Can panic be induced in deep sleep? Examining the necessity of cognitive processing for panic.

This study examines the relative contribution of biological and psychological processes to the induction of panic attacks by a biochemical challenge agent. Panicogenic doses of caffeine were administered to 8 panic disorder (PD) patients and 11 healthy volunteers during stage 3-4 sleep, when cognitive processing is minimal and the threshold to external stimuli is high. Panic attacks were induced directly from sleep in 3 subjects and subclinical panics in an additional 3. Subjects who experienced full panic attacks spent periods of time ranging from 4 to 52 minutes in stage 2 sleep before awakening in a panic, while those who awakened in subclinical panic awakened almost directly from stage 4 sleep. PD patients experienced significantly more panic symptoms than healthy volunteers. Although limited by a small sample size, this study suggests a combined biological-psychological model of panic induction in which panic disorder patients are more biologically predisposed than healthy controls to panic symptoms but may require cognitive processing for the elaboration of a full panic attack.