Nightmares: definition, epidemiology and classification

The term 'parasomnias' encompasses a cluster of sleep disorders marked by abnormal, unpleasant motor, verbal, or behavioral events that transpire during sleep or the transition from wakefulness to sleep. In a study conducted by Italian researchers, nightmares are described as prolonged, highly distressing dreams typically involving efforts to evade threats to survival, security, or physical well-being. Nightmares predominantly occur during REM (rapid eye movement) sleep and manifest with symptoms of physical arousal, such as sweating and shortness of breath. The primary emotional response is fear, although instances of anger, shame, and sadness may also manifest. The prevalence of nightmares varies with age, ranging approximately from 10% to 50% in children under 15 years old, 66% in adults, with a higher frequency in women than in men. It is crucial to note that nightmares can be categorized into posttraumatic and idiopathic types. Emphasis should be placed on distinguishing between nightmares and bad dreams, as they represent distinct phenomena with differing themes.