Predictors of response to monoamine oxidase inhibitors: do they exist?

Multiple regression analysis was conducted on potential response predictors in a double-blind study of monoamine oxidase inhibitors (MAOI) and placebo treatment in 130 depressed outpatients. Positive main effects were found for sex (female), lack of prior hospitalization, presence of precipitating events. A negative main effect was found for concurrent physical illness. Treatment x predictor effects were found for distinct quality and non-reactivity. Non-reactivity was associated with positive outcome in the active drug group, but with negative outcome in the placebo group [corrected]. Distinct quality demonstrated a more complex effect, its presence being associated with decreased improvement in the treatment group and greater improvement in the control group. No atypical depressive symptoms predicted MAOI response, and we were unable to characterize a specifically responsive MAOI syndrome.