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“. . . by the late 1980s . . . the chemical imbalance theory of depression . . . should have been dead in the water. Yet, it managed to survive long enough to be revitalized by the pharmaceutical industry a few years later in the interests of marketing the new generation of blockbuster drugs: the SSRIs. In the process, the theory was transformed from an unsubstantiated supposition into what was perceived as a scientific truth, and this was what persuaded subsequent generations to flock to their doctors to get pills for depression.”

—Joanna Moncrieff, Chemically Imbalanced, 2025.

While it is debatable as to exactly which of the many war-mongering lies told by politicians has resulted in the most disastrous outcome, when it comes to falsehoods declared by the psychiatry establishment and their Big Pharma partners, it would be difficult to find one that has created more damage than the chemical imbalance theory of depression—harming not only individual patients but society. This is the subject of psychiatrist Joanna Moncrieff’s recently published Chemically Imbalanced: The Making and Unmaking of the Serotonin Myth.

Moncrieff is a consultant psychiatrist for the National Health Services (NHS) in England, Professor of Critical and Social Psychiatry at University College London, and co-chairperson of the Critical Psychiatry Network.

In 2022, Moncrieff was the lead author of a landmark review of research studies that showed that there is no evidence that depression is caused by a serotonin imbalance. This systematic analysis of the research became one of the most widely read and influential papers in recent times (ranked by the online influence tracker Altmetric in the top 5% of all scientific papers ever written). While Moncrieff’s conclusion was no surprise to those in the scientific community familiar with some of these studies, it was a shock to much of the public, which for decades had repeatedly heard the opposite message—that serotonin deficiency caused depression—from establishment psychiatry and antidepressant commercials. This made Moncrieff’s review “newsworthy” for the mainstream media (for example, CBS’s 2022 story “Depression is Not Caused by Low Levels of Serotonin, New Study Suggests”).

The huge reaction to her review made it clear to Moncrieff that the public had an interest in the entire story behind the serotonin myth. Chemically Imbalanced is a hugely important book in which Moncrieff provides a comprehensive account of the origin and a history of the chemical imbalance theory of mental illness; the lack of evidence for a serotonin theory of depression; the primary reason for its persistence despite lack of evidence (an irresistible tool of drug companies for the marketing of antidepressants); the ineffectiveness and adverse effects of antidepressants; andthe bizarre manner in which establishment psychiatry has defended itself and attacked Moncrieff for her truth telling.

While psychiatry has had other major debacles—for example, the inflated results of antidepressant effectiveness reported by the STAR*D study, replete with scientific misconduct—its dishonesty about the serotonin imbalance theory of depression has resulted in something even more insidious: a distorted view of the nature of our humanity that not only has had major negative treatment consequences but harmful cultural and political consequences as well.

Moncrieff and her co-researchers were not the first to bring to light studies showing that depression was

unrelated to a serotonin deficiency, but what they achieved in their 2022 paper was to definitively reject this chemical imbalance theory of depression. In the 1998 book Blaming the Brain, psychologist Elliot Valenstein had provided a handful of studies showing this lack of a relationship between serotonin and depression, concluding, “Furthermore, there is no convincing evidence that depressed people have a serotonin or norepinephrine deficiency.” However, Moncrieff and her co-researchers, by analyzing all relevant studies since this theory was proposed, put the final nails in the serotonin-imbalance coffin.

The relationship between depression and serotonin has long been studied through various means. The most direct method is to measure the breakdown product of serotonin (serotonin’s metabolites) of........

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