Taking a Deeper Dive Into OSFED Subtypes: A Meta‐Analysis and Systematic Review

ABSTRACT Objective To compare all other specified feeding or eating disorders (OSFED) groups (atypical anorexia nervosa [AN], purging disorder [PD], night eating syndrome [NES], subthreshold bulimia nervosa [sub‐BN], and subthreshold binge‐eating disorder [sub‐BED]) to threshold eating disorders (EDs [AN, BN, and BED]) and control groups (CGs) on measures of eating and general psychopathology. Method We conducted a comprehensive search in PsycINFO, Medline, Embase, and CINAHL on all published studies from January 2013 to February 2024 using DSM‐5 diagnostic criteria via clinical interviews or well‐established diagnostic tools. We also undertook a quality appraisal using an adapted version of the Downs and Black criteria and registered the review with PROSPERO (ID: CRD42022314495). Results Overall, our meta‐analyses (n = 33 eligible studies) indicated that the combined OSFED and several specific OSFED subtypes displayed comparable levels of eating psychopathology to full‐threshold EDs. Our systematic review (n = 33 eligible studies) found individuals with OSFED to have comparable levels of eating and general psychopathology to full‐threshold EDs, but higher levels of eating and general psychopathology than CGs. These findings were specifically attributed to atypical AN and NES. There was a lack of evidence available for sub‐BN and sub‐BED. Studies mainly met the quality appraisal criteria. The main limitations identified in the included studies were insufficient reporting of their statistical power (78%) and no adjusting for potential confounding factors (67%). Discussion Findings support the conceptualization of atypical AN, and NES as clinically significant EDs with similar severity to full‐threshold EDs.