The easier the trait ascertainment, the larger the available samples; for the alcohol-related trait “drinks per week”, data have been collected in numerous studies. The current largest meta-analysis conducted by the GWAS & Sequencing Consortium of Alcohol and Nicotine use (GSCAN) for an alcohol-related trait concerns drinks per week, included a sample size of 941,280, with 99 risk loci identified (e.g., phosphodiesterase 4B (PDE4B) and cullin 3 (CUL3))15. This quantity/frequency measure tended not to show genetic correlation with other psychiatric traits, similar to AUDIT-C. As for AUDIT-C GWAS results, these quantity/frequency results are of great interest, but of less clear relevance to pathological AUD; much of the information would have derived from behaviour in the normal range.
