Expectations about arousal and nocturnal panic.

Expectations about arousal were examined in relation to nocturnal panic (NP). Eighteen panic disorder patients suffering from NP attacks and 18 control individuals were assigned randomly to conditions in which they were informed that audio feedback signals reflected heightened arousal that was either (a) expected and harmless or (b) unexpected. Participants relaxed and slept for 45 to 60 min, followed by presentation of periodic audio feedback signals. Physiological recording was continuous while subjective measures were collected at completion of the signals phase. NP patients in the unexpected--no reassurance condition were significantly more anxious and symptomatic than their counterparts in the expected reassurance condition, whereas control individuals did not differ across the 2 conditions. Physiological and behavioral data were less consistent than subjective measures. The results are interpreted as supportive of a cognitive-behavioral model of NP.