Family history study of major psychiatric disorders and syndromes.

The family history of major psychiatric disorders was examined among relatives of 193 in-patients fulfilling the Research Diagnostic Criteria (RDC) for Schizophrenia, Unspecified Functional Psychoses, Schizoaffective Disorder, Manic Disorder or Major Depressive Disorder. The morbid risk (MR) for schizophrenia was greater among the relatives of probands with non-affective psychoses whereas the MR for mania was greater among the relatives of probands with affective bipolar disorder. When major psychiatric syndromes were examined, only manic syndrome showed familial aggregation.