Prevalence of panic disorder and other subtypes of anxiety disorder and their background.

Two hundred and forty-four patients with various subtypes of DSM-III anxiety disorder were found among 3,059 outpatients who visited our clinic consecutively for evaluation for five years. They included 53 patients with panic disorder comprising an outstanding number of patients, about a quarter of patients with anxiety disorder and 1.7% of the whole outpatient population, and 78 with generalized anxiety disorder. Differentiation between these two groups was difficult to make besides their specific clinical features whether the patient had panic attacks or chronic generalized anxiety. The patients with anxiety disorder were divided into two major groups--panic-generalized anxiety-simple phobia and social phobia-obsessive compulsive-agoraphobia--in respect to their age of onset of the illness, the duration of episode, separation from their parents, psychosocial stressors and response to pharmacotherapy. Social phobia and obsessive compulsive disorder comprised those patients with similar qualities to each other in terms of their demographic data and their social backgrounds, forming a distinct group apparently different from the panic-generalized anxiety group. They consisted predominantly of young male patients with an earlier onset of the illness, less separation experienced and a longer duration of the episode, while without meaningful psychosocial stressors preceding the present episode. These findings indicate that the prevalence of panic disorder in the Japanese population is as high as previously reported, although its discriminant factors from generalized anxiety disorder are ambiguous except for panic attacks.