Is the antidepressive effect of second-generation antidepressants a myth?

Abstract

Two recent meta-analyses on second-generation antidepressants versus placebo in mild to moderate forms of major depression, based on data on all randomized clinical trials using the Hamilton Depression Scale (HAMD) submitted to FDA, have shown an effect size of 0.30 in favour of antidepressants in the acute therapy of major depression. The clinical significance of an effect size at this level was found to be so poor that these meta-analyses have subscribed to the myth of an exclusively placebo-like effect of second-generation antidepressants. A re-allocation of HAMD items focusing on those items measuring severity of clinical depression, the HAMD6, has identified effect sizes of 0.40 for second-generation antidepressants in placebo-controlled trials for which even a doseresponse relationship can be demonstrated. In the relapse-prevention phase during continuation therapy of patients with major depression, the advantage of second-generation antidepressants over placebo was as significant as in the acute therapy phase. To explore a myth is not to deny the facts but rather to re-allocate them. © Copyright Cambridge University Press 2009.