Research Highlights: Only Severely Depressed Affected by Anti-Depressants

Only Severely Depressed Affected by Anti-Depressants

Caroline Melhado

A recent study published in the Journal of American Medical Association found that common anti-depressants only helped the severely depressed, while people with milder forms of depression on the antidepressants exhibited little to no difference compared to those on a placebo regimen.

The meta-analysis included six studies, which included 434 patients given anti-depressant regimen and 284 on a placebo regimen. The patients were rated on the Hamilton depression rating scale, with the lowest score among the trials being 10 and the highest a 39. Three studies used paroxetine, a serotonin reuptake inhibitor, and the remaining used imipramine, a tricyclic antidepressant. The study suggests that other popular, similar anti-depressants, such as Lexipro and Prozac, would show similar results. Studies included in the analysis studied patients older than 18 and did not perform a placebo washout period, normally weeding out people particularly susceptible to a placebo.

The studies all concluded that the presentation of true drug effects was a function of the severity of depression. Patients with a score of 25 or lower (mild to moderate depression) showed no difference between the placebo and Anti-depressant groups. Conversely studies found those with a score of 25 or higher (severe depression) responded to the anti-depressant medication with increasing efficacy as their HDRS number increased.

Reference: JAMA. 2010;303(1):47-53.

Caroline Melhado is the 2009 - 2010 Research Highlights Editor.