Failure to find evidence of schizophrenia in first-degree relatives of schizophrenic probands

The first-degree relatives (N = 199) of DSM-III schizophrenic probands (N = 39) were diagnosed from chart data by a rater who was blind to proband diagnosis. No cases of even "possible" schizophrenia were found. This augments the growing evidence that the genetic component in schizophrenia may be less than was formerly suspected.