Drug addiction is a chronic disorder characterized by compulsive drug
seeking and taking despite serious negative consequences. Association
studies have identified a number of candidate genes harboring variants
associated with susceptibility to addiction, but the causative variants
frequently remain unknown. A solution to the challenge of identifying
causative variants is the thorough characterization of functional
genetic polymorphisms and their effects on regulation of candidate
genes. I focused on candidate genes for drug addiction (ARRB2, DRD2, and
DRD3) and made some novel and significant findings: The effects of two
intronic SNPs in the human dopamine receptor D2 (DRD2) gene, previously
shown to alter DRD2 alternative splicing, were confirmed in human brain
autopsy tissues obtained from a population of cocaine abusers and
controls. The same SNPs were significantly associated with cocaine
abuse. The results of this study contribute to our understanding of the
functional genetic variation in important candidate genes and have the
potential to improve the prevention and treatment of drug addiction and
other psychiatric disorders.