Given the importance of common variation in the etiology of schizophrenia and that 24 of 25 historical candidate genes for schizophrenia explicitly posited and evaluated the role of common variation, it is timely to assess the contributions of this literature to our knowledge of schizophrenia. With the advantages of hindsight (and noting that the authors of this review conducted many candidate gene studies including two in Table 1 20, 21), we offer a number of explanatory hypotheses regarding this literature.
