To the Editor: Family, twin, and adoption studies conducted over the past several decades have suggested the involvement of genetic factors in normal and pathological behavior. Recent advances in molecular biology have resulted in a tremendous explosion of molecular genetic studies of behavioral disorders and normal personality traits. However, people knew about the inheritance of behavioral traits and psychiatric disorders centuries ago.

Theories about the inheritance of behavior date to ancient Greece. It has been suggested that Hippocrates (460–377 B.C.) was the first to stress heredity and predisposition in relation to mental diseases (1). The relationship between heredity and mental disease was also noted by another ancient scholar—Euripides (484–406 B.C.) (2). Felix Plater (1536–1614) is regarded as one of the earliest classifiers of psychiatric diseases (1). In his effort to study mental illness, he classified behavioral disorders into acquired, congenital, and hereditary afflictions.

Robert Burton (1577–1640) wrote in his book The Anatomy of Melancholy that the "inbred cause of melancholy is our temperature, in whole or part, which we receive from our parents" and "such as the temperature of the father is, such is the son’s, and look what disease the father had when he begot him, his son will have after him" (3). Burton continued, "I need not therefore to make any doubt of melancholy, but that it is an hereditary disease." Garrison (4) noted that "In the Historiettes of Tallemant des Réaux,there are many amusing details about the delusions, obsessions, phobias, fetishisms, and introversions of the nobles, with genealogic tables, signalizing morbid heredity." Gédéon Tallemant des Réaux (1619–1692) was a French writer. His Historiettes is a series of brief anecdotal portraits of persons prominent in the Paris of his day. Phillippe Pinel (1745–1826), one of the founders of modern psychiatry, was accepted in his own day as an outstanding physician (5). Pinel wrote many pages about heredity. In his book on heredity, Pinel said, "It would be difficult not to concede a hereditary transmission of mania, when one recalls that everywhere some members of certain families are struck in several successive generations" (5).

These are just a few examples demonstrating that it has long been recognized that behavioral disorders run in families. Inheritance of behavior is not a new idea. A genetic perspective on the inheritance of behavioral features and disorders was present centuries ago.