Are antidepressants effective only in severe depression?

According to a study conducted by scientists from the University of Pennsylvania, antidepressant drugs have an exressed clinical effect only in severe forms of depression.

The researchers analyzed data from 6 randomized, placebo-controlled clinical trials conducted by the US Food and Drug Administration  (FDA). In the course of these studies following drugs were used: Paroxetine (SSRIs) or imipramine. The total number of patients was more than 700, the total length of the disease - from 2 to 3 months.
According to the study, in patients with mild to moderate forms of depression, the effect of antidepressants is not clinically significant compared with placebo.
The high degree of efficiency with antidepressants treatment was obtained only with the use of drugs in patients with severe forms of depression.

The study is published in the January issue of the American Medical Association magazine.