What it is
Researchers applied a suite of statistical and functional genomic analyses to common-variant association data spanning 14 childhood- and adult-onset psychiatric disorders, drawing on 1,056,201 cases. They identified five underlying genomic factors that account for the majority of each disorder's genetic variance (around 66% on average) and that map to 238 pleiotropic loci. A factor defined by schizophrenia and bipolar disorder was enriched in genes expressed in excitatory neurons, while an internalizing factor spanning major depression, PTSD and anxiety was tied to oligodendrocyte biology.
Why it matters
The analysis gives a data-driven structure to psychiatric comorbidity, showing that disorders long debated as distinct, such as schizophrenia and bipolar disorder, share almost all of their genetic signal with very few disorder-specific loci. Anchoring the factor structure to distinct cell types (excitatory neurons versus oligodendrocytes) points toward a classification grounded in neurobiology rather than symptom checklists.
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Filed underpsychiatric genetics, gwas, comorbidity, pleiotropy, genomic factors