Activation of the kappa-opioid receptor (KOR) has canonically been associated with negative affective states (Jacobson et al. 2020a; Land et al. 2008) and has been implicated in conditions that include anxiety disorders (Khan et al. 2022; Limoges et al. 2022), alcohol use disorders (Ozkan-Kotiloglu et al. 2023; Park et al. 2020), and eating disorders (Engin 2024; Hasan and Hasan 2011; Karkhanis et al. 2017). This evidence concerns the gene OPRK1 and eating disorder.