A leading psychiatrist has challenged the widely accepted explanation that depression is caused by low levels of “happy hormones” in the brain, calling the so-called “chemical imbalance” theory a myth. Professor Joanna Moncrieff of University College London argued that antidepressants do not work by correcting a specific brain fault but may instead ease suffering by dampening emotional experience, including feelings of happiness, excitement, love, and sexual desire.
Her comments, featured in an upcoming Care Visions Talks podcast and in the newly released paperback edition of her book, *Chemically Imbalanced*, come amid rising antidepressant prescriptions in England. Currently, more than nine million adults—roughly one in five—are prescribed these medications.
Professor Moncrieff, who led an extensive review examining the link between serotonin levels and depression, said the evidence does not support the idea that low serotonin causes depression. “We found that none of those areas provided convincing or consistent evidence of there being a link between low serotonin and depression,” she stated.
She urged for a “revolution in mental health treatment” that shifts attention away from medication as the primary response. Instead, she emphasized addressing the underlying causes of distress by expanding access to therapies, physical exercise, and social support. According to Moncrieff, depression typically arises as a reaction to life circumstances, though genetics and biology may affect individual vulnerability. She expressed concern over what she described as the “medicalising” of emotional and life difficulties and questioned the widespread use of psychiatric drugs as a solution.
The chemical imbalance theory originated in the 1960s following the discovery that antidepressants alter neural compounds, but Professor Moncrieff maintains that subsequent research has not definitively linked depression to serotonin deficiency. However, her conclusions have faced criticism from some experts who argue that the serotonin system’s involvement may be more complex and that the review’s methodology was flawed. Additionally, many patients report significant benefits from antidepressant treatment.
Current NHS guidelines recommend antidepressants mainly for moderately severe or severe depression and advise that patients be fully informed about the drugs’ side effects and other treatment options. The use of antidepressants is generally discouraged for individuals under 18 unless combined with other therapies, and patients are cautioned against abrupt discontinuation without medical advice.