Nightmare disorder, also known as 'dream anxiety disorder', is a sleep disorder characterized by frequent nightmares. The nightmares, which often portray the individual in a situation that jeopardizes their life or personal safety, usually occur during the REM stages of sleep. Though such nightmares occur within many people, those with nightmare disorder experience them with a greater frequency.Nightmares are associated with a range of psychiatric symptoms, full-blown psychiatric disorders such as post-traumatic stress disorder (PTSD) and sleep disturbances.
While some psychiatric, personality, sleep and biological correlates of nightmares have been described, the vast majority of extant studies are cross-sectional, precluding conclusive determination of causality and etiology. Traumatic events, waking psychological distress, or sleep disturbance may contribute to the onset and maintenance of nightmares.