Parasomnias

Abstract

Parasomnias are undesirable and abnormal movements, behaviors, emotions, perceptions, and dreams that occur during or immediately surrounding sleep. The parasomnias are categorized as nonrapid eye movement (NREM) sleep parasomnias, rapid eye movement (REM) sleep parasomnias, and other parasomnias. This chapter provides an overview to the epidemiology, clinical characteristics, differential diagnoses, diagnostic approach, and treatment of common parasomnias encountered in clinical practice. These common parasomnias include NREM parasomnias, considered to be disorders of arousal from NREM sleep and which include a heterogeneous spectrum of sleep behaviors encountered following arousal from NREM sleep exemplified by the phenotypes of sleep terrors, sleep walking, confusional arousals, sleep-related eating disorder, and sexsomnias; the REM parasomnias, including nightmare disorder, recurrent isolated sleep paralysis, and REM sleep behavior disorder, which is strongly associated with prodromal or overt alpha-synucleinopathy neurodegenerative disorders such as Parkinson disease and dementia with Lewy bodies; and other parasomnias, including a spectrum of “leftovers” that do not map well to NREM or REM sleep specifically such as exploding head syndrome, sleep-related hallucinations, sleep enuresis, and parasomnias ascribed to medical disorders, medication or substance use, or unspecified etiologies. It is important for a psychiatrist to be conversant with the complete range of parasomnias given the importance of effective management of frequent psychiatric and psychological comorbidities, which serve as drivers of the frequency and severity of nocturnal events, and to ensure timely referral for polysomnography or other necessary sleep diagnostics where appropriate.