The present findings must be interpreted in light of the study’s strengths and limitations. Strengths include the highly controlled alcohol administration procedures and the addition of a saline control. The clinically ascertained sample of alcohol dependent patients and the prospective genotyping also strengthen the study’s conclusions. Study limitations include the small sample size, which was sufficient for testing the primary hypotheses, but did not permit subgroup analyses by race or sex. Additionally, the dose of alcohol, while shown to have the expected effect on subjective responses, was relatively modest and additional studies testing higher alcohol doses are warranted, particularly in alcohol dependent samples for which the development of tolerance is an issue. Of note, the diagnostic symptom of tolerance was met by 84% of participants such that analyses of its effect of subjective responses to alcohol were largely underpowered. Another limitation is the fact that participants accurately guessed the alcohol and saline conditions, thereby raising the potential for expectancy effects. At least one study has found that G-allele carriers report greater expectancy for the rewarding effects of alcohol (i.e., drinking
