The study of human heredity got its start in insane asylums

Genetics in the Madhouse
Theodore M. Porter
Princeton Univ., $35

England’s King George III descended into mental chaos, or what at the time was called madness, in 1789. Physicians could not say whether he would recover or if a replacement should assume the throne. That political crisis jump-started the study of human heredity.

Using archival records, science historian Theodore M. Porter describes how the king’s deteriorating condition invigorated research at England’s insane asylums into the inheritance of madness. Well before DNA’s discovery, heredity started out as a science of record keeping and statistical calculations. In the 1800s, largely forgotten doctors in both Europe and North America meticulously collected family histories of madness, intellectual disability and crime among the growing numbers of people consigned to asylums, schools for “feebleminded” children and prisons.

Some physicians who specialized in madness, known as alienists, saw severe mental deficits as a disease caused by modern life’s pressures. But most alienists regarded heredity, the transmission of a presumed biological factor among family members, as the true culprit. Asylum directors launched efforts to track down all sick relatives of patients. The increasing number of people institutionalized for mental deficits fueled the view that individuals from susceptible families should be discouraged from reproducing.

Porter documents a mid-1800s push for standardized asylum statistics. Asylum directors turned to the correlation table, which drew statistical links between pairs of variables, such as disease type and percentage of people cured. In 1859, Norwegian researcher Ludvig Dahl published family pedigrees of mental illness, using detailed census records.

Dahl and his predecessors laid the groundwork for well-known statisticians, such as Francis Galton, to launch the eugenics movement by 1900. Gregor Mendel’s plant-breeding experiments raised eugenicists’ hopes that people inherit mental health or illness as systematically as peas inherit smooth or wrinkled skins. That idea was rejected as simplistic by 1920.

German researchers then organized an unprecedented project to collect data on family traits of asylum patients, intellectually disabled students and prisoners. The work expanded under the Nazis. Eugenics’ horrific crescendo didn’t stop investigators worldwide from approvingly citing German work on inheritance for several decades after World War II.

Porter takes a fascinating look at early attempts to tame unruly minds with big data and statistics. Those efforts had some lasting effects. Family pedigrees, for instance, remain part of research into the inheritance of mental disorders. A few sections featuring hereditary tables and family data can be skipped without detracting from the book’s major theme: In an era of molecular genetics, heredity’s statistical history calls for a huge dose of scientific humility.

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