Treatments for depression are difficult to study.  First, depression is a condition that can improve without treatment.  So any treatment must be compared to placebo to see if the treatment is responsible for the improvement or if the depression improved on its own.  Also, depression can not be measured objectively.  There is no objective test like an X ray or a blood test that can diagnose depression.  (At least not yet.  As our understanding of brain function improves, such a test is certainly...