Major depression in patients with panic disorder: factors associated with course and recurrence.

The relationship between anxiety and depressive disorders has been the subject of considerable interest and controversy. In this study, the occurrence and course of affective illness was systematically examined in 63 patients meeting DSM-III-R criteria for panic disorder. Forty (63%) of the patients had experienced at least one major depressive episode. Of these, 13 (32.5%) experienced their first depressive episode prior to the onset of panic disorder, 15 (37.5%) experienced their first depressive episode after the onset of panic disorder, and in 12 (30.0%) the onset of the disorders was concurrent. Patients with agoraphobia had comparable rates of depression (68%) to patients without agoraphobia (53%, P = NS), and they had similar temporal patterns of depressive illness. Comorbidity with social phobia was associated with an increased longitudinal likelihood of major depression compared to patients without this comorbid diagnosis (P less than 0.05). Patients with longer duration of illness, early onset depression, melancholic depression, or family histories of anxiety or depression had an increased likelihood of having experienced recurrent depression. These findings are discussed in the context of current theories regarding the development of affective illness in patients with anxiety disorders.