Rethinking Depression: The Myth of the Serotonin Deficiency

We've been told for decades a straight-up

lie: depression is caused by a "chemical imbalance" in the brain—a low level of serotonin. That idea has justified the mass dispensing of antidepressants like SSRIs (Selective Serotonin Reuptake Inhibitors) to millions. It's memorable, comforting, and has no basis in fact.

The Reality: There Is No Consistent Evidence That Low Serotonin Causes Depression

In 2022, a trailblazing systematic umbrella review in Molecular Psychiatry by Joanna Moncrieff and colleagues made waves in the world of psychiatry. The decades of research were reviewed, and there was one certain conclusion: There is no strong evidence that depression is associated with, or caused by, low serotonin levels or activity. (Moncrieff et al., 2022)

Let that sink in. The very foundation of the antidepressant industry's advertising—low serotonin = depression—is an illusion.

What the Research Tells Us Instead:

• Depressed people are not necessarily lower in serotonin than non-depressed people.

• Genetic studies find no definitive link between serotonin genes and depression.

• Experimentally lowering serotonin in people does not always induce depression.

• Antidepressants don't fix a shortage—rather, they alter brain chemistry, but not in a way that shows there is an existing imbalance.

Why the Serotonin Theory Caught On

The myth of serotonin burst in the 1990s, as Prozac and other SSRIs became available on the market. Pills were marketed by drug companies as mending a broken brain, just like insulin for diabetics. It was a successful advertising campaign—simple, stigma-reducing, and profitable. Doctors and the public were convinced by it, although many scientists had already recognized that the evidence was unconvincing.

The Real Story Is More Complex

Depression is not an illusion. Depression can be devastating. However, it's not the product of a single neurotransmitter.

Actually, it's shaped by:

• Life experiences (trauma, loss, stress, poverty)

• Social conditions (social isolation, inequality)

• Psychological processes (negative thinking, hopelessness)

• Biology (yes, the brain is included in the equation—but not in a reductionist "serotonin deficiency" way)

What This Means for You

If antidepressants are good for you, okay. But you weren't "short on serotonin." These drugs have effects—sometimes good, sometimes bad—but they're not correcting an established lack. And for many, the side effects outweigh the benefits.

What people need isn't a pill to treat a made-up imbalance. They need connection, meaning, purpose, security, and hope. They need alternatives, not drugs.

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References

1. 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. https://doi.org/10.1038/s41380-022-01661-0

2. Lacasse, J. R., & Leo, J. (2005). Serotonin and depression: A disconnect between the advertisements and the scientific literature. PLoS Medicine, 2(12), e392. https://doi.org/10.1371/journal.pmed.0020392

3. Andrews, P. W., Thomson, J. A., Amstadter, A., & Neale, M. C. (2012). Primum non nocere: An evolutionary analysis of whether antidepressants do more harm than good. Frontiers in Psychology, 3, 117. https://doi.org/10.3389/fpsyg.2012.00117

4. Whitaker, R. (2010). Anatomy of an Epidemic. Crown Publishing.

5. Kirsch, I. (2010). The Emperor’s New Drugs: Exploding the Antidepressant Myth. Basic Books.