Current Perspectives on Nonrapid Eye Movement Parasomnias

Non-REM (NREM) parasomnias comprise abnormal sleep-related behaviors, autonomic nervous system function, and emotional experiences that typically arise out of deep NREM sleep. Categorized broadly as disorders of arousal (DoA), confusional arousals (CoA), sleepwalking (SW), and sleep terrors (ST) share common pathophysiological mechanisms and contributing factors. Sexsomnia is classified as a variant of CoA and SW, while sleep-related eating disorder is classified as a separate NREM parasomnia. These parasomnias emerge due to incomplete dissociation of wakefulness from NREM sleep, resulting in partial arousal characterized by decreased consciousness during motor and emotional manifestations. The behaviors emerge as a result of the interplay of various predisposing and priming factors with the additional layer of precipitating conditions. Cyclic alternating patterns and abnormal slow wave synchronization increase susceptibility to developing these behaviors in the background of genetic predisposition. We will discuss current diagnostic criteria, differential diagnoses, implications, and management of these parasomnias. Recent scientific developments in this area will be discussed, especially in reference to etiopathogenesis and treatment strategies of lesser-studied subtypes such as sexsomnia. The mainstay of treatment comprises alleviating the contributing factors and treating any comorbid sleep disorders that may curtail sleep duration and also increase abnormal arousal. Behavioral interventions can be beneficial, although sometimes less established pharmacotherapy is also utilized.