Characteristics of panic attack subtypes: assessment of spontaneous panic, situational panic, sleep panic, and limited symptom attacks.

We report the analyses of daily journal descriptions of 790 self-defined panic attacks from 59 patients meeting DSM-III criteria for panic disorder or agoraphobia with panic attacks. The DSM-III-R specified symptoms occurred with frequencies ranging from choking (17% of attacks) to palpitations (63% of attacks). The mean weekly panic attack severity correlated significantly with the number of symptoms per attack, but not their weekly frequency. Within a given person, situational and spontaneous panic attacks did not significantly differ over a number of characteristics, including severity, duration, frequency per week, diurnal distribution, and the number of symptoms per attack. Limited symptom attacks were less severe, but were otherwise similar to panic attacks. Also, panic attacks during sleep were less frequent than panic attacks in the awake state, but did not significantly differ on other descriptive characteristics. These data support the validity of the symptoms specified for panic attacks by DSM-III-R. They also suggest that within an individual, panic attacks of various subtypes may be descriptively similar, despite the differing contexts in which they arise. In addition, these data question the diagnostic significance of the limited symptom attack-panic attack distinction.