Predicted versus unpredicted panic attacks: acute versus general distress.

Acute and longer term effects of unpredicted and predicted panic attacks were examined in a sample of patients with panic disorder who self-monitored their panic attacks over a 2-week interval. The study assessed the degree to which experimental observations of the effects of predictability over aversive events are paralleled in the clinical phenomenon of panic. For patients who experienced predicted and unpredicted panics, daily ratings of anxiety and worry about panic increased the day following unpredicted panic attacks and decreased or stabilized the day following predicted panic attacks. These patterns were not replicated in patients who experienced only 1 type of panic; nor were these patterns influenced by the frequency with which panic attacks occurred. Acute distress indexes did not differ during predicted and unpredicted panics, although patients who experienced predicted panic attacks exhibited more pervasive agoraphobic avoidance. The findings are discussed in relation to the safety-signal theory of prediction and alternative conceptualizations.