Yoruba traditional healers in psychiatry. I. Healers' concepts of the nature and aetiology of mental disorders.

Twenty Yoruba traditional healers specializing in mental disorders were studied. Two main groups of mental disorders were identified, asinwin (psychotic disorders) and ode ori (a less severe disorder with prominent somatic symptoms). The further sub-categorization of mental disorders was largely on an aetiological basis. The most important aetiological factors identified were: the actions of enemies with major emphasis on the deployment of supernatural forces; self-induced disorders, of which cannabis abuse was the most frequently quoted example; soponna (small-pox) and 'hereditary' factors. The healers' beliefs regarding mode of hereditary transmission of mental disorders were very different from those of modern medicine.