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Placebos as cognitive enhancers?

A recent study on the efficacy of selective serotonin reuptake inhibitors (SSRIs) – antidepressants like Prozac – has been widely reported in the media. Unfortunately it has not been reported very well. Headlines like ‘Antidepressant drugs don’t work’ (The Independent) are misleading. What the study actually found is that the efficacy of SSRIs varies with the degree of depression; subjects with mild depression experienced no benefit, compared to placebo, and depression had to be severe before the drugs significantly outperformed placebo.

There are several lessons here. The first concerns research ethics. The study here is a meta-analysis. The authors used freedom of information laws to get unpublished data submitted to the FDA for licensing of these drugs, and found that with this data added to the published data, the effect size of SSRIs was much smaller than the drug companies would have you believe. This is one example of how drug company funding both promotes and distorts science; unfavorable results often go unpublished (it is likely that the effect size across all studies is even smaller than Kirsch et al. report, since there are very likely to be unfavorable studies that were not reported to the FDA). Funding distorts science independently of reporting effects, since findings are signficantly more favorable to funders independently of such effects. Given that we must find a way to live with corporate financing of science – without this funding, much less science would be done – it seems reasonable to demand that publishing of all results be required as a condition of FDA approval.

The second lesson concerns the use of SSRIs as ‘lifestyle’ drugs. Ever since Peter Kramer’s well-known book Listening to Prozac, bioethicists have been concerned with using them to become ‘better than well’. This data suggests the concern may have been misplaced: for mild depression (oddly) placebo outperformed Prozac. So here’s question for those, like Carl Elliott, who worry that Prozac might render us inauthentic: is it wrong to use a placebo to become better than well?

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1 Comment on this post

  1. Some provocative — and, apparently, scarcely yet researched — concerns about SSRIs are raised in the latest NY Review of Books:

    “It is well known that these medications can cause emotional blunting and dysfunction in sexual desire, arousal, and performance in upward of three of every four patients. But we are writing now to add that we believe these side effects have even more serious consequences than currently appreciated, due to their impact on several other related neural mechanisms.”

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