Paranoid disorder--environmental, cultural or constitutional phenomenon?

At a London hospital the prevalence and types of recorded paranoid disorders, and their characteristics were extracted from the files of in-patients of various cultural groups. It was found that West Indians and Africans had more paranoid colouring in their psychiatric illness than any other group. Other immigrant groups had less paranoid features than the English group. The self or a family member was the commonest focus of intended harm in all the cultural groups. Supernatural modes of injury were common in the West Indians and Africans. It is argued that in immigrants paranoid disorder is not merely due to discrimination consequent on their migrant status, but that cultural factors inherent in the immigrants are also of etiological importance.