The public stigma of mental illness means a difference between you and me.

Social desirability can influence reports of stigma change in that subscribing to stigmatizing attitudes might pose a threat to personal beliefs of open-mindedness, while endorsing difference might not be as troubling. A measure is needed that assesses stigma change but is less susceptible to desirability effects. This study examined the psychometrics of various assessments of perceived difference from a person with mental illness. A total of 460 participants were recruited online using Amazon's Mechanical Turk. Four measures of difference, the Likert Scale of Difference, Semantic Differential: Similar-Different Scale, Semantic Differential: Mental Illness versus Other Illness scale, and Cause of Perceived Difference Scale were compared to measures of stereotypes, affirming attitudes, and care seeking. A vignette describing a person with mental illness anchored the Difference Scale and a measure of stereotype. Results showed that measures of difference yielded significantly higher endorsements than measures of stereotypes; the Semantic Differential Scale: Similar-Different was endorsed at a higher rate than other difference scales. Difference scores were positively related to stereotypes and inversely related to affirming attitudes. Difference was also found to influence empowerment separate from, and in addition to stereotype. These results suggest a new domain as an efficient and sensitive measure of stigma change.