The author reviews the role of sleep symptomatology in psychiatric disorders and sleep conditions that are associated with psychiatric disorders, including affective, anxiety, and psychotic disorders. Sleep disturbances are common in individuals who are experiencing psychiatric illness and are included in the diagnostic criteria of many of the affective and anxiety disorders. Sleep symptoms may hinder response to treatment and frequently persist after treatment of psychiatric conditions, increasing the risk of relapse or preventing full remission. Thus, clinical attention to sleep disturbances during acute and maintenance treatment of psychiatric conditions is important. The author discusses general treatments for the management of sleep disturbances experienced in the context of psychiatric illness, including cognitive behavioral therapy for insomnia and its effects on insomnia comorbid with psychiatric conditions. More recently, data support digital administration of cognitive behavioral therapy for insomnia when appropriate. Novel medications that target orexin are now being used as alternatives to more conventional agents.
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• Sleep problems can be “primary” conditions or “secondary” to other medical, substance-related, or psychiatric conditions.
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• Sleep disturbances found with psychiatric conditions may be secondary to the primary disorder, or part of the pathophysiology of the disorder.
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• The presence of sleep disturbance, such as insomnia, can complicate clinical course for patients with psychiatric illness.
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• Effective treatment of sleep disturbance comorbid with psychiatric illness can be accomplished using both pharmacological and nonpharmacological strategies.
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• Sleep disturbance often persists after successful treatment of depression.
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• Treatment of insomnia comorbid with depression can enhance treatment response to antidepressant medication.
Historical note and terminology
Sleep conditions can be “primary” conditions or “secondary” to another medical or psychiatric disorder. Sleep complaints associated with a psychiatric condition may be a result of the condition (poor sleep quality with a pain disorder) or part of the pathology of the condition (nightmares in posttraumatic stress disorder). Indeed, reciprocally changes in mood, anxiety, and cognition can result from sleep disturbances.
Sleep complaints have long been recognized as common in psychiatric disorders, but scientific study of the relationship between sleep and psychiatric disorders began with the introduction of polysomnography as a research and subsequent clinical tool in the 1960s.
Early sleep studies suggested that nocturnal dreaming was restricted to REM sleep, which had only recently been differentiated from other stages of sleep (25). Due to the centrality of dreams in psychoanalytic theory, psychotic hallucinations were thought to be caused by dreams somehow entering the waking state. However, gross intrusion of REM sleep during daytime hours was not observed in patients with schizophrenia. Similarly, nocturnal REM sleep patterns also did not intrude in patients as compared to healthy controls (74; 37).
In the late 1960s it was discovered that intrusion of REM sleep into waking life in the form of hypnagogic hallucinations, sleep paralysis, and cataplexy occurs in the condition of narcolepsy.
Kupfer first observed that a reduced latency from initial sleep onset to REM sleep onset (REM latency) could be demonstrated in major depression (47). This finding is not unique to depression but occurs also in schizophrenia (87), panic disorder (90), and perhaps other psychiatric illnesses. Sitaram and colleagues first suggested that centrally acting cholinergic agonists could induce short REM latency (83). An abnormal cholinergic mechanism may, therefore, be common to several severe mental illnesses. Much current work focuses on the role of central monoaminergic dysfunction in the pathogenesis of psychiatric disorders and the associated sleep disturbance.
The classification of psychiatric disorders as well as primary sleep disorders and their current diagnostic criteria are contained in the fifth edition text revision of the Diagnostic and Statistical Manual of Mental Disorders (03). Sleep conditions are also described in The International Classification of Sleep Disorders: Diagnostic and Coding Manual, 3rd edition (02).
In contrast to the preceding version, the DSM-5 does not distinguish between “primary” and “secondary” conditions, given the general limitations to assuming causality of symptoms and potential to undertreat the insomnia symptom in conditions other than idiopathic insomnia. Insomnia is instead characterizing the condition by its chronicity (81). Although the etiologies may differ, the treatment options are similar across conditions, noting that sleep problems in the context of another mental health condition necessitates treating the primary condition as well.