A new study published in the Journal of the American Medical Association finds that antidepressants are only useful for patients with severe depression, otherwise a placebo is just as effective as the drugs. For the study, Researchers from the University of Pennsylvania combined data from 6 studies that included 718 patients.
Researchers said they did not expect to find how little effect antidepressant medications had on patients with mild or moderate symptoms.
“What makes our findings surprising is the high level of depression symptom severity that appears to be required for clinically meaningful drug/placebo differences to emerge, particularly given the evidence that the majority of patients receiving [antidepressant medications] in clinical practice present with scores below these levels.”, wrote researchers.
According to researchers, the study results differ from with many other studies that find a benefit of antidepressants over placebo, because entry for study participants are often limit to people with very severe depression, then those results are generalized to patients with moderate to mild symptoms.
Pharmaceutical companies have reacted quickly to challenge the study. Antidepressants are big business. It is estimated that in the U.S. antidepressants account for almost $10 billion in sales annually.