Investigates the prevalence of panic disorder as well as the pattern of association between panic disorder and other diagnostic categories. The study also explores clinical and demographic aspects including sex, age, precipitating factors, and symptom severity and duration. 150 18-50 yr olds with panic disorder in a private psychiatric clinic were asked to complete the Panic Attack Questionnaire. The results showed that the prevalence of panic disorder was 7.4% among the whole patient population and 14.5% among the patients with neurosis, with a higher prevalence among females. The majority of panic attacks were precipitated by either psychosocial stress or somatic stimuli. The presence of other clinical entities in conjunction with panic disorder resulted in 6 subgroups: panic disorder alone or panic disorder with agoraphobia, social phobia, depression, simple phobia, or generalized anxiety. A comparison between the 6 sub-groups and the severity of symptoms failed to find differences among diagnostic categories. However, the correlation between severity of symptoms and precipitating factors was weakly supported.