Schizophrenia and affective disorder: are they genetically linked?

The relationship between schizophrenic 'spectrum' disorders and affective illness was studied in the nuclear families of 90 chronic schizophrenic probands. An increased risk of schizophrenia and related disorders was demonstrated among the first-degree relatives of probands with a family history of major affective disorders. Conversely, relatives of probands with a family history of schizophrenic 'spectrum' disorders were at a greater risk of affective illness (major depression) than relatives of probands with no family history. These results lend support to the notion that a subset of affective disorders is associated with the liability to schizophrenia.