Antidepressants better than placebo only in severely depressed

Antidepressant medications are more effective than placebo in patients with severe depression, but provide minimal or no benefit to patients with mild or moderate symptoms, according to a new meta-analysis.

The review included six randomized, placebo-controlled trials and 718 patients. The effects of the medications and placebo were compared and patients were stratified according to Hamilton Depression Rating Scale (HDRS) scores. The meta-analysis found that for patients with HDRS scores below 23, the difference in effect between active drugs and placebo was small (less than 0.20 Cohen d effect size). The difference in effect increased as depression severity increased, and became significant at an HDRS score of 25. The study appeared in the Jan. 6 Journal of the American Medical Association.

The researchers were unable to determine whether the difference in effectiveness between severe and less severe cases indicated that medication has greater effect in severely depressed patients or that placebo has less effect in the severely depressed. They concluded, however, that the medications appear to provide substantially more benefit than placebo for severely depressed patients.

For less depressed patients, the analysis reveals little evidence of pharmacological benefit from these medications. Clinicians and patients may be unaware that most proof of the efficacy of these medications has been based on treatment of more severely depressed patients, the researchers noted, and they recommended that efforts be made to clarify general understanding.

The latest issue of the Archives of General Psychiatry also included several studies about depression treatment. A survey of U.S. adults found that about one in five who met the criteria for depression were receiving guideline-recommended treatment and rates of treatment differed by race and ethnicity. A review of claims data revealed that most Medicaid patients who take antipsychotics are not screened appropriately for metabolic risks. Finally, a large study found significant increases in the number of psychotropic drugs prescribed by psychiatrists between 1996 and 2006.