian Rhythms

Circadian rhythms are endogenous, near 24-hour oscillations that underlie nearly all facets of our health and behavior. The daily cycle of sleep and wake is the most conspicuous circadian-influenced behavior in humans. This chapter introduces the circadian rhythms in humans that give rise to our daily cycling of sleep and alertness, including their fundamental features and loci of origin. The interplay between circadian rhythms and sleep is discussed, including physiological and behavioral methods for the measurement of circadian rhythms. Finally, typical and atypical features of circadian rhythms in relation to health and aging are considered with particular reference to the impact of modern societal pressures.

Psychotropic Medications and Sleep

Psychiatric disorders, apart from impairing functioning during waking hours, also exert profound effects on sleep. The interventions used in treating these disorders can exert equally strong influences on sleep homeostasis. Pharmacologic agents that treat psychiatric disorders give rise to a broad range of effects on sleep, both beneficial and deleterious. This chapter reviews the available data on how sleep is affected by medications commonly used for the treatment of psychiatric disorders. While the focus will be on antidepressants, antiepileptic mood stabilizers, and antipsychotics, as these are the best studied medication classes in the psychiatric population, hypnotics and stimulants are also addressed. The authors focus, where available, on studies conducted in psychiatric populations.

Pharmacological Management of Insomnia

Insomnia has posed a management challenge for patients and clinicians for centuries. Historically, a variety of compounds have been utilized for the treatment of this common malady, with many of them associated with unwanted side effects. Over the past few decades, however, a variety of agents have emerged for treatment of insomnia with improved safety profiles. This chapter reviews these agents, with attention to their pharmacokinetic profile, mechanism of action, and other, clinically relevant characteristics. It also discusses a rational approach in the selection of each agent to optimize the treatment of insomnia. The chapter closes with a look toward the future of the pharmacological management of insomnia.