These results demonstrate that the shared genetic basis of psychiatric disorders translates into shared neurobiological mechanisms. To further identify shared neurobiological basis among psychiatric disorders, we defined a set of pleiotropic genes that are associated with more than four psychiatric disorders. Pleiotropic genes were associated with neuronal development and synaptic plasticity, suggesting that inappropriate neuronal activity and regulation may act as key components in the pathogenesis of psychiatric disorders. Pleiotropic genes also displayed mid-gestational and excitatory neuronal enrichment, summarizing the overall pattern of psychiatric disorder-associated genes. Importantly, this characteristic was also observed for pleiotropic genes identified by meta-analysis of eight psychiatric disorders14.
