7 Things to Know About Parasomnias

1. NREM sleep arousal disorders. Although not specified in DSM-5, the simplest of the disorders of arousal is confusional, hence disordered, arousal, which is partial awakening with periods of apparent confusion and inappropriate or absent responsiveness to others while in bed. There is typically amnesia for the event and minimal or no recall of dream mentation. This can evolve into spells including intense autonomic activation with vocalization, tachycardia, tachypnea, mydriasis, diaphoresis, and sleep terrors or sleepwalking. ©Ollyy/Shutterstock

2. Substance-/medication-induced sleep disorder. Parasomnias resembling disorders of arousal can be related to the use of many psychotropic drugs, in particular sedative-hypnotics. Sleepwalking and other amnestic complex sleep-related behaviors have been reported among psychiatric patients taking benzodiazepines. Behaviors can be prolonged and include amnestic nocturnal eating, sexual activity, and even sleep driving. ©RinSeiko/Shutterstock

3. Nightmare disorder. Formerly termed “dream anxiety attacks,” nightmare disorder is now recognized as an REM sleep phenomenon, distinct from NREM sleep terrors. As defined in DSM-5, this includes repetitive, extended, extremely dysphoric, and well-recalled dreams that involve threats to survival, security, or physical integrity; episodes usually occur during the second half of the sleep period. Typically, the individual becomes rapidly alert and oriented. Emotional manifestations of fear, anger, and sadness may predominate. ©LukiyanovaNataliaFrenta/Shutterstock

4. REM sleep behavior disorder. RBD patients-most frequently older men with who experience a prolonged, chronic course-typically dream of themselves as defenders, rarely as aggressors. Violent dream enactment can result in injury to the patient and/or bed partner whose presence is often incorporated into the dream content. RBD spells are likely to occur during the latter part of the night, when REM sleep tends to be more prolonged and intense. For about 25% of patients, there is a prodromal period with increased action-packed dream content along with vocalization and limb jerking that can progress over several years. As RBD becomes established, there is a tendency for abrupt, often violent movement concordant with recalled dream content. ©Makieni/Shutterstock

5. Recurrent isolated sleep paralysis. Sleep paralysis is essentially the atonia of REM sleep that has become dissociated and occurs at times other than the typical periods of REM sleep during the night. It can either intrude at sleep onset or persist into awakening at sleep offset, and it is often experienced as discomforting or frightening. It is classically found in association with narcolepsy, but not exclusively. ©IrynaGyrych/Shutterstock

6. Sleep-related events not specified in DSM-5. Clinical features of nocturnal spells can resemble panic disorder, but diagnostic caution must be emphasized. Other disorders that can masquerade as nocturnal panic, such as sleepwalking/sleep terrors, RBD, seizures, gastroesophageal reflux, obstructive sleep apnea, bruxism, nocturnal asthma, and nocturnal cardiac arrhythmias. Sleep disturbances have figured prominently in descriptions of dissociative identity disorder, dissociative amnesia, PTSD, and other disorders. ©Namning/Shutterstock

7. Other rare but relevant disorders with sleep-related manifestations. Sleep-related epilepsy should be considered for any sleep-related behavior that is recurrent, inappropriate and, most importantly, stereotyped. Exploding head syndrome is a sudden sensation of a loud noise or a violent, though painless “explosion” in the head occurring as the affected person is falling asleep or waking during the night. It is a rare, benign but frightening event during the transition between wake and sleep. Sleep-related hallucinations can be related to narcolepsy, ß-adrenergic receptor blocking medications, dementia with Lewy bodies, visual loss (Charles Bonnet hallucinations), and other brain pathology (peduncular hallucinosis). ©Namning/Shutterstock

_{This article was posted on August 17, 2017, and has since been updated.}