As this page from an 1852 asylum report confirms, nineteenth-century medical opinion attributed mental disturbance to a bewildering array of causes. These included sudden shock, grief, religious excitement, masturbation, jealousy, adultery, intemperance, unrequited love and excessive study. This broad range of causes was grouped into two general categories: organic and moral. Organic causes were physical injuries to the brain, such as a blow to the head, and moral causes included emotional upsets, extreme behaviour or immoral conduct. The distinctions were not always rigid; for example, excessive use of alcohol might be responsible for physical damage to the brain. And both organic and moral causes were also classified as either predisposing, those that weakened the mind, or exciting, those that actually addled it.
As practitioners became exposed to more cases of mental illness, opinions about the causes of insanity changed. Doctors grew less likely to invoke single causes, tending to blame a variety of factors instead. They came to see the roots of insanity reaching deeply into the history of individual personality rather than lying exposed on the ground of recent experience. By 1900 most psychiatrists believed that the major predisposing cause of mental illness was the "heredity taint." Constitutions initially weakened by poor heredity were thought to be vulnerable to the secondary causes.
Courtesy: Public Archives of Canada (MG 28l165 Vol. 14)
