This study is the largest genome-wide analysis of psychiatric illness so far and the first to provide evidence that specific SNPs are significantly associated with a range of childhood-onset and adult-onset psychiatric disorders. For the five disorders studied, SNPs at four loci—regions on chromosomes 3p21 and 10q24, and SNPs in two L-type voltage-gated calcium-channel subunits, CACNA1C and CACNB2—exceeded the cutoff for genome-wide significance in the primary analysis. The strongest signal was within a region on chromosome 3p21.1. Aggregate polygenic risk scores for a broad set of common variants showed cross-disorder effects for all the adult-onset disorders (bipolar and major depressive disorder, and schizophrenia) and nominally between autism spectrum disorders and both bipolar disorder and schizophrenia.
