Religion and psychosis: the effects of the Welsh religious revival in 1904-1905.

BACKGROUND Psychotic symptoms have been linked to religious experience, but empirical evidence is scarce. We have investigated the impact of the Welsh religious revival (RR) of 1904-1905 on the number of admissions to the regional psychiatric hospital, their diagnostic features and lifelong course. METHOD All case-notes of patients admitted to the North Wales Hospital between 1902 and 1907 were included. RESULTS There was a significant increase in admissions for brief polymorphic psychoses (BPP; ICD-10: F23.0 and F23.1) in the revival years, but the number of first admissions for other mental disorders did not change. The vast majority of BPP admissions were linked to a revival meeting and did not result in further admissions. CONCLUSIONS Intensive religious experience can lead to transient psychotic episodes. Our data also support the view that BPP triggered by life events rarely lead to chronic mental illness, distinguishing them from other psychoses and supporting the validity of the concept of reactive psychosis.