Two initial reports demonstrated the feasibility of the CASE paradigm. In the first study, nine adult social drinkers achieved a mean peak breath alcohol concentration (BrAC) of 76.5mg% across repeated free-access sessions (Zimmermann et al., 2008). In a subsequent study of 22 young adult social drinkers, participants with a family history of alcohol dependence attained higher mean peak BrAC (81.6mg%) compared to family history negative participants (50.5mg%) (Zimmermann et al., 2009). The present study sought to further evaluate the CASE paradigm in a sample of young heavy drinkers, with the specific aim of examining OPRM1 in relation to self-administration. Given evidence that OPRM1 relates to subjective responses to alcohol (Ray and Hutchison, 2004, 2007), and that subjective responses relate to laboratory self-administration (de Wit et al., 1989; de Wit et al., 1987), trait and state measures of alcohol sensitivity were also examined. We predicted that participants with the 118G variant would show higher self-administration and greater hedonic responses during self-administration relative to AA homozygous participants. We also anticipated that, irrespective of genotype, greater perceived stimulant effects and lower perceived sedative
