As Harriet Hall has written (https://www.sciencebasedmedicine.org/?p=353), psychiatry bashing is a popular media sport. There seems to be a bias against treatment of psychiatric disabilities, and a common claim is that antidepressants are no better than placebo. The New York Times illustrated both the perpetuation of the myth that antidepressants are ineffective, and the increasing and disturbing tendency of major media organizations to confuse the wholesale acceptance of medical press releases with medical journalism.
In Popular Drugs May Help Only Severe Depression The New York Times credulously publicized the findings of a recent study that claimed to show that antidepressants are ineffective in treating mild and moderate depression. Yes, that’s what the study showed, but the study itself is so limited, so fraught with problems, and the conclusions are so misleading that the article is a terrible disservice.
Before we consider what the study showed, let’s think about what kind of evidence we’d need to conclude that antidepressants don’t work.
First, although there are different types of antidepressants, the term used colloquially refers to antidepressants of a specific type, SSRI’s or selective serotonin reuptake inhibitors. There are other, older types of antidepressants that are rarely used today because of their unpleasant side effects. Hence any study that claims to show that “antidepressants” are ineffective, must look at SSRIs.
Second, there are literally thousands of studies of SSRIs, and it would be helpful to aggregate the results. Aggregating results can be done in a type of paper known as metaanalysis. Metaanlysis adds the results of multiple similar studies to find trends that might not be apparent in individual small studies. But a metaanlysis is subject to several important limitations that must always be considered. The most important limitation is that the authors of the metaanalysis choose the papers to be included. Bias can be introduced by examining only papers that have a desired outcome; that can be accomplished by restricting the inclusion criteria in arbitrary ways.
Let’s look at the study, Antidepressant Drug Effects and Depression Severity. According to the abstract: