What if psychiatry’s greatest challenge is not that it knows too little, but that it repeatedly believes it knows more than it does?
In 2019, historian of science Anne Harrington published Mind Fixers: Psychiatry’s Troubled Search for the Biology of Mental Illness. It was not a denunciation of psychiatry, nor was it an argument against neuroscience. Rather, it was a historical examination of a recurring pattern: psychiatry’s repeated search for a biological master key that would finally explain mental illness.
Reading the book in 2026 is a fascinating experience. Much has changed. Yet some of Harrington’s central observations have become even more relevant.
The story is not one of scientific failure. It is a story about the difficulty of understanding the most complex object we know: the human mind.
The Revolution That Didn’t Quite Arrive
For decades, psychiatry invested heavily in genetics, neuroscience, brain imaging, and psychopharmacology. The expectation was that these fields would eventually reveal the biological foundations of disorders such as depression, schizophrenia, bipolar disorder, anxiety, and ADHD.
That expectation was not unreasonable. Yet as of 2026, psychiatry still lacks objective biological tests for most major psychiatric diagnoses.
A cardiologist can often identify heart disease through imaging and laboratory measurements. An oncologist can identify cancer through pathology and genetic testing. Psychiatry largely remains dependent on symptom patterns, clinical interviews, behavioral observation, and patient narratives.
This reality does not invalidate psychiatric disorders. People suffer. Disorders exist. The challenge is that describing suffering and explaining suffering are not the same thing.
Harrington’s critique was aimed precisely at this distinction.
The Decline of the Chemical Imbalance Narrative
Perhaps no psychiatric idea entered popular culture more successfully than the claim that depression results from a chemical imbalance, often framed as a deficiency of serotonin.
The explanation had obvious appeal. It reduced stigma. It sounded scientific. It provided a straightforward narrative.
Unfortunately, reality appears to be considerably more complicated.
Over the past several years, the psychiatric profession itself has become increasingly cautious regarding simplistic serotonin explanations. Researchers continue to investigate biological mechanisms, but few serious scholars now believe depression can be reduced to a single neurotransmitter deficit.
The lesson is not that biology is irrelevant. The lesson is that biology may be vastly more complex than the stories we tell about it.
A theory can be useful without being complete. A diagnosis can be clinically helpful without fully explaining the person who carries it.
Psychiatry’s Return to Humility
One of the most encouraging developments since Mind Fixers was published is the growing humility visible throughout parts of psychiatry and neuroscience.
The confidence of the 1990s and early 2000s often suggested that a biological breakthrough was imminent. Today, researchers more openly acknowledge uncertainty.
Large genetic studies reveal extraordinary complexity. Neuroimaging findings often fail to produce simple diagnostic categories. Mental illness increasingly appears less like a collection of discrete diseases and more like overlapping patterns involving biology, development, psychology, environment, and social context.
This is not scientific weakness. It may represent scientific maturity. The willingness to say “we do not yet know” is often a sign of progress.
The Return of Context
One notable shift since 2019 is the increasing recognition of trauma, loneliness, chronic stress, adverse childhood experiences, social isolation, and economic conditions.
Psychiatry is gradually moving toward a more genuinely biopsychosocial understanding of mental health.
This change matters. Human beings do not exist as isolated brains floating through space. We exist within families, communities, cultures, institutions, and histories.
Any explanation of mental illness that ignores these dimensions risks becoming incomplete. The question is no longer whether biology matters. The question is whether biology alone can ever explain what it means to suffer.
Beyond Biology: The Question of Agency
This observation intersects with questions I have explored elsewhere on this blog. In “What Is Agency? Do We Need To Define Agency?”, I considered how modern discussions frequently reduce human beings to mechanisms while neglecting the role of participation itself.
Mental health presents this challenge clearly.
To emphasize agency is not to deny mental illness. It is not to suggest that depression, anxiety, addiction, or psychosis are matters of simple choice. Rather, it is to recognize that human beings are not passive objects.
People interpret their experiences. People construct meaning. People respond to suffering. People participate in their own becoming.
A diagnosis may describe a pattern of distress. It does not fully capture the experience of being the person living through it.
Two individuals can satisfy identical diagnostic criteria while inhabiting profoundly different worlds. This reality is difficult to quantify, yet impossible to ignore.
The Limits of Definitions
A second theme that emerges from both Mind Fixers and contemporary debates concerns the limits of explanation itself.
In “When A Robot Expressed Consciousness”, I explored the distinction between describing a phenomenon and understanding the phenomenon itself.
Psychiatry faces a similar challenge. Definitions are useful. Diagnostic categories are useful. Neurochemical models are useful. But usefulness should not be mistaken for completeness.
Throughout its history, psychiatry has repeatedly mistaken a successful framework for a complete explanation. The result has often been intellectual overconfidence.
The lesson of history is not that theories are wrong. The lesson is that theories are tools. Reality is always larger than the models we construct to understand it.
New Treatments, Familiar Questions
The rise of ketamine therapies, psychedelic-assisted treatments, and AI-driven psychiatric research has introduced fresh excitement. Some of these developments may prove transformative.
Yet they also raise an old question: does a treatment’s effectiveness validate a theory?
Not necessarily.
Medical history contains many examples of therapies that worked long before scientists understood why. Psychiatry may once again be entering a period where treatments advance faster than explanations.
That possibility should encourage curiosity rather than certainty.
The Enduring Temptation of Grand Narratives
One of the deepest insights in Mind Fixers concerns the human attraction to grand narratives.
- Psychoanalysis
- Behaviorism
- Chemical imbalance theory
- Biological psychiatry
- Precision psychiatry
Each offered genuine insights. Each also promised more than it ultimately delivered.
The danger is not error. Science requires error. The danger is forgetting that our explanations are provisional.
Every generation believes it has finally discovered the missing key. History consistently suggests otherwise.
Toward a More Mature Psychiatry
If there is a lesson worth carrying forward into the next decade, it may be this: the future of psychiatry is unlikely to be found in a single master explanation.
The mind is simultaneously biological, psychological, developmental, social, cultural, and experiential. Any serious account of mental illness must grapple with all of these dimensions.
This approach is less satisfying than a neat theory. It is harder to market. It generates fewer headlines. Yet it may be closer to reality.
The enduring value of Anne Harrington’s work is that it reminds us of a principle that extends far beyond psychiatry.
Intellectual progress often begins not when we discover certainty, but when we become aware of the limits of our certainty.
And perhaps nowhere is that lesson more important than in the study of ourselves.
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References
- Harrington, Anne. Mind Fixers: Psychiatry’s Troubled Search for the Biology of Mental Illness. W.W. Norton & Company, 2019.
- Moncrieff, J., Cooper, R. E., Stockmann, T., et al. “The Serotonin Theory of Depression: A Systematic Umbrella Review of the Evidence.” Molecular Psychiatry, 2022.
- Insel, Thomas. Healing: Our Path from Mental Illness to Mental Health. Penguin Press, 2022.
- Kendler, Kenneth S. “The Nature of Psychiatric Disorders.” World Psychiatry.
- American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision, 2022.
- National Institute of Mental Health, Research Domain Criteria Initiative.