nightmare

A nightmare is a distressing dream that typically induces strong emotions such as fear, horror, or sadness. Nightmares usually occur during rapid eye movement (REM) sleep, often in the latter part of the night, and the dream content is vivid and memorable upon waking. Unlike sleep terrors, which happen during non-REM sleep and may leave the sleeper confused, nightmares are usually remembered and can be recalled in detail.

Nightmares can be triggered by stress, anxiety, trauma, or major life changes. They are more common after sleep disruption, insufficient sleep, or jet lag. Substances such as alcohol or certain medications, including some antidepressants, can contribute. In children, nightmares are relatively common and may reflect daytime fears or exposure to frightening media; in adults, recurrent nightmares may indicate an underlying condition such as PTSD, depression, or an anxiety disorder.

Most people experience occasional nightmares without clinical concern. However, when nightmares are frequent (for example, occurring several times a week) and cause significant distress or daytime impairment, they may be diagnosed as nightmare disorder. Clinicians may assess sleep quality, medical history, and mental health, and screen for trauma or stress-related disorders.

Treatment focuses on improving sleep hygiene and addressing underlying causes. Imagery rehearsal therapy (IRT), a cognitive-behavioral technique, has shown evidence for reducing nightmare frequency and distress. For nightmares linked to PTSD or other conditions, trauma-focused psychotherapy or medical management may be indicated. Some pharmacologic options have been explored, but evidence varies and treatment is individualized.

The term nightmare derives from Old English mare, a mythological demon believed to sit on sleepers' chests and cause bad dreams. In many cultures, nightmares are interpreted through symbolic or supernatural frameworks, while modern psychology treats them as a phenomenon arising from emotional regulation, memory processing, and sleep physiology.