Am J Psychiatry 1976; 133:185-191
Copyright © 1976 by American Psychiatric Association
Estimating the genetic contribution to schizophrenia
SW Matthysse and KK Kidd
The authors discuss the limitations of the concept of heritability in
schizophrenia and, using reported incidence figures, assess two
alternatives--the multifactorial and single major locus (SML) models. Both
models predict genetic heterogeneity in schizophrenia. For some parameter
values, the SML model indicates that homozygotes are rare but at very high
risk. According to the multifactorial model, 9.1% of the schizophrenic
population has a genetic risk of 99% or more. The authors conclude that
neither model adequately accounts for the data but that predictions from
both can be used to design sampling procedures which will increase the
probability of selecting for study individuals whose illness is highly
genetically determined.
