Are two actions better than one? A meta-regresion analysis of the predictive value of pharmacological activity on the relative effecacy of antidepressant drugs

BACKGROUND: There is uncertainty about the contribution of specific pharmacological properties to the efficacy of antidepressants. AIMS: To assess whether specific pharmacological characteristics of alternative antidepressants resulted in altered efficacy compared to that of selective serotonin reuptake inhibitors in the treatment of major depression. METHOD: Meta-regression analysis of randomised trials that compare treatment with a selective serotonin reuptake inhibitor and an alternative antidepressant. RESULTS: One-hundred-and-five randomised trials were included. None of the factors identified a priori predicted a statistically significant improvement in outcome across the trials. CONCLUSIONS: This analysis does not provide evidence that antidepressants acting at more than one pharmacological site differ in efficacy from drugs selective for serotonin reuptake in the treatment of major depression.