Based on findings from twin studies, we hypothesized that: 1) the strongest SNP-based rg would be between eating disorder phenotypes that have binge eating as a core symptom and alcohol use phenotypes; and 2) a significant positive genetic correlation between eating disorder phenotypes with binge eating as a key symptom and AUD would emerge. In line with these hypotheses, we found a signifant genetic association between AUD and AN diagnosis, but not between typical alcohol consumption (i.e., drinks per week) and AN. No twin study has examined genetic association between AN and alcohol use-related phenotypes, and previous studies (Walters et al., 2018, Watson et al., in press) using LDSC have not reported significant rgs between these traits. That we found a significant association most likely reflects the larger AN sample size in our study (from 3,495 cases and 10,982 controls to 16,992 cases and 55,525 controls), as well as combining two large existing GWAS of AUD, emphasizing the importance of increasing sample sizes for GWAS.
