Indigenous Spirit Possession Attribution and Psychosis Stigma Among Yoruba Traditional Healers: A Factorial Vignette Experiment on Causal Beliefs and Referral to Biomedical Care

Yoruba traditional healers occupy a pivotal position in the pathways to care for psychosis in south-western Nigeria, yet the causal beliefs they bring to clinical encounters and the referral decisions that follow remain poorly characterised. A 2 × 2 × 2 between-subjects design manipulated causal attribution (spirit possession versus biomedical), symptom severity (acute versus chronic), and help-seeking history (first episode versus recurrent) across 240 healers. Spirit possession attribution increased social distance and perceived dangerousness relative to biomedical attribution, and reduced the odds of referral to biomedical care. The effect on referral was mediated by stigma, and was strongest for chronic presentations and for healers with lower exposure to biomedical training. The findings suggest that attribution and stigma operate as linked mechanisms rather than independent barriers, and that interventions targeting referral must address the meaning healers assign to possession rather than merely supplying biomedical information.