Co-occurring weight- and/or shape-motivated restriction in 5,747 adults with probable avoidant/restrictive food intake disorder.

Objective: According to DSM-5-TR, avoidant/restrictive food intake disorder (ARFID) cannot be diagnosed alongside anorexia nervosa (AN), bulimia nervosa (BN), or any other body image disturbance. This does not accurately reflect real-world symptomatology and recent research, indicating the potential need to revise DSM-5-TR Criteria. We investigated the co-occurrence of weight- and/or shape-motivated restriction (WSR) in adults who screened positive for ARFID, providing evidence to inform such changes.

Methods: The sample comprised 5,747 adults who consented to participate in the ARFID-Genes and Environment (ARFID-GEN) research study, screened positive for ARFID on the NIAS and PARDI-AR-Q, and completed the EDE-Q. We placed our participants into four groups: groups one and two screened positive for AN (ARFID-AN; n=147) or BN (ARFID-BN; n=193), group three endorsed WSR without meeting AN or BN criteria (ARFID-WSR; n=2,097), and group four endorsed ARFID symptoms only (ARFID-nWSR; n=3,310). We used generalized linear models to test group differences on the NIAS, PARDI-AR-Q and EDE-Q.

Results: ARFID-nWSR showed lower scores than all other groups across most ARFID dimensions on the NIAS and PARDI-AR-Q, and lower odds of meeting DSM-5-TR Criteria A1 to A4 (i.e., weight loss; nutritional deficiencies; dependence on nutritional supplements; significant interference with psychosocial functioning).

Discussion: These findings indicate a mixed phenotype with features of both ARFID and WSR associated with more severe ARFID symptomatology. The DSM-5-TR Criteria may not capture complex real-world symptomatology in adults with probable ARFID, potentially precluding those with the most severe symptoms from receiving accurate diagnoses and appropriate care.