Binge eating disorder affects 1-3% of the US population and is the most common eating disorder. The phenotypic associations with binge eating spans both internalizing and externalizing psychopathologies. Further, preliminary analyses from the first genome wide association study (GWAS) of binge eating suggests that binge eating is moderately associated with externalizing outcomes along with internalizing outcomes. The etiology of binge eating is poorly understood; however, we can leverage the genetic overlap between binge eating and other forms of psychopathology to further elucidate its underlying processes and classification as a form of psychopathology.Data were from the first GWAS of binge eating, the multivariate GWAS of externalizing (alcohol problems, cannabis use disorder, smoking initiation, ADHD, risk tolerance, number of sexual partners, and age at first sex) and a multivariate GWAS of internalizing (depression, anxiety, neuroticism, PTSD). First, genetic associations and overlap between binge eating and internalizing and externalizing were estimated. Next, GSEM was used to assess how binge eating fits as an indicator on correlated externalizing and internalizing factors. In order to parse the genetic variance unique to binge eating and shared with the other forms of psychopathology, GWAS were conducted on the binge eating residual and common factor resulting from the GSEM models, and bioannotation was performed on these GWAS. Genetic correlations with external traits were estimated with the common factor and residual GWAS as well as the original binge eating GWAS for comparison. Lastly, exploratory analyses were conducted with binge eating, anorexia, and BMI. Although we find that binge eating is significantly genetically associated with both internalizing and externalizing psychopathology, the associations with externalizing are weaker and seem to be driven by the shared variance with internalizing. Results indicate binge eating is likely associated with internalizing due to transdiagnostic and pleiotropic processes opposed to binge eating being a type of internalizing. This residual binge GWAS yielded three significant loci and the FTO gene had the strongest association. Lastly, there were moderate associations between binge eating, anorexia, and BMI, and the GSEM model of these phenotypes was not cohesive.
Maia Choi (Thu,) studied this question.