A Cochrane review included 7 studies with a total of 482 subjects. For severity of depression, results favour antidepressants (“very much" or "much" improved on the Clinical Global Impression Scale: RR 1.92, 95% CI 1.26 to 2.94; 2 trials, n=183), while another study, utilising the Hamilton Depression Rating Scale, did not find a statistically significant difference (RR 0.96, 95% CI 0.54 to 1.71; n=95). Comparing antidepressant with placebo, no statistically significant results for dropouts were found, however results favour placebo in studies with low risk of bias (RR 1.40, 95% Cl 1.00 to 1.96; 4 trials, n=325). Adverse events were more common with antidepressant compared to placebo (RR 2.90, 95% Cl 1.23 to 6.86; 4 trials, n=311). For drug use, no statistically significant difference was seen (3 studies with different outcome measures, n=211). Severity of depression was more improved with tricyclics than with placebo (RR 1.92, 95% Cl 1.26 to 2.94; 2 trials, n=183), but not in comparison of SSRIs vs placebo in one small study.
Comment: The quality of evidence is downgraded by study quality (inadequate or unclear allocation concealment and incomplete outcome data addressed in half of the trials), by inconsistency (heterogeneity in interventions and outcomes), and by imprecise results (limited study size for each comparison).