The Transmission of Schizophrenia

All experts are agreed that schizo-phrenia is commoner among the relatives of schizophrenic patients than it is in the general population. Many are agreed that other abnormalities are commoner as well, but there is less consensus as to what, precisely, these abnormalities are. Most disagreement has arisen over the mode of transmission of abnormality, the two main types of theory being genetic (transmission via one or several genes) and social (transmission by learning from an abnormal social environment). Controversy has often been bitter and it has sometimes appeared that opposing points of view were irreconcilable. Eminent exponents of both types of theory were brought together in the symposium reported in this book, and the result is a fascinating and readable exchange of information and ideas which not only clears the air but will do a great deal to determine future lines of research. in two masterly chapters, review the evidence for a genetic factor in transmission, and find it convincing. None of the other contributors questions this conclusion and, indeed, the results of family studies, twin studies and adoption studies all tend to confirm it. The environmentalists at the meeting did not dispute the matter and it may be regarded as no longer controversial. The mode, or modes, of inheritance remain to be elucidated , and it is clear that the merits of single versus multigene theories, or of genetic homogeneity versus genetic heterogeneity, cannot yet be decided. Lidz, Wynne, Alanen and others contribute chapters on their studies of family dynamics and communications which do not lead so overwhelmingly to a single conclusion, since it is not clear how far the operation of a genetic factor would explain their results and how much remains over to be interpreted in other terms. Taken together with other evidence, however, it seems clear that many people do not develop schizophrenia, even though they have the genetic constitution to do so, and that environmental causes are therefore of the first importance. John Clausen contributes a very useful discussion of this evidence, and, again, the conclusion seems hardly a matter for argument. The mode of environmental precipitation and the mechanisms whereby hereditary and environmental factors interact remains un