Community norms of the Muscle Dysmorphic Disorder Inventory (MDDI) among gender minority populations

Abstract

Purpose: Representing the pathological extreme pursuit of muscularity, muscle dysmorphia (MD) is characterized by a pervasive belief or fear around insufficient muscularity and an elevated drive for muscularity. Despite evidence of heightened body image-related concerns among gender minority populations, little is known about the degree of MD symptoms among gender minorities, particularly based on Muscle Dysmorphic Disorder Inventory (MDDI) scores. The objective of this study was to assess community norms of the MDDI in gender-expansive people, transgender men, and transgender women. Method: Data from participants in The PRIDE Study, an existing study of health outcomes in sexual and gender minority people, were examined. We calculated means, standard deviations, and percentiles for the MDDI total and subscale scores among gender-expansive people (i.e., those who identify outside of the binary system of man or woman; n = 1023), transgender men (n = 326), and transgender women (n = 177). The Kruskal-Wallis test was used to assess group differences and post hoc Dunn’s tests were used to examine pairwise differences. Results: Transgender men reported the highest mean MDDI total score (30.5 ± 7.5), followed by gender-expansive people (27.2 ± 6.7), then transgender women (24.6 ± 5.7). The differences in total MDDI score were driven largely by the Drive for Size subscale and, to a lesser extent, the Functional Impairment subscale. There were no significant differences in the Appearance Intolerance subscale among the three groups. Conclusions: Transgender men reported higher Drive for Size, Functional Impairment, and Total MDDI scores compared to gender-expansive people and transgender women. These norms provide insights into the experience of MD symptoms among gender minorities and can aid researchers and clinicians in the interpretation of MDDI scores among gender minority populations.