blinding of the placebo drink, controlled dosing and BAC achieved, drinks are less palatable than an individual’s preferred drink, and the timing of consumption may be slower or faster than it would be in the natural environment. Despite these caveats, this carefully controlled laboratory study provides evidence of a role of the DAT1 VNTR polymorphism in alcohol response, and supports future examinations of epistatic interactions between DAT1 and OPRM1 genes in larger studies. Validity of these findings would be strengthened by the examination of the same genes in different populations, as well as replication in the same population. Future studies should expand sampling to better address biological variables like sex and racial/ethnic differences, and systematically investigate factors that may influence findings (e.g., magnitude of recent alcohol use and tolerance, co-morbid cigarette smoking or other drug use in heavy drinkers)
