Segregation analysis of schizophrenia under a mixed genetic model.

Family data were collected on a multi-ethnic cohort of hospitalized schizophrenics in Hawaii in 1942. Results showed that prevalence rates for Orientals were significantly higher (p less than 0.001) than rates for Caucasians, Polynesians and others. Complex segregation analysis using a generalized mixed genetic model was performed on 507 sibships collected under both complete and incomplete selection. Likelihood ratio tests between the generalized model and two subhypotheses of a major gene effect and a polygenic effect revealed that neither subhypotheses could be rejected at the 5% level of significance. While neither hypothesis could be adequately supported by the likelihood ratio test, certain aspects of the findings suggest a preference for the multifactorial model in explaining the inheritance of schizophrenia in these data.