Practical Ethics

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 The authors used freedom of information laws to get unpublished data submitted to the FDA for licensing of these drugs, and found that with this data added to the published data, the effect size of SSRIs was much smaller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 This is one example of how drug company funding both promotes and distorts science; unfavorable results often go unpublished (it is likely that the effect size across all studies is even smaller than Kirsch et al.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?

The Daily Mail reports on a helmet that supposedly ‘could reverse the symptoms of Alzheimer's disease within weeks of being used’. The helmet uses near infrared light, which can penetrate the skull of patients. According to the Mail:

Its creators believe it could reverse the symptoms of dementia - such as memory loss and anxiety -          after only four weeks.

 Sounds too good to be true, doesn’t it? It probably is.

The research hypothesis – that near infrared light would reverse cognitive decline – was apparently suggested by the use of near infrared to treat cold sores (the scientists who have developed the dementia helmet have also marketed a device to treat cold sores, and hope to market a dementia helmet in due course). Near infrared may be effective in treating cold sores because it accelerates healing. It is a huge leap, though, from wound healing to dementia. For one thing, neural cells do not regenerate at anything like the same rate as other cells: stimulating them to regenerate faster would have a small effect.

The scientists do have some evidence for their claims: a single study of memory deficits in mice. They used mice which exhibit significant memory impairments; their group of mice demonstrated a significant reduction in maze navigation errors after exposure to near infrared mice. However, there is no good reason to think this mouse study (which used only ten treated mice, and which therefore has low statistical power) is actually relevant: the deficits these mice exhibit are not a model for Alzheimer’s.

 What this story really demonstrates are the costs and the benefits of encouraging scientists to commercialize their research. On the one hand, a line of research is being pursued that is speculative, but which may prove fruitful. It is extremely unlikely that it will result in a cure for Alzheimer’s, as the scientists suggest, but it may play a role in treatment, and may slow cognitive decline. Financial incentives are working in just the way that we might hope in encouraging this research. But the premature publicity and the hype surrounding the dementia helmet represents a cost of encouraging commercialization. In their attempt to generate publicity and therefore market share for their device, the scientists are raising hopes that they will almost certainly fail to satisfy.

Race, IQ and James Watson

A couple of months ago, James Watson – who, together with Francis Crick, was awarded the Nobel Prize for deciphering the double helix structure of DNA – claimed that black people are less intelligent that white  He invoked the authority of science to make his claim. Of course, if the claim had simply been that on average (say) African-Americans had lower scores on IQ tests than White Americans (and that this difference was reflected in educational achievement and other socioeconomic indicators), Watson would simply have been citing facts. The controversial part of Watson’s claim was that the difference was rooted in the genes of blacks and whites and therefore fixed. The first part of the claim is (probably) false – the genetic differences between blacks and white are largely skin deep. But even were it true it would be irrelevant to the real question. Watson calls himself ‘gloomy about the prospect of Africa’, because he thinks that ‘genetic’ means ‘fixed’. But ‘genetic’ does not mean ‘fixed’; the fact that the differences between two individuals are explained by differences in their genes has no implications whatsoever about how hard or easy it is to eliminate the difference. Differences rooted in environmental factors (to the –limited – extent to which it even makes sense to separate environmental factors from genetic) may be easier to eliminate than those rooted in the genes, or they may be harder. Genes work like sets of switches, under the control of other genes and environmental factors. These sets can be configured differently to produce very different results; changing a few triggers thereby produces very different products from much the same genes. In any case, the evidence strongly suggests that this particular IQ deficit is remediable.