In conclusion, findings from this study suggest that the underlying etiology between eating disorder and substance use-related phenotypes is not consistent across traits or levels of substance involvement, extending results from twin studies to a genome-wide SNP approach. Despite the typically high co-occurrence of alcohol, tobacco, and cannabis use, and their genetic overlap (Pasman et al., 2018), the differential patterns seen between the eating disorder and substance use-related phenotypes highlights the uniqueness and complexity of their shared etiology. Additional research using contemporary genomic methods such as cross-disorder association studies could identify the specific loci contributing to this comorbidity. Once loci are identified, additional research that combines polygenic risk scores with measured environmental constructs could enhance the prediction, prevention, and treatment of co-occurring eating disorder and substance use-related traits.
