Low incidence of schizophrenia in British Columbia coastal Indians.

Schizophrenia rates were obtained from a British Columbia coastal Indian group numbering 14 000. One subgroup numbering 12 200 showed an incidence of 10 cases per 100 000 population a year. An atypical subgroup of 1800 showed an incidence of 49 cases per 100 000 a year. These rates appear to be relevant to a hypothesis that suggests that schizophrenia may be caused by abnormal fatty acid metabolism. A study is reviewed which implies the existence of a delta-5 or delta-6 desaturase enzyme mutation or both, in the Indian population under study.