Religion and psychosis: the effects of the Welsh religious revival in 1904-1905.
Psychological Medicine August 1, 2010 S C Linden, M Harris, C Whitaker et al.
During the Welsh religious revival of 1904-1905, admissions to the North Wales Hospital for brief polymorphic psychoses (BPP) increased significantly, while first admissions for other mental disorders did not change. Most BPP admissions were linked to a revival meeting and did not result in further admissions. Intensive religious experience can lead to transient psychotic episodes, and BPP triggered by life events rarely lead to chronic mental illness, supporting the concept of reactive psychosis.