Measuring feelings of dehumanisation in people who experience psychosis: Development and validation of the self-Dehumanisation in Psychosis Scale (DiPS)

Background and Hypothesis: Self-dehumanisation is the experience of feeling less or other than human, and is known to be experienced by people with psychosis. Existing measures of self-dehumanisation are limited in their applicability to psychosis, and have not been developed with People with Lived Experience (PLE). The aim of this study was to develop and validate a measure of self-dehumanisation in psychosis in partnership with key stakeholder groups.

Study Design: Firstly, domains were specified based on review of existing theories of self-dehumanisation and qualitative research on self-dehumanisation in psychosis. Secondly, items were generated from a systematic literature review of existing measures of self-dehumanisation, transcripts from qualitative research on self-dehumanisation in psychosis, and consultations with PLE. 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 models were tested; the four-factor solution – comprising Humanity, Identity, Personhood, and Agency – demonstrated optimal fit, and was retained as the final model. The DiPS showed strong construct validity, correlating positively with internalised 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-dehumanisation in psychosis. This novel measure can be used in research and clinical practice to better understand distress in psychosis.