Comorbidity Between Internalizing Symptoms and Disordered Eating Is Primarily Driven by Genetic Influences on Emotion Regulation in Adult Female Twins

Internalizing (e.g., anxiety, depression) and disordered eating (DE; e.g., binge eating, dietary restraint) are highly comorbid, but the mechanisms underlying their comorbidity remain unknown. This was the first twin study to examine whether their co-occurrence may be driven by genetic and/or environmental influences on emotion regulation (ER; ability to modulate duration/intensity of emotions). Analyses included 688 adult female twins from the Michigan State University Twin Registry. Cholesky decomposition twin models showed that comorbidity between dimensionally modeled internalizing and DE was due to overlapping genetic ( r = .55; 69.3% of shared variance) and nonshared environmental influences ( r = .26; 30.7% of shared variance). When ER was added into the model, all genetic influences shared between internalizing and DE were attributable to ER, suggesting genetic influences on ER are the primary driver of comorbidity between internalizing and DE. Shared genes may shape affective processing, interoceptive sensitivity, or other brain-based processes (e.g., cognitive control) implicated in ER.