When psychiatrists evaluate identical patient cases, diagnostic agreement occurs in only 55% of instances, according to research from the University of Copenhagen. The study involved 1,038 psychiatrists and physicians from 19 countries who reviewed nine written patient case descriptions.
The findings reveal persistent challenges in psychiatric diagnosis despite decades of standardization efforts. As Professor Julie Nordgaard states: “Our study shows that when two psychiatrists diagnose the same patient, they will agree only 55% of the time.”
The research identified particularly high disagreement rates for schizophrenia spectrum disorders. Overlapping symptoms across conditions—such as obsessive thoughts appearing in both OCD and schizophrenia—contribute to diagnostic variability.
The uncertainty extends beyond clinical implications. Professor Mads Gram Henriksen notes that “diagnostic uncertainty also threatens the reliability of some kinds of psychiatric research.”
The researchers recommend developing more precise disorder descriptions and potentially streamlining diagnostic categories from the WHO’s ICD-10 system, which contains over 200 diagnoses.
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Source: University of Copenhagen
Journal: Frontiers in Psychiatry
DOI: 10.3389/fpsyt.2026.1891625