According to the Mayo Clinic, about 13% of Americans—more than 1 in 10—take an antidepressant. Of women between the ages of 50 and 64, nearly 1 in 4 take an antidepressant. Second only to antibiotics, antidepressants are the most commonly prescribed class of medication.
A 2008 study led by Dr. Irving Kirsch of Harvard Medical School started a big ruckus in the mental health world. He and his colleagues re-analyzed 35 different antidepressant drug trials submitted to the FDA for the licensing of Prozac, Effexor, Serzone, and Paxil. He used the Freedom of Information Act to get access not only to the studies that showed the drugs worked, but also to the studies that didn’t show an effect, which were, unfortunately, most of them.
For individuals with mild-to-moderate depression, they found that treatment with an antidepressant was almost no different from placebo.
— source scientificamerican.com