The results of any model testing must be considered in light of the methodology employed. First, while results are generally similar across U.S. and U.K. samples, and while prior studies demonstrated similar results in both upper and lower socioeconomic class subjects (Schuckit et al., 2008b, 2009a), there are many similarities between the U.S. and U.K. The performance of the LR-based model still needs to be determined in additional cultures and the impact of LR may be most robust in heavier drinking environments. Second, it is important to remember that the low LR to alcohol was measured using a retrospective report, and such questions are vulnerable to memory distortions and forgetfulness. Also, LR is only one of several potential measures of how an individual responds to alcohol, and that additional intermediate phenotypes (e.g., alcohol metabolizing enzymes and externalizing conditions) also contribute to the heavy drinking risk. Third, this paper only tested one model of how LR might relate to adverse alcohol outcomes and alternative models may have done equally well in accounting for the interrelationships of variables. Fourth, the current data
