TL;DR
Although adding biology to the DSM is progress, mental disorders still lack reliable biomarkers, so biological diagnosis faces huge challenges.
The Diagnostic and Statistical Manual of Mental Disorders (DSM) is called the bible of psychiatry. But this bible has never talked biology — it only looks at symptoms.
The upside is a common language; the downside is no objective measures, and diagnosis rests on the clinician's judgement. The 2013 fifth edition was widely slammed — some worried it would turn normal sadness into a disease.
Now the American Psychiatric Association wants to add biology to the next edition. The author, who served on the writing team, was part of that push.
Why psychiatry has no 'blood test'
Other fields have objective markers — diabetes has hemoglobin A1C, heart disease has cholesterol. Psychiatry has none.
Not for lack of wanting. The biology of mental illness is too subtle for today's tools. And it's tangled up with psychology and society — family trauma and genetic risk mix together and are hard to separate.
Plus mental disorders are not single diseases but clusters of symptoms. Anxiety and depression overlap; schizophrenia and bipolar blur. One marker to sort out that mess? Unrealistic.
What biomarkers look like
Still, there are glimmers. In 2025, the FDA approved the first blood test for Alzheimer's biomarkers — a first for a brain and behavior disorder.
There's also immunity: about 30% of depressed patients have high C-reactive protein, which might help pick who responds to which drug.
Genetic risk is coming too — adding up many tiny-effect genes into a 'polygenic risk score' to estimate danger. But these are far from the clinic.
The author says bringing biology into the DSM is a brick-by-brick job. The real dream is when patients walk in with genetic tests, brain scans and bloodwork — that's the day precision psychiatry arrives.
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