The nature of hereditary influences on insanity from research on asylum records in Western Europe in the mid-19th century.

This article explores the nature of psychiatric genetics research conducted in asylums in Western Europe in the mid-19th century through an examination of four studies published 1841 to 1864 from Great Britain, France, and Germany. They all utilize asylum records to determine if patients had a hereditary predisposition (HP) to mental illness. A diverse range of topics were investigated, with most attention on whether men or women are more likely to transmit, or are more sensitive to the receipt of, an HP. When significant sex effects were seen, they consistently found women to be more likely to transmit and/or more sensitive to the receipt of an HP. Other questions explored included: (a) the relationship between an HP and recurrence rates; (b) the degree of homogeneity versus heterogeneity of transmission of specific mental illnesses in families; (c) the level of HP among different forms of mental illness; and (d) differences in the proportion of psychiatric patients with an HP as a function of their religion. While the method of assessment of familial/genetic risk was relatively crude, even at this early stage in the history of psychiatric genetics, investigators were asking thoughtful questions about the nature and clinical impact of that risk.