Results from approaches (1) and (2) share a number of potential strengths. These datasets provide significant concordance with each other, with previous GWA datasets for substance dependence, and with dbGAP data that has been available only after the results of the current study were analyzed. The arrays used here provide power to identify many of the genes, especially genes of smaller size, which could not have been identified in previous GWA studies that used analysis (1) and lower density arrays [25].
