European American (EA) and African American (AA) DNA samples were requested and acquired through the NIDA Center for Genetic Studies in conjunction with Washington University and Rutgers University Cell & DNA Repository. Samples from opioid-dependent individuals were acquired from the NIDA Repository Studies 1 (PI: J. Gelernter et al.), 5 (PI: M.J.Kreek), and samples from cocaine-dependent individuals were acquired from Studies 7 (PI: L. Bierut) and 13 (PI: J. Cubells). Opioid-addicted (EA: n=1041; male 66.1%; AA: n=284 male 68%) and cocaine-addicted subjects (EA: n=336; male 50.3%; AA: n=336; male 62%) of EA and AA descent met DSM-IV criteria for dependence.
