The PGC began on a teleconference in March 2007 between principal investigators who had GWAS funded for Attention Deficit Hyperactivity Disorder (ADHD), bipolar disorder, major depressive disorder, and schizophrenia as part of a Foundation for the NIH initiative (Manolio et al. 2007). Even though, at the time, this project was at early stages and as no psychiatric GWAS had yet been published, we were already concerned about power and hence initiated plans for joint analysis of our results. This effort rapidly expanded to include autism, , the other major psychiatric disorder with a considerable body of GWAS data. Subsequently, all investigators in the field with data for these five disorders (ADHD, AUT, BIP, MDD, and SCZ) were invited to join the PGC. All but one group invited has joined.
