Depression is frequently found in patients with panic disorder. It is known that patients suffering from panic disorder and depression have more severe symptoms of anxiety and avoidance and respond less well to treatment with antidepressants. The General Behaviour Inventory, an instrument that identifies subjects with subsyndromal and syndromal recurrent mood disorders was completed by 108 patients in a panic disorder program. Thirty-four percent (n = 37) were classified as suffering from a mood disorder. Of the mood disordered patients, 25 of 37 (68%) (23% of the total) were classified as suffering from bipolar or cyclothymic mood disorder.