Monoamine Oxidase Inhibitors in the Treatment of Atypical Depression

In a 6-week, double-blind study outpatients diagnosed as suffering from atypical depression were treated with either isocarboxazid or placebo. Selection criteria were purposely broad so as to capture the entire range of patients so diagnosed. Patients were then subclassified along several symptomatic, syndromal, phenomenological, and diagnostic categories in order to identify clinical characteristics specifically responsive to isocarboxazid. Although isocarboxazid was clearly superior to placebo for the overall group of atypical depressives, the authors were by and large unable to identify subgroups specifically responsive to the monoamine oxidase inhibitor. A few factors correlated with better response to both isocarboxazid and placebo: no family history of alcoholism or sociopathy, lack of self-pity, and not meeting Research Diagnostic Criteria for major depressive disorder. The single item that was associated with a statistically significant advantage of isocarboxazid over placebo was loss of anticipatory pleasure. Clinical implications and suggestions for further research are discussed.