Seven placebo-controlled RCTs (4,111 patients) were included in the review. Five trials (2,615 patients) evaluated quetiapine, two evaluated aripiprazole (749 patients) and one evaluated olanzapine (747 patients). All met at least three of the Jadad criteria.
A statistically significant reduction in MADRS score at eight weeks was observed for quetiapine 600mg/day (WMD -4.64, 95% CI -5.82 to -3.46; four RCTs), quetiapine 300mg/day (WMD -4.76, 95% CI -5.75 to -3.76; five RCTs) and olanzapine (WMD -3.1, 95% CI -4.57 to -1.63; one RCT). There was no statistical heterogeneity for any of these outcomes. The change in MADRS score was not statistically significant for aripiprazole.
Statistically significant increases in somnolence, weight gain, fatigue, sedation, extrapyramidal symptoms and akathisia were observed for all pooled second-generation antipsychotics versus placebo; some of these pooled values incorporated significant statistical heterogeneity. A statistically significant reduction in treatment emergent mania was observed for 600mg quetiapine only.