Development and psychometric evaluation of the Discrimination and Stigma Scale (DISC).

Mental illness is associated with unfair treatment in a number of areas of life. There is currently no psychometrically validated measure that has been developed to specifically focus on such experienced discrimination. This study aimed to finalise the Discrimination and Stigma Scale (DISC) and establish its psychometric properties. The DISC was further developed using (1) service user and interviewer focus groups; (2) reading ease testing; and (3) cognitive debriefing interviews. The revised scale then underwent psychometric testing to establish the following properties: reliability; validity; precision; acceptability; and feasibility. The final 22-item DISC demonstrated good psychometric properties (n=86) including inter-rater reliability (weighted kappa range: 0.62-0.95), internal consistency (α=0.78) and test-retest reliability (n=46) (weighted kappa range: 0.56-0.89). Feasibility, validity and acceptability were also established. In conclusion, the 22-item DISC is recommended for use in measuring experienced stigma and discrimination. Additional work to develop a measure of anticipated stigma is recommended.