Secondary depression in panic disorder: an indicator of severity with a weak effect on outcome in alprazolam and...

Depressive symptoms are frequent in panic disorder. Among 123 Scandinavian patients participating in a placebo-controlled multicenter study of the efficacy of alprazolam and imipramine treatment in panic disorder, 21% and 23% fulfilled the DSM-III criteria of current and past major depressive episode, respectively, and 17% had dysthymia, even when melancholia and depressive episode with onset prior to the panic symptoms were excluded. According to a subscale of the Hamilton Rating Scale for Depression (HRSD) with higher validity than the full scale, 18% were classified as major depression and 57% as minor depression. A major finding was that patients with affective symptoms had higher scores on many psychopathological measures, including several Symptom Checklist-90 factors. Accordingly, secondary depression was suggested as an indicator of the severity of panic disorder. Depressed and nondepressed patients significantly improved on major outcome measures, but patients with current minor or major depression improved less. Although the sample was too small for detailed analysis of differences in drug efficacy, there was no indication that imipramine was more effective than alprazolam, considering scores on an HRSD subscale.