Selective Publication of Antidepressant Trials and its Influence on Apparent Efficacy

In paper citation (Turner, et al., 2008).

In groundbreaking work, Turner and his colleagues invoked the freedom of information act to "check up" on the efficacy of antidepressants. Basically, the majority of studies with negative or questionable results about the efficacy of an antidepressant versus a placebo never get published and therefore do not have a chance to influence people's mentality about the efficacy of antidepressant drugs.

Basically, among the published literature, 94% of antidepressant trials conducted are positive. However, among the FDA registered clinical trials of antidepressants, only 51% of antidepressant trials are positive. This gives us great pause for consideration as pharmaceuticals make billions of dollars a year on these drugs.

I personally would trust the FDA effect sizes now that they are out. The effect size compares the difference in means between the control and the placebo group at the end of the treatment period divided by the pooled standard deviation.

The overall effect size was .31 for the modern antidepressants.