Another couple of months has passed since Jerry Coyne, Professor of Ecology and Evolution at the University of Chicago, made his latest claims about psychiatry and psychiatric drugs. I have dissected many of his unreasonable claims about psychiatry on two occasions previously, in Why Jerry Coyne is Wrong about Medical Psychiatry and in the follow-up post Why Jerry Coyne is Still Wrong about Antidepressants. Since I feared that Prof. Coyne had started to slide down that dangerous path into denialism and pseudoskepticism, I decided to send him an email with a few critical questions against his stance to see what he thinks about them. Could it be that he has changed his mind, or has he become frozen in his views?
The email is too long to cite in its entirely (used a lot of references and such, which can be found in the two posts linked above), so I will just summarize my 6 questions. I identified additional problems besides these six, but I feel that these are the main questions I would like to see what Prof. Coyne thinks about at this time.
1. Why does Prof. Coyne describe the mainstream explanatory model for depression as “chemical imbalance”, when most descriptions in elementary level psychology textbooks emphasize a large number of interacting biological, psychological and environmental factors that are each important in their own right?
2. Why does Prof. Coyne think that the fact that the genetics of mental illness is rife with uncertainties undermine the notion that many mental illnesses have genetic predispositions when studies on identical twins and adoption studies show that the heritability is often moderate? Surely, there is a different between knowing that a genetic predisposition exists and knowing the exact mechanism on a molecular level? To take an analogy: even though we may not have all the details of how common descent happened (is this taxon more related to that taxon than this other taxon?), we can be pretty sure of common descent.
3. Why does Prof. Coyne appeal to studies such as Kirsch et. al. (2008) to argue that antidepressants work no better than placebo, when the study actually found that antidepressants outperformed placebo, closely replicating the findings of earlier studies? The reason Kirsch drew the conclusion was due to using an arbitrary cut-off value for clinical significance (0.5) from National Institutes for Clinical Excellence that NICE no longer uses. That is like saying that just because a glass is 1/3 full (the effect size found by Kirsch was 0.32) is not 1/2 (i.e the previous standard for clinical significance set by the NICE), it must be empty (i.e. antidepressants do no better than placebo). If you still think Kirsch conclusion was reasonable, why would you not have to logically reject psychotherapy as well, as it has a lower effect size (0.22) than antidepressants?
4. If Prof. Coyne think that antidepressants outperform placebo because of their supposedly severe side effects, leading the patient to conclude that he or she is on the pharmacological active treatment leading in turn to an increased placebo effect for the experimental group, then should that not mean that newer antidepressants should be less effective in clinical trials than the older ones because the newer ones have less side effects? If so, how does Prof. Coyne explain that, in general, newer antidepressants are more effective (or at the very least, as effective) than older ones?
5. If Prof. Coyne think that antidepressants outperform placebo because of their supposedly severe side effects (per the reasoning outlined in question 5), then why do placebo groups treated with pharmacologically inactive placebo show a similar level of side effects as the experimental group, presumably due to expectations and the nocebo effect, in many different contexts?
6. Why does Prof. Coyne think that the side effects of psychotherapy “are nil”, when there exists well-documented side effects in the literature such as intense anxiety during exposure trials, Bergin’s deterioration effect, negative effects from critical incident stress debriefing, deaths resulting from rebirthing techniques in oppositional children and false memory syndrome from recovered-memory therapy?
It was a quite long email, especially with all of the sources, so there is no guarantee that Prof. Coyne feels that he has the time and interest to reply to it, but hopefully he will, and also give me permission to post and discuss his reply in future blog post. I am very interested in knowing what Prof. Coyne’s current positions on these issues are.
It is often hard to admit that one is mistaken in an area, but whatever one feels that one loses in prestige, one gains back many times over in intellectual integrity.