An International Validation of the Stigma Impact Scale With People With Dementia

TL;DR

This study tested the reliability and validity of the Stigma Impact Scale for measuring self-stigma in people with dementia across 42 countries.

Contribution

The study provides the first international validation of the Stigma Impact Scale in a large, global sample of people with dementia.

Findings

The SIS showed good to excellent internal consistency across its subscales.

Factor analysis suggested a three-factor structure, but validity and fit indices require improvement.

Most SIS items were strongly endorsed, indicating relevance to the dementia experience.

Abstract

A robust psychometric instrument is imperative to measure the devastating impact of self‐stigma in dementia to adequately inform policy and practice. Our objective was to evaluate the psychometric properties of the Stigma Impact Scale in a global sample of people with dementia.

Data were analysed from the World Alzheimer Report including 710 participants in 42 countries who completed the SIS. Detailed psychometric analyses of the SIS included estimating reliability, convergent validity with the Warwick‐Edinburgh mental Well‐being Scale (WEMWBS) and the Dementia Quality of Life instrument (DQoL), the factor structure of the measure (through both exploratory and confirmatory factor analysis).

The SIS and its subscales had ‘good’ to ‘excellent’ internal consistency (Cronbach's Alpha: 0.883–0.943). However, convergent validity correlations were not in the predicted direction; no significant correlations were noted between the SIS and the WEMWBS and DQoL. Factor analysis suggested marginal improvements in global fit indices for the observed model compared to the theoretical model, though none met the thresholds for acceptable fit. The final proposed model had three factors: rejection and secrecy, loneliness and belonging and perceived social isolation. Most SIS items were strongly endorsed by participants.

The SIS is the most robustly tested instrument measuring self‐stigma in dementia. The SIS has good to excellent reliability and relevance to the target population, however future work is required to improve the factor structure of the scale. Further the results of the validity testing pose a number of theoretical and empirical questions for future research.

Measuring self‐stigma in dementia with a robust, validated psychometric instrument would mean we could identify areas of concern for policy and practice.The Stigma Impact Scale (SIS), measuring self‐stigma in dementia, has been a valid and reliable measure in small samples but has never been subject to vigorous psychometric testingAll SIS items were endorsed by approximately 20% or more of people with dementia which suggests SIS items reflect relevant and identifiable constructs that resonate with the experience of dementiaResults of the current study confirm that SIS is a reliable measure in a global sample of people with dementia however validity and factor structure require further research efforts.

Measuring self‐stigma in dementia with a robust, validated psychometric instrument would mean we could identify areas of concern for policy and practice.

The Stigma Impact Scale (SIS), measuring self‐stigma in dementia, has been a valid and reliable measure in small samples but has never been subject to vigorous psychometric testing

All SIS items were endorsed by approximately 20% or more of people with dementia which suggests SIS items reflect relevant and identifiable constructs that resonate with the experience of dementia

Results of the current study confirm that SIS is a reliable measure in a global sample of people with dementia however validity and factor structure require further research efforts.