Using strict research diagnosis criteria, the authors found a hospital admission prevalence of schizophrenia of about six per cent. Other recent studies yielded similar figures, with correspondingly low figures for the morbid risk of schizophrenia in the general population and in the relatives of schizophrenic probands. In view of the data supporting the validity of this "narrow" concept of schizophrenia, the authors suggest that the true prevalence of schizophrenia is much lower than generally accepted.