The current study provides further evidence for the feasibility of the CASE paradigm, extending prior research (Zimmermann et al., 2008, 2009) to a sample of young heavy drinkers. Additionally, this study extends prior research on OPRM1 by providing initial evidence for genotype differences in alcohol self-administration using a paradigm characterized by high pharmacokinetic control. Heavy-drinking young adults with the 118G variant achieved higher peak brain alcohol exposure relative to 118A homozygotes, reflecting a greater number of alcohol requests. A similar pattern was observed for secondary self-administration outcomes, although group differences failed to reach significance. A secondary finding was that GA/GG participants triggered the 100mg% safety ceiling more frequently than AA participants, suggesting that the ceiling limited peak BrAC to a greater extent in the GA/GG group.
