“The Chemical Imbalance in the Brain” is a myth!
For over half a century, the phrase “chemical imbalance” has dominated public understanding of depression. From pharmaceutical advertisements to doctor’s offices, millions have been told that their sadness stems from a deficiency of serotonin—a neurotransmitter believed to regulate mood—and that antidepressants correct this imbalance.
In her book Chemically Imbalanced: The Making and Unmaking of the Serotonin Myth, psychiatrist and researcher Joanna Moncrieff takes a critical look at this narrative. She argues that the serotonin theory of depression, far from being a scientific fact, is a cultural myth that shaped modern psychiatry, pharmaceutical marketing, and our very idea of what it means to be “mentally ill.”
A History of an Idea
The story begins in the 1960s, when early biological psychiatry sought measurable causes for mental disorders. Researchers speculated that mood might be linked to chemicals like serotonin or noradrenaline. Though evidence was always thin, the theory offered a simple, biological explanation for complex emotions—and a hopeful message that brain chemistry could be fixed with medication.
By the 1980s and 1990s, the chemical imbalance hypothesis had become a cornerstone of psychiatric education and public health messaging. The rise of Selective Serotonin Reuptake Inhibitors (SSRIs) like Prozac coincided with a powerful marketing campaign: depression was said to result from low serotonin, and SSRIs were presented as drugs that corrected this deficiency.
The narrative stuck. It was easy to understand, comforting, and scientifically respectable. For many, it provided relief from stigma: depression was no longer a personal weakness but a treatable medical condition.
The Evidence Unravels
However, as Moncrieff demonstrates, the scientific evidence never truly supported the serotonin hypothesis. In 2022, she co-authored a major umbrella review analyzing decades of studies on serotonin levels, receptor activity, and genetic markers. The conclusion was clear: there is no convincing evidence that depression is caused by low serotonin or that antidepressants work by correcting such an imbalance.
This doesn’t mean antidepressants are ineffective. They can alter brain chemistry and may bring emotional relief—but not because they “fix” a known biological defect. Moncrieff argues that the drugs change normal brain states in ways that can blunt emotional pain, similar to alcohol or sedatives, rather than addressing an underlying imbalance.
The Cultural Power of a Myth
Why, then, did the chemical imbalance story endure for so long?
Moncrieff traces its persistence to interlocking interests:
Pharmaceutical companies found it an effective marketing tool.
Psychiatry gained scientific legitimacy by aligning itself with biological medicine.
The public found solace in a clear, medical explanation for suffering.
This convergence turned a tentative hypothesis into a societal truth. It shaped medical practice, influenced policy, and led to an explosion in antidepressant prescriptions worldwide.
Consequences and Questions
The dominance of the serotonin myth, Moncrieff argues, has not been harmless.
Millions of people have taken antidepressants for years without understanding how they work—or the risks of long-term use, dependence, and withdrawal. Meanwhile, non-medical contributors to depression—such as trauma, inequality, isolation, and stress—have been overshadowed by a focus on brain chemistry.
By reframing depression as purely biological, society risks ignoring its psychological and social dimensions. As Moncrieff puts it, “We have medicalised misery.”
Toward a New Understanding
Chemically Imbalanced does not deny that antidepressants can help some people. Rather, it calls for transparency and honesty: that psychiatry admit what is and isn’t known about how these drugs work, and that patients are given a genuine choice in their treatment.
Moncrieff envisions a shift from the reductionist model of “faulty brain chemistry” to a more contextual understanding of human distress—one that embraces social, relational, and existential factors. Mental suffering, she reminds us, cannot be reduced to molecules alone.
Conclusion
Joanna Moncrieff’s Chemically Imbalanced is both historical investigation and cultural critique. It challenges one of modern medicine’s most enduring myths and invites a re-evaluation of how we understand—and treat—depression.
In dismantling the serotonin story, Moncrieff does not leave a void. Instead, she opens space for a richer, more humane vision of mental health—one grounded not in chemical corrections, but in empathy, honesty, and the complexity of being human.
