HERITABILITY OF SCHIZOPHRENIA - A CONTROLLED FAMILY HISTORY INVESTIGATION IN NIGERIA

Thirty-six consecutively admitted patients with schizophrenia and 20 w ith mania were studied for the morbid risk of psychosis in their first -degree relatives. Using the family history method of ascertainment, t he morbid risk for schizophrenia in the relatives of schizophrenic pro bands was 4.12% compared with 1.42% in the relatives of manic probands . While this difference was not statistically significant, that betwee n the morbid risk for affective psychoses in the relatives of manic pa tients (7.81%) was significantly higher than for the relatives of schi zophrenic patients (0%).