While speculative, this interpretation could be viewed as consistent with the current finding that Met carriers showed stronger associations between implicit coping motives and alcohol consumption. Importantly, additional explanations for COMT effects cannot be ruled out. Functional imaging studies suggest that COMT Val158Met modulates neural processing of reward cues, such that Met carries evidence greater activation in prefrontal as well as ventral striatal regions during anticipation and/or receipt of reward-related information (Dreher et al., 2009; Schmack et al., 2008; Yacubian et al., 2007). Further, findings that COMT Val158Met modulates exploratory decision-making in conditions of uncertainty (Frank et al., 2009) and neural activity during response inhibition (Congdon et al., 2009) provide a basis for additional hypotheses as to possible mechanisms of COMT in the context of alcohol use. Finally, given our use of the IAT measure it should be noted that COMT is demonstrated to influence responding on cognitive tasks involving rapid responses and task switching. However, COMT showed no direct associations with IAT performance, which would argue against the possibility that COMT interactions can be attributed to genotype differences in cognitive processing abilities.
