The authors present two reasons for reassessing familial transmission of
schizophrenia: recent major changes in diagnostic criteria and
methodological weaknesses of older studies. Their own study of this subject
employed narrowly defined, operational research criteria; prospective
proband selection; semistructured family interviews; and blind, independent
diagnoses of probands and relatives. For 30 schizophrenic probands they
found an age-corrected morbidity risk in first-degree relatives of 1.61%, a
figure that would only support familial transmission if the true population
prevalence of schizophrenia were .2% or less. The authors conclude that the
case for familial transmission of narrowly defined schizophrenia is weak
and suggest alternative hypotheses.Abstract Teaser