The benefit-to-harm ratio of antidepressants

A Lancet Psychiatry article attacks Peter Gøtzsche (who I have mentioned in a previous post) for saying that antidepressants do more harm than good. Although his Guardian article has this headline, in fact what he wrote was "the way we currently use psychiatric drugs is causing more harm than good" [my emphasis]. He doesn't seem to be advocating not using antidepressants at all, but "much less, for shorter periods of time, and always with a plan for tapering off, to prevent people from being medicated for the rest of their lives".

As I commented in my previous post about Gøtzsche, the problem is that attacking him in this way deflects from the validity of what he is saying. I wish mainstream psychiatry would engage more with me. I do know it is important to avoid overstatement (see previous post). The Lancet Psychiatry article emphasises the effect size found in antidepressant trials. What it doesn't discuss is whether this finding could be explained by placebo amplification due to unblinding in clinical trials (eg. see previous post). Nor does it discuss the bias in the literature introduced through selective publication. These days this is because data submitted by the drug companies to the regulatory authorities is not always examined completely. Previously, with older trials, this was because of what was called the 'file drawer problem' (see further information) in that negative trials did not always get published. This may well have affected the amitriptyline data that the Lancet Psychiatry article cites.

As I said in a comment on a previous post, it's important not to get too hung up by the size of effect in clinical trials. Maybe I'm too sceptical, but the finding that non-psychiatric drugs have similar effect sizes in clinical trials does not imply that psychiatric drugs are effective, but that medical as well as psychiatric clinical trials are subject to the same biases of unblinding (see previous post).

The authors of the article speculate about the reasons for doctors questioning the effectiveness of antidepressants, suggesting it is the anti-psychological bias of doctors that makes them want to believe that there can't be a physical treatment that could possibly be effective for mental illness. So, they try to turn the tables on critics by suggesting it's the critics not them that are stigmatising mental illness. They feel insulted by the critique but it is important to be open to argument and not prejudiced.