DIFFERENCES IN SYMPTOM STRUCTURE BETWEEN PANIC ATTACK AND LIMITED SYMPTOM PANIC ATTACK - A STUDY USING CLUSTER-ANALYSIS

We had investigated the clinical characteristics of panic disorder (PD ) in a Japanese outpatient population comprised of more than 250 patie nts diagnosed as having PD during a 13-year study period and observed that some PD patients had both panic attacks (PA) and limited symptom panic attacks (LPA). In the criteria for PD based on the Diagnostic an d Statistics Manual of Mental Disorders, third edition-revised (DSM-II I-R), episodes involving four or more symptoms are classified as PA, w hile those involving fewer than four symptoms are described as LPA. Th erefore, LPA is identified as part of an episode of PA, since the diff erence between the two episodes is only in the number of symptoms. How ever, some recent research suggests that there is a distinct subgroup of individuals who suffer LPA. Using cluster analysis, we investigated the differences between PA and LPA groups in terms of the structures of several panic symptoms, which included anticipatory anxiety, agorap hobia and 13 clinical symptoms based on the DSM-III-R at the time of p anic attacks, in 247 patients with PD Cluster analysis revealed cluste rs of three and four panic symptoms in the PA group and LPA group, res pectively, and there were also differences in symptom structure betwee n the two groups. These results suggest that there may be a subgroup o f individuals who show LPA among PD patients.