Elucidation of molecular pathogenesis and drug development for psychiatric disorders from rare disease-susceptibility variants.

Recent rapid progress in genome analysis and large-scale consortia has made it possible to discover variants with a variety of allele frequencies and effect sizes associated with psychiatric disorders. Among psychiatric disorder-susceptibility variants, rare variants with large effect sizes detected by sequencing analysis or array comparative genomic hybridization would be particularly useful for elucidating pathophysiology by developing disease models, such as genome-edited mouse or induced pluripotent stem cells. In the last decade, investigations of rare variants with large effect size have revealed an important role of neurodevelopment in the pathogenesis of psychiatric disorders. In future research, integration of recent evidence concerning the contribution of the immune system or gut microbiota will enhance our understanding of psychiatric disorders and facilitate novel drug development.