Abstract
The Hierarchical Taxonomy of Internalizing Dimensions for Eating Disorders model positions eating disorder (ED) symptoms on an internalizing dimension alongside anxiety and mood symptoms. Symptom dimensions falling under the internalizing subfactors of distress (e.g., social anxiety) and fear/avoidance (e.g., panic, compulsions, checking) may differentially guide treatment. We examined relations between fear of negative evaluation and intolerance of uncertainty (core features of social anxiety and obsessive-compulsive disorder, respectively) and ED-related impairment and potential diagnostic differences. We hypothesized that: (a) fear of negative evaluation and intolerance of uncertainty would be related to ED-related impairment, (b) the relation between fear of negative evaluation and impairment would be strongest among individuals with "binge-eating syndromes" (i.e., bulimia nervosa [BN], binge-eating disorder [BED]), and (c) the relation between intolerance of uncertainty and impairment would be strongest among individuals with "weight-phobic syndromes" (i.e., anorexia nervosa [AN], BN, atypical AN). Participants (N = 236) included children/adolescents and adults evaluated for outpatient ED treatment. Participants completed questionnaires and semi-structured diagnostic interviews. Greater fear of negative evaluation and greater intolerance of uncertainty were related to greater clinical impairment, and the strength of these relations depended on ED diagnosis. Fear of negative evaluation was related to impairment among individuals with AN and atypical AN, and intolerance of uncertainty was related to impairment for individuals with AN, BN, and atypical AN. We identified fear of negative evaluation and intolerance of uncertainty as correlates of clinical impairment, highlighting the potential utility of developing treatments to target these internalizing constructs, especially for individuals with weight-phobic syndromes.