Secondary depression in panic disorder and agoraphobia. I. Frequency, severity, and response to treatment

Depressive symptomatology in 481 subjects with panic disorder and phobic avoidance was studied as part of an investigation of the efficacy of alprazolam in panic disorder. Subjects who had a major depressive episode (MDE) before the onset of their panic disorder were not included in the trial. With this exclusion criterion, 31% of subjects had a secondary MDE occurring after the onset of the panic disorder. The occurrence of secondary MDE was related to the length of time subjects were ill with panic disorder. Compared with the subjects without depression, those subjects with current MDE had higher scores on measures of anxiety and depression but not on the number of panic attacks per week. The presence of depression and the degree of phobic avoidance contributed independently to measures of the severity of the panic illness. Alprazolam was effective in reducing panic and depressive symptomatology in both depressed and nondepressed subjects with panic disorder. The presence of an MDE was not predictive of the outcome of treatment for the panic and phobic symptoms. Subjects with or without depression responded similarly to alprazolam.