The benefits obtained from antidepressants may vary according to the severity of the patient's depression, says a new article appearing in the January 6, 2010 issue of JAMA, and they may only provide significant benefit for those with severe depression.
Jay C. Fournier of the University of Pennsylvania and his colleagues conducted a meta-analysis to estimate the benefit of antidepressant treatment vs. placebo across a wide range of initial symptom severity in patients with depression, combining data from six large-scale, placebo-controlled randomized trials including 718 adult patients.
The authors found that the efficacy of antidepressant treatment varied considerably and was dependent upon how severe the patient's depression was. True drug effects (defined as an advantage of antidepressant treatment over sham treatment with a non-drug placebo) were non-existent to negligible among patients with mild, moderate or even severe depression symptoms. They were, however, large for patients with very severe depression symptoms.
"What makes our findings surprising," say the authors, "is the high level of depression symptom severity that appears to be required for clinically meaningful drug/placebo differences to emerge," especially since the majority of patients receiving antidepressant treatment appear to have depression below these levels.
Efforts should be made, the authors conclude, to clarify to clinicians and patients that whereas antidepressants can have a substantial effect for those with more severe depression, there is little evidence to suggest that they give much benefit for those with less severe depression.