Smith LR, et al. - Researchers examined the MMT-SMS, a theory-based stigma measure, regarding its factor structure, internal reliability, construct, and criterion validity. Further, they compared this measure with the Substance Use Stigma Mechanism Scale (SU-SMS), a self-report questionnaire, to assess experiences of anticipated, enacted, and internalized stigma regarding substance use history. They surveyed 93 participants who were receiving MMT [average daily methadone dose of 84.8mg/day (SD = 28.4mg/day)] at the beginning and end of a prospective study and further they recorded drug use and treatment attendance during that study. Three dimensions reflecting experiences of anticipated (9 items), enacted (9 items), and internalized stigma (7 items) specifically related to receiving MMT were assessed via using a self-report questionnaire in the MMT-SMS. In this sample of persons, the MMT-SMS was identified to be a reliable measure of methadone maintenance treatment stigma with robust validity. As per confirmatory factor analysis, the 7-factor scale structure was supported, distinguishing between experiences of anticipated, enacted, and internalized stigma, and anticipated and enacted stigma source subscales. Regarding criterion validity: there was an association of anticipated MMT and enacted substance use stigma with past 30-day heroin injection, a unique association of MMT stigma with opioid use behaviors while receiving MMT, and broad association of substance use stigma with injection-related behaviors.