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

Abstract

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. K E Y W O R D S asylums, familial transmission, history, psychiatric genetics "[T]he study of madness can contribute, more than the study of any other malady, to the improvement of the general history of heredity and to the determination of the laws it follows. The consumptive, the scrofulous, the gouty are dispersed here and there, and only with a substantial amount of effort and time a singular observer would achieve to collect a sufficient number of observations. The lunatics, in contrast, are assembled by hundreds in the asylums …." (Baillarger, 1844)(as quoted by Gausemeier, 2015, p. 168) One approach to the history of psychiatric genetics is to focus on landmark papers that produced major conceptual or empirical advances in the field. This article takes a different approach. I attempt to characterize the more typical kinds of investigations of the heredity of insanity in mid-19th century Europe. In an effort to be representative (but not exhaustive), four relatively typical studies published from 1841 to 1864 from Great Britain, France, and Germany are investigated. Two are from general asylum reports and two are from published articles focusing on various aspects of the question of heredity.All use, as their primary source of information, records on the family background of hospitalized mentally ill patients' asylums which were the predominant research method at this time (Porter, 2018).Before proceeding with this review, some background is in order.The 18th and early 19th century in Europe saw a large increase of interest in human heredity particularly from a medical perspective (L opez-Beltrán, 1992;Ribot, 1875;Rushton, 2009). Of the many disorders that were examined for heritable influences by 19th-century physicians, insanity was one of the most prominent (...

Ludvig Dahl's psychiatric genetic studies in his 1859 monograph: “Contribution to the knowledge of insanity in Norway”

“…Dahl addresses, in his book, many of the critical extant scientific issues in the young discipline of psychiatric genetics of the mid‐19th century (Kenneth S Kendler, 2021a). Of these, five are worthy of particular comment.…”

“…Early researchers were, for example, interested in whether men or women were more likely to transmit, or were more sensitive to, a hereditary predisposition (HP) to insanity. Other topics explored included the relationship between an HP and recurrence and whether the transmission of mental illness within families was largely homogeneous (i.e., “like transmits to like” in families) or heterogeneous (that close relatives of mentally ill probands had a wide variety of psychiatric conditions) (Kenneth S Kendler, 2021a). The concept of a controlled study–that would test whether psychiatric disorders were concentrated in the families of mentally ill patients compared to an appropriate comparison group–were not considered.…”

“…That is, Dahl not only makes the important observation that familial aggregation alone is not sufficient evidence for the operation of heredity, but he then proposes the specifics of a test for “HP.” To be confident that hereditary factors are at work, he suggests it is necessary to (i) show that the illness is much more common within than outside a family (or large pedigree) and (ii) rule out possible nonhereditary (e.g., environmental) influences. Dahl is here implicitly criticizing much of the prior work in the field which has assumed, with near but not complete uniformity (Kenneth S Kendler, 2021a), that a family history of mental illness in an asylum record constitutes sufficient proof for the operation of hereditary factors.…”

“…As outlined elsewhere (Kenneth S Kendler, 2021a; Porter, 2018), descriptions of the familial nature of mental illness can be dated back to the very beginnings of Western psychiatry in the 1780s. What was originally a series of clinical observations had, by the mid‐19th century, begun to develop a modest research tradition (Kenneth S Kendler, 2021b).…”

Medical genetics in the 19th century as background to the development of psychiatric genetics

“…Our medical authors also expressed interest in the broad question of whether disease risk was more often transmitted to offspring through the father or the mother. This too was a common topic for 19th-century psychiatric genetic investigators (Kendler, 2021a).…”