Antidepressants for major depressive disorder in patients with a co-morbid axis-III disorder: a meta-analysis of patient characteristics and placebo response rates in randomized controlled trials.

The objective of this study is to assess whether the antidepressants are effective in treating major depressive disorder (MDD) in patients with a co-morbid axis-III disorder, and to compare the relative efficacy (vs. placebo) of antidepressants between these patients and those enrolled in general MDD trials. Medline/Pubmed publication databases were searched. We selected for randomized, double-blind, placebo-controlled trials of antidepressants for MDD, whether conducted in a general population, or in populations with an axis-III disorder. Antidepressants were more effective than placebo in patients with axis-III disorders overall [risk ratio for response (RR)=1.42, P<0.0001], as well as specifically for post-stroke (RR=1.43, P=0.04), human-immunodeficiency virus positive or acquired immunodeficiency syndrome (RR=1.66, P=0.005), but not cancer patients (RR=1.26, P=0.19). There was a trend for higher placebo response rates in studies, which did (41.2%) versus those which did not (37.7%) select for axis-III disorders (P=0.06), and significantly higher antidepressant response rates in studies which did (57.4%) versus those which did not (53.5%) select for axis-III disorders (P=0.01). Antidepressants are effective for MDD in patients who present with co-morbid axis-III disorders and as effective (vs. placebo) in this population as they are in the general MDD population. Higher general response rates observed in the co-morbid MDD population are intriguing, and require replication.