Factor structure, internal consistency, and measurement invariance of the Eating Pathology Symptoms Inventory (EPSI) in a national U.S. sample of cisgender gay men and lesbian women

Background: The Eating Pathology Symptoms Inventory (EPSI) is a questionnaire that assesses the severity of eating-disorder symptoms. This study aimed to examine the factor structure and measurement invariance of the EPSI in a large national U.S. sample of cisgender gay men and lesbian women. Methods: The sample consisted of 1,498 cisgender sexual minority adults, including cisgender gay men (n = 925) and cisgender lesbian women (n = 573), who completed online self-report surveys. Using a split-half approach, exploratory factor analysis (EFA) was conducted in the first subset of each sample to identify underlying factor structures, followed by confirmatory factor analysis (CFA) to confirm model fit in the second subset of each sample. Multi-group confirmatory factor analysis (MG-CFA) was used to assess measurement invariance across the two sexual minority groups. Results: The EPSI eight-factor structure was supported across both cisgender sexual minority groups with strong model fit: cisgender gay men (CFI = 0.96, RMSEA = 0.04, SRMR = 0.06) and cisgender lesbian women (CFI = 0.94, RMSEA = 0.05, SRMR = 0.07). Measurement invariance analyses indicated that the EPSI was invariant across groups. Internal consistency, assessed using McDonald’s omega, was acceptable for all scales (ωs = 0.75 to 0.95). Conclusions: This study provides support for the utility of the EPSI in cisgender gay men and lesbian women populations, including measurement invariance that allows for meaningful comparisons across groups. Specifically, the EPSI performs reliably and consistently as a measure of eating pathology across adult cisgender gay men and cisgender lesbian women.