The authors assessed the relevance of narrowly defined diagnostic
criteria to genetic research in schizophrenia in the nuclear families of 84
chronic schizophrenic probands compared with families of 90 normal control
probands. The morbidity risk for narrowly defined schizophrenia in
first-degree relatives of patients with the narrow diagnosis was
significantly higher than the control rate (3.8% versus 0.3%). The rate of
chronic schizophrenia in the relatives of all schizophrenic patients was
also significantly higher than the control rate (7.1% versus 0.6%), as was
the rate of "spectrum" disorders (33.4% versus 11.3%). The data support the
case for familial transmission of narrowly defined schizophrenia.Abstract Teaser