A Cochrane review included 7 studies. Four of these compared antidepressants and placebo, two compared two antidepressants and one-three armed study compared two antidepressants and a placebo arm. For the acute phase treatment response (6 to 12 weeks), there was no difference between antidepressants and placebo on the symptoms of depression when measured as a continuous outcome (SMD -0.45, 95% CI -1.01 to 0.11; 5 RCTs, n=266) or as a proportion of people who had depression (RR 0.82, 95% CI 0.62 to 1.08, 5 RCTs, n=417). There was no statistically significant difference between selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs) (SMD -0.08, 95% CI -0.34 to 0.18; 3 RCTs, n=237). No trials reported data on the follow-up response (more than 12 weeks). Antidepressants did not cause more dropouts compared with placebo (RR 0.87, 95% CI 0.49 to 1.53, 6 RCTs, n=455), and there was no difference between SSRIs and TCAs either regarding this endpoint (RR 0.83, 95% CI 0.53 to 1.30, 3 RCTs, n=237).
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment, more than 20% loss to follow up), inconsistency (heterogeneity in patients) and indirectness (short follow-up time).