Nocturnal panic.

The phenomenon of nocturnal panic was examined by comparing individuals with panic disorder who reported the experience of nocturnal panic (N = 37) with those who did not (N = 56). Variables that were assessed included frequency and intensity of daytime panic attacks, generalized anxiety, and responses to a standardized physiological assessment. In addition, the most recent nocturnal panic was rated on measures of intensity, duration, and circumstances. Nocturnal panic occurred in individuals who were equally avoidant and distressed as individuals who did not experience nocturnal panic. However, nocturnal panickers experienced daytime panics and general somatic sensations more frequently than other panickers. The similarity of nocturnal panic to sleep apnea, dream-induced anxiety attacks, and night terrors is discussed. The nature of nocturnal panic is described within the context of an explanatory model that combines behavioral and physical factors.