Development and validation of a new standardized measure for assessing experiences of discrimination within mental health services. A participatory research project.

Aims: People with mental disorders frequently report experiences of discrimination within mental health services, which can have significant detrimental effects on individuals' well-being and recovery. This study aimed to develop and validate a new standardized measure aiming to assess experiences of stigmatization among people with mental disorders within mental health services.

Methods: The scale was developed in Italian and tested for ease of use, comprehension, acceptability, relevance of items and response options within focus group session. A cross-sectional validation survey was conducted among mental health service users in Italy. Exploratory factor analysis with Promax oblique rotation, the Kaiser-Meyer-Olkin (KMO) measure of sampling adequacy and the Bartlett's test of sphericity were used to assess the suitability of the sample for factor analysis. Reliability was assessed as internal consistency using Cronbach's alpha and as test-retest reliability using weighted kappa and intraclass correlation coefficient (ICC). Precision was examined by Kendall's tau-b coefficient.

Results: Overall, 240 people with mental disorders participated in the study; 56 also completed the retest evaluation after 2 weeks. The 18 items of the scale converged over a two-factor solution ('Dignity violation and personhood devaluation' and 'Perceived life restrictions and social exclusion'), accounting for 56.4% of the variance (KMO 0.903; Bartlett's test p < 0.001). Cronbach's alpha for the total score was 0.934. The scale showed one item with kappa above 0.81, four items between 0.61 and 0.80, ten items between 0.41 and 0.60, two items between 0.21 and 0.40 and only one item below 0.20. ICC was 0.928 (95% CI 0.877-0.958). Kendall's tau-b ranged from 0.450 to 0.617 (p < 0.001).

Conclusions: The newly developed scale represents a valid and reliable measure for assessing experiences of stigma among patients receiving care within mental health services. The scale has provided initial evidence of being specifically tailored for individuals with psychotic and bipolar disorders. However, the factorial structure of the scale should be replicated through a confirmatory factor analysis on a larger sample of individuals with these conditions.