15/07/2025
A landmark review finds no scientific evidence that depression is caused by a chemical imbalance.
A major umbrella review led by researchers at University College London has found no convincing evidence that depression is caused by low serotonin levels or reduced serotonin activity. Published in Molecular Psychiatry, the study analyzed decades of research across several major fields and concluded that the long-standing “chemical imbalance” theory lacks scientific support. This challenges the core rationale behind the widespread use of antidepressants like SSRIs, which are believed to work by correcting low serotonin. The review suggests that the popularity of this theory may have contributed to the massive increase in antidepressant prescriptions despite the absence of biological proof.
The findings also raise concerns about how this serotonin theory may shape public perception and treatment decisions.
With up to 90% of people believing depression stems from a chemical imbalance, researchers warn that this misconception can discourage recovery optimism and reliance on non-drug treatments.
Moreover, some evidence points to antidepressants possibly lowering serotonin levels over time, highlighting a need for transparency and new approaches to mental health care.
The authors advocate for a shift in focus toward addressing life stressors, trauma, and social factors through therapy and lifestyle interventions rather than pharmacological solutions alone.
Source: Moncrieff, J., Cooper, R. E., Stockmann, T., Amendola, S., Hengartner, M. P., & Horowitz, M. A. (2022). The serotonin theory of depression: A systematic umbrella review of the evidence. Molecular Psychiatry
