Shared Genetic Influences in Psychiatry: Implications for Diagnosis and Comorbidity

A large, multi-disorder genomic analysis of 14 psychiatric disorders finds widespread shared genetic influences and a five-group genetic structure—reframing many diagnostic overlaps as common biology and shifting assessment toward biologic clusters.

The study delineates five major genetic clusters that cut across traditional categories: internalizing (mood–anxiety–PTSD), psychosis-related (schizophrenia–bipolar), neurodevelopmental (autism spectrum disorder–ADHD), compulsive disorders (OCD–anorexia) and substance use disorders. These groupings provide a biologic rationale for symptom overlap that existing diagnostic labels only partly capture.

The internalizing cluster showed particularly high shared risk: major depression, anxiety disorders and PTSD reportedly share a very high proportion of genetic liability.

This pattern supports counseling that emphasizes polygenic risk and pleiotropy—shared variants increase probabilistic risk across a disorder cluster rather than determining a single outcome. Families can be informed that relatives may have elevated risk for a range of related disorders; broad screening across symptom domains is reasonable when family history or presentation suggests it.

Therapeutic and research priorities follow the cluster logic: pursue drug-repurposing across clustered disorders, design stratified cross-diagnostic trials, and validate biomarkers that map to the genetic groups. Near-term items to watch include biomarker validation studies and cross-diagnostic trials that aim to translate genetic clusters into treatment strategies and enrollment criteria.