Development and validation of the Eating Pathology Symptoms Inventory (EPSI).

TLDR

Many existing eating disorder measures suffer from inconsistent factor structures and poor discriminant validity. The study aimed to create a comprehensive, multidimensional instrument that overcomes these limitations. An initial 160‑item pool covering 20 dimensions was tested in student and community samples (N = 840) with exploratory and confirmatory factor analyses, then refined and administered to independent samples of specialty ED patients, outpatient psychiatric patients, and students. The resulting 8‑factor structure—Body Dissatisfaction, Binge Eating, Cognitive Restraint, Excessive Exercise, Restricting, Purging, Muscle Building, and Negative Attitudes Toward Obesity—exhibited excellent convergent, discriminant, and invariance properties, with internal consistency alphas of .84–.89 and 2‑ to 4‑week retest reliability of .73, marking it as one of the most comprehensive ED scales developed.

Abstract

Many current measures of eating disorder (ED) symptoms have 1 or more serious limitations, such as inconsistent factor structures or poor discriminant validity. The goal of this study was to overcome these limitations through the development of a comprehensive multidimensional measure of eating pathology. An initial pool of 160 items was developed to assess 20 dimensions of eating pathology. The initial item pool was administered to a student sample (N = 433) and community sample (N = 407) to determine the preliminary structure of the measure using exploratory and confirmatory factor analyses. The revised measure was administered to independent samples of patients recruited from specialty ED treatment centers (N = 158), outpatient psychiatric clinics (N = 303), and students (N = 227). Analyses revealed an 8-factor structure characterized by Body Dissatisfaction, Binge Eating, Cognitive Restraint, Excessive Exercise, Restricting, Purging, Muscle Building, and Negative Attitudes Toward Obesity. Scale scores showed excellent convergent and discriminant validity; other analyses demonstrated that the majority of scales were invariant across sex and weight categories. Eating Pathology Symptoms Inventory scale scores had excellent internal consistency (median coefficient alphas ranged from .84-.89) and reliability over a 2- to 4-week period (mean retest r = .73). The current study represents one of the most comprehensive scale development projects ever conducted in the field of EDs and will enhance future basic and treatment research focused on EDs.