Measuring feelings of dehumanization in people who experience psychosis: development and validation of the self-Dehumanization in Psychosis Scale (DiPS).

BACKGROUND AND HYPOTHESIS: Self-dehumanization is the experience of feeling less or other than human, and is known to be experienced by people with psychosis. Existing measures of self-dehumanization are limited in their applicability to psychosis, and have not been developed with people with lived experience. The aim of this study was to develop and validate a measure of self-dehumanization in psychosis in partnership with key stakeholder groups.

STUDY DESIGN: Firstly, domains were specified based on review of existing theories of self-dehumanization and qualitative research on self-dehumanization in psychosis. Secondly, items were generated from a systematic literature review of existing measures of self-dehumanization, transcripts from qualitative research on self-dehumanization in psychosis, and lived experience consultations. Third, items were reduced and revised in a Delphi study (n = 49). Fourth, cognitive interviews (n = 9) were conducted to improve comprehensibility and further revise items. Finally, in psychometric validation, the DiPS underwent exploratory and confirmatory factor analysis, item reduction, and reliability and validity assessment (n = 456).

STUDY RESULTS: The 13-item DiPS was developed. Both two- and four-factor solutions were tested; the four-factor solution, comprising Humanity, Identity, Personhood, and Agency, demonstrated optimal fit. The DiPS showed strong construct validity, correlating positively with internalized stigma, paranoid thoughts, and voice-hearing, and negatively with self-compassion. Test-retest reliability and internal consistency were excellent.

CONCLUSIONS: The DiPS is a reliable and valid measure of self-dehumanization in psychosis. This novel measure can be used in research and clinical practice to better understand distress in psychosis.