Differences between those who panic by day and those who also panic by night.

This study examined the characteristics, correlates, background demographic, and personality variables associated with panic among those who panic exclusively from a waking state and those who also panic out of sleep. Participants were recruited through advertising in print media and through anxiety/panic support groups. Some group differences in the characteristics of panic and the associations between panic and other variables were found. Specifically, levels of anxiety sensitivity were higher, panic duration was longer, and panic was less strongly related to catastrophic cognitions for the group that experienced nocturnal panic. These differences are cautiously interpreted as not supporting a "strong" cognitive theory of panic initiation.