The influence of panic attacks on response to phenelzine and amitriptyline in depressed outpatients.

A total of 169 depressed outpatients completed a 6-week double-blind study designed to compare the relative efficacy of a tricyclic antidepressant (amitriptyline) with a monoamine oxidase inhibitor (phenelzine). Various "target" symptoms reported to predict preferential response to monoamine oxidase inhibitors were assessed. The major finding within the whole patient sample, based on results from serial self-report and interviewer-rated scales, was that phenelzine-treated patients showed greater improvements in anxiety symptoms than did patients treated with amitriptyline. Because of the heterogeneity of the sample, patients were classified into homogeneous subgroups of clinical interest. Data analyses of these subgroups detected important drug treatment differences not discernible by analysis of data from the overall sample. Panic attacks and corresponding anxiety symptoms were reported by about one third of the patients, more often by patients with major depression than with minor depression. Patients who reported "spells of terror or panic" responded preferentially to phenelzine on several measures, particularly on items measuring anxiety. Results suggest that phenelzine may be a preferred drug for treating depressed patients with panic attacks.