Genome-wide analyses reveal widespread genetic overlap between neurological and psychiatric disorders and a convergence of biological associations related to the brain.

Neurological and psychiatric disorders are considered to reflect distinct underlying pathogenic entities. However, the extent to which they share genetic influences remains unclear. Here, we performed a comprehensive analysis of GWAS data, involving nearly 1 million cases across ten neurological diseases and ten psychiatric disorders, to compare their common genetic risk and biological underpinnings. Using complementary statistical tools, we demonstrate extensive genetic overlap across the disorders, with varying degrees of genetic correlations. In particular, migraine, essential tremor, stroke and multiple sclerosis were genetically correlated with several psychiatric disorders. Biological interrogation indicated heterogenous biological processes associated with neurological diseases, while psychiatric disorders consistently implicated neuronal biology. Altogether, the study demonstrates that neurological and psychiatric disorders are not genetically disparate, but share key etiological aspects, which have important implications for disease classification, clinical practice, and genomic precision medicine.