The goal of this review is to evaluate the current status of historical candidate genes for schizophrenia. The motivation is straight-forward: there are hundreds of papers on these genes, several of these genes have motivated considerable biological experimentation, and as recent large-scale studies have expanded our knowledge base, it is reasonable to review this topic. Early candidate gene studies evaluated tens of genetic markers in hundreds of subjects and more recent studies conducted genome-wide comparisons of millions of genetic markers in tens of thousands of subjects. The largest published study is of 34,000 cases from the Psychiatric Genomics Consortium, PGC) which identified 108 genome-wide significant loci. 11
