The Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5; American Psychiatric Association, 2013) contains 10 sleep-wake disorders: insomnia; hypersomnolence; narcolepsy; breathing related; circadian rhythm; non-rapid eye movement (NREM) sleep arousal; nightmare; rapid eye movement (REM) sleep behaviour; restless legs syndrome; and substance/medication-induced sleep difficulties. The DSM-5 nosology incorporates recent advances in our understanding of the physiological and genetic factors underpinning disordered sleep, the impact of lifespan development on sleep and pathology, and findings from treatment studies. Diagnostic formulations incorporate validated polysomnographic and neurobiologic biomarkers, which distinguish the diagnosis of sleep from most other psychiatric disorders. Unfortunately, it is not possible to review all 10 DSM-5 sleep-wake disorders in one summary chapter. As a result, this chapter will focus on those most often addressed via psychological interventions. Readers interested in a review of the full range of sleeping disorders are referred to the companion academic supplementary materials available for the current textbook.
Common to all the DSM-5 sleep-wake disorders is dissatisfaction with the quality, timing, and amount of sleep, together with evidence of impact or distress in everyday functioning. Diagnosis also depends on the sleep problem being primary in origin and not secondary to a known medical condition, disease, or health impairment. However, identifying the primary disorder can be complicated by the bidirectional and often mutually exacerbating relationship that exists between disordered sleep (e.g., insomnia, excessive sleepiness, early morning wakefulness) and many psychiatric and medical conditions. Sleep problems typically do not occur in isolation, but there is good evidence that treating sleep disorders can lead to gains, even when secondary to other medical problems.
Two distinguishing features of the sleep disorders field are: 1. the diversity of disorders; and 2. the degree to which psychological treatments play a role in therapy. Some sleep disorders are more properly addressed via medical and pharmaceutical interventions, such as narcolepsy with stimulant medication and obstructive sleep apnoea hypopnea disorder with continuous positive airway pressure (CPAP) apparatus, although cognitive behaviour therapy (CBT) has been shown to increase CPAP adherence (Agudelo et al., 2014; Richards et al., 2007).