Introduction to "The Beginnings of Systematic Studies of the Genetics of Schizophrenia: 1916-1933".

Abstract

We here want to introduce this special issue of Schizophrenia Bulletin by providing some background about the history of psychiatric genetics before 1910, the choice of the 5 papers here examined, the methodology we used in writing these papers, the relevance for contemporary psychiatric genetics and a background on our approach to the relationship of the authors of these papers to the eugenic, racist policies of the German National Socialists that led to the large-scale involuntary sterilization of the mentally ill, and the K-4 program of wide-scale murder of mentally ill and handicapped children and adults and the Holocaust. We recommend that interested individuals read the 5 papers in order as this will help them see the historical progression of the methods and results in this early phase of psychiatric genetics research. To appreciate the papers reviewed in this special issue, it is helpful to understand the status of the field of psychiatric genetics circa 1910, before the first important papers based on the rediscovery of Mendel’s work in 1900. K.S.K. has recently written a review paper covering this literature “The Pre-History of Psychiatric Genetics: 1780-1910”,1 which can be consulted by readers interested in this topic. Briefly, in the 19th century, far and away the most common data point used in the psychiatric genetic investigation was a statement in an asylum record of the presence or absence of a “hereditary burden” for the patient, a term broadly congruent with what we might now call a “positive family history.” However, its use was complicated by the fact that across different hospitals, different groups of relatives were included (eg, direct ancestors only, eg, parents and grandparents or direct + collateral including aunts/uncles and potentially siblings), and different conditions were considered as affected (narrowly defined insanity, more broadly defined mental illness, alcoholism, eccentricities, epilepsy, etc.). Few of these relatives were ever personally examined by the alienist recording this information. Common topics of interest at that time included the relationship between a heredity burden and the sex of the patient, the recurrence of episodes of insanity, and the degree of homogeneity versus heterogeneity of transmission of mental illnesses in families.1,2 No formal theories of hereditary transmission were ever examined as the first detailed application of both the biometrical school of Galton and Pearson and Mendelian theory to insanity were not published until the first and second decades of the 20th century.3–8