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4SNPs. Disease-associated rare variants have been detected mainly by whole-exome sequencing using massively parallel sequencing technology (so-called next-generation sequencing). Exome sequencing can detect variants in the exonic regions (protein-coding regions), including brand-new variants yet known before, but the cost of this technology is higher than SNP chips. The technical details of these technologies are themselves interesting, but they are beyond the scope of this Review. The technical details of such genomic technologies, including newer technologies, are reviewed else-where9, 10).The current psychiatric genomic investigation is advancing following this framework. We are now harvesting the fruit of the genomic analysis of psychiatric disorders to understand the biological mechanisms of psychiatric disorders11, 12). Directly investigating the human brain is ethically and tech-nically challenging. Biological insight from genetic studies complements this difficulty by providing indirect evidence for the etiology of psychiatric disorders. I review the major advancement of psychiatric genetics in the last decade, focusing on significant works on schizophrenia and autism spectrum disorder (ASD), and our investigation on bipolar disorder.Figure 1　A schematic illustration of the disease-associated variants. The x-axis is the allele frequency in the general population, and the y-axis is the effect size to the target disease (e.g., odds ratio). Note that this illustration is a theoretical framework, and there are exceptions to this framework in reality.Schizophrenia is a severe psychiatric disorder characterized by auditory hallucinations and perse-cutory delusions. Schizophrenia afflicts around one percent of the general population, afflicting the patients with painful experiences and social dysfunction due to cognitive decline. Schizophrenia is regarded as one of the major global medical issues because the societal cost of schizophrenia is high among other medical diseases1). Schizophrenia has long been the most major disease concept in psychiatry and is also intensively investigated in genomic research. The prevalence of around one percent is on the threshold of common or rare diseases. Thus, genomic investigation of schizo-phrenia is advancing under two models: research to common variants as common diseases and rare variants as rare diseases.Several hundred common variants associated with schizophrenia have been elucidated from the GWASs of international collaboration using SNP chips13-16). Psychiatric Genomics Consortium (PGC) is the most influential international collaboration of psychiatric genomics17), reporting several signifi-cant results13-15). Precisely speaking, the associated common variants are not always the direct cause of the association but represent the genomic loci Schizophrenia