Cooper Davis

The Chemical Imbalance Myth: What Jack Goulder Gets Wrong I've read the recent Substack article by Jack Goulder entitled Merchants of Psychiatric Doubt and the subsequent exchanges with Dr Horowitz. First of all, I think it was poor judgment of Goulder to misquote Horowitz and Moncrieff, particularly when that quotation was central to his accusation that they had misrepresented their research. More fundamentally, though I think his dismissal of Horowitz's argument as "semantic somersaults" overlooks an important historical distinction. Contrary to the impression given in the article, the chemical imbalance theory was not simply a marketing narrative seized upon by drug companies. It was actively promoted and legitimised by influential figures within institutional medicine, particularly psychiatry. Until relatively recently, the NHS reproduced versions of this explanation on its websites, and as recently as 2025, Rebecca Brendel, a former president of the American Psychiatric Association, was publicly linking low serotonin with depression in the Washington Post. Psychiatry itself helped establish the credibility of this narrative, and the profession's role in promoting it deserves serious historical scrutiny. This matters because the chemical imbalance theory was not merely an abstract scientific hypothesis. It fundamentally shaped how depression was understood by the public, how SSRIs were presented to patients, and potentially how people made decisions about treatment. Millions of people were given the impression, by psychiatrists, GPs and medical journalism, that SSRIs corrected an underlying chemical deficiency. That is a very different proposition from telling patients that these drugs alter brain chemistry in ways we do not fully understand, that their average benefits over placebo are relatively modest, and that they carry risks. The chemical imbalance narrative also had important implications for long term prescribing. If patients believed they had an underlying serotonin deficiency, it was entirely reasonable for them to conclude that they might need medication indefinitely, just as someone with diabetes might require insulin. Whether and to what extent that belief contributed to long term prescribing deserves investigation, but it is hardly a trivial question. In other words, the theory that depression results from low serotonin played an important role in legitimising the widespread use of SSRIs, including their long term use. We now know that this explanation was not supported by the evidence. It is therefore entirely reasonable to say that research challenging the serotonin hypothesis also calls into question one of the principal historical rationales offered for prescribing these drugs. It is true that this is not the same as claiming that SSRIs have been demonstrated to be ineffective. Whether a drug produces a clinically meaningful benefit is a separate empirical question from whether it corrects the biological abnormality it was purportedly prescribed to treat. The is a substantive difference not a semantic one. It also raises important questions about informed consent. Patients are entitled to accurate explanations of why a treatment is being recommended, not simply evidence that it may produce some benefit. What I find particularly striking about the article is that Goulder devotes considerable attention to the philosophical commitments of psychiatry's critics, while giving comparatively little scrutiny to the professional and institutional commitments that helped sustain the chemical imbalance narrative for decades. If his concern is how prior beliefs and institutional interests shape the interpretation and communication of scientific evidence, surely that scrutiny should apply equally to mainstream psychiatry. One can reasonably argue that the serotonin hypothesis has no direct bearing on the evidence from antidepressant efficacy trials. But it does not follow that discrediting the hypothesis has no bearing on the historical justification for prescribing these medications, or on the decisions patients made after being told they suffered from a chemical imbalance. To characterise that distinction as "semantic" is, I think, to fundamentally miss the point of why setting the record straight about the chemical imbalance story matters so much.