Schizophrenia and genetics. A Twin Study Vantage Point

The authors' firmly supported conclusion is that genetics does play a major role in the etiology of schizophrenia; that the genes and various environmental factors are each necessary, but not sufficient, conditions for the development of the disorder. Based on admissions, between 1948 and 1964, to one of the largest modern mental hospitals in the world, the Maudsley Bethlem study employed many methodological refinements not found in 'classical' twin studies. Data on the twins and their families came from extensive hospital notes, tape recorded mental status interviews, personality inventories, tests of thought disorder, and a unique, cross national, blind diagnostic study using seven clinicians of both psychodynamic and biological persuasions from the U.K., U.S.A., Sweden, and Japan. These data are fleshed out in a long chapter giving the distilled case histories of the 57 pairs of twins.