We note a number of limitations to the current report. First and foremost, we did not have data regarding craving and therefore could not construct a formal DSM-5 AUD diagnosis. As noted above, it is unlikely that this introduced substantial bias to our report of prevalence. However, it is possible that the inclusion of a craving item would change the results of the biometrical analyses; we hypothesize that the introduction of a new criterion (as opposed to the exclusion of the LP criterion, and slight changes in the endorsement frequencies for constant criteria) could lead to a lower genetic correlation between the DSM-IV and DSM-5 diagnoses. This possibility should be explored in genetically informative samples for which information on craving is available. We also note that the collinearity of the diagnostic phenotypes used in the twin modeling analyses is not ideal, and can result in unstable parameter estimates. In addition, for some of our analyses, we modeled the sexes jointly, though it is reasonable to expect that sex differences exist. For example, difficulty parameters for each symptom were higher for
