Facilitating research on eating disorders stigma: validation of the internalised stigma of mental illness scale for use in people with eating disorders

Stigma internalisation in people with eating disorders is an area of increasing scientific interest. To date, however, no measure of stigma internalisation has been validated for use in people with eating disorders, which may help explain the paucity of research investigating stigma in this population. We conducted a confirmatory factor analysis of the 29-item Internalised Stigma of Mental Illness Scale (ISMI) in a sample of 331 individuals with various eating disorders, and further examined its concurrent predictive validity and convergent validity. The original factor structure of the ISMI indicated poor fit. Five modifications were made; one item was excluded, three items had their factor loadings moved to a different subscale, and the co-variance between two items was modelled. The modified ISMI indicated good fit and exhibited evidence of concurrent predictive validity and convergent validity. The ISMI is valid for use in people with eating disorders with minimal changes to subscale scoring. Although relatively few changes to the ISMI were proposed, the capacity to compare ISMI scores across patient populations should be weighed against obtaining empirically and theoretically defensible factor structures that may be population-specific.