We underscore the recommendation that investigators consider using standardized approaches to assessing phenotypes for AUD, as well as environmental features of interest for GxE studies. For example, while screening instruments are efficient in terms of time of administration, they typically only approximate the detailed information that can be obtained via a standardized diagnostic interview. Similarly, different formal diagnostic systems do not provide an exact overlap when identifying ‘affecteds’, e.g., Diagnostic Statistical Manual (DSM) diagnoses versus International Classification of Diseases (ICD) diagnoses. These variations in phenotype introduce additional variance that can complicate direct comparisons across studies. Conversely, greater consistency offered by standardization of assessments can facilitate the merging of data sets and meta-analysis of genetic and environmental findings 14. This is one feasible strategy for generating the larger sample sizes needed to study genetic effects for AUD and to disaggregate gender by race/ethnicity differences and major racial/ethnic groups into potentially important subgroups.
