In the present study, we sought to identify genes that modify risk for CD by means of a GWAS in family-based and case-control samples of 2,379 European Americans (EAs), including 1,809 subjects with CD, and 3,318 African Americans (AAs), including 2,482 subjects with CD. Multiple independent samples of EAs and AAs (2,549 identically ascertained subjects that we collected and 4,063 subjects from the Study of Addiction: Genetics and Environment (SAGE) dataset) were used to replicate and extend our findings. We identified one novel CD risk locus at genomewide significance (GWS) and numerous others, relevant to CD and the related trait of cocaine-induced paranoia (CIP), worthy of future investigation.
