Alcohol challenges have identified multiple characteristics that contribute to a person’s intensity and type of alcohol responses. Such responses might differ depending on the leg of the blood alcohol concentration (BAC) curve evaluated, attributes of study participants, and alcohol administration protocols. The phenotypes include low levels of alcohol responses (low LRs), most prominent at peak and falling BACs, and high alcohol-related stimulation, typically observed at rising BACs (King et al., 2014; Quinn and Fromme, 2011). These different findings have led to questions regarding whether low LRs can stand alone in predicting later problematic drinking or if the combination of low LR with high stimulation (i.e., a Differentiator Model) is more important (e.g., Newlin and Renton, 2010). I believe both models are correct, with results differing depending on research protocols used. Therefore, this review of genetic variants potentially related to alcohol responses includes data regarding low LR, high stimulation, and their combination.
