For the AA individuals, DNA was collected during clinical and pharmacological trials of cocaine addicted individuals at University of Pennsylvania Treatment Research Center (TRC n = 796, discovery sample) as well as requested from the Rutgers University Cell and DNA Repository (n = 335, replication sample). DNA samples from EA cocaine addicted patients (n = 336) were requested and obtained from the Rutgers University Cell and DNA Repository. Detailed information on the total number of cases and controls for AA and EA populations is summarized in Table 1.
