Tuesday, February 26, 2008

Snake oil

Anti-depressants are some of the biggest-selling pharmaceuticals in the world, taken by over 40 million people. But there's a problem: according to a major study published today, they don't actually work:

In the study, researchers conducted a meta-analysis of all 47 clinical trials, published and unpublished, submitted to the Food and Drug Administration in the US, made in support of licensing applications for six of the best known antidepressant drugs, including Prozac, Seroxat – which is made by GlaxoSmithKline – and Efexor made by Wyeth. The results showed the drugs were effective only in a very small group of the most extremely depressed.


Professor Irving Kirsch of the University of Hull, who led the study published in the online journal Public Library of Science (PLoS) Medicine , said the data submitted to the FDA would also have been submitted to the licensing authorities in Britain and Europe. It showed the drugs produced a "very small" improvement compared with placebo of two points on the 51-point Hamilton depression scale.

That was sufficient to grant the drugs a licence but did not meet the minimum three-point difference required by the National Institute for Clinical Excellence (Nice) to establish "clinical" significance. Yet Nice approved the drugs for use on the NHS in the UK because it only had access to the published trials, which showed a larger effect.

According to the Guardian's version, placebo produced exactly the same gain in all but the most depressed patients. Meaning that the drugs effectively did nothing for most people. There's a name for this: snake oil. And by not requiring pharmaceutical companies to hand over all their data when applying for a licence, our current pharmaceutical licencing system permits and encourages it.