Monoamine Oxidase Inhibitors in Patients With Chronic Pain

To the Editor.—  Two recent studies have shown that monoamine oxidase (MAO) inhibitors are more effective than controlled treatments in depression that is associated with atypical vegetative symptoms of hyperphagia and weight gain. In one study¹ isocarboxazid was superior to placebo early in treatment, and in another study phenelzine was superior to imipramine and placebo.² Patients with depression and atypical vegetative symptoms have been poorly characterized in previous studies of classification and treatment response. Since they may have a specifically good response to MAO inhibitors, it is obviously important that these patients be identified and better described.Earlier,^3,4 we reported that phenelzine was superior to amitriptyline and placebo in patients with chronic pain and depression. To our knowledge, this was the first report of an MAO inhibitor being more effective than a tricyclic antidepressant. Since analgesic use was minimal in the study, we do not believe that