Historical review: Autointoxication and focal infection theories of dementia praecox.

The popularity of theories of autointoxication and focal infection in general medicine and dentistry in the late nineteenth and early twentieth centuries led Emil Kraepelin and others to speculate that dementia praecox was caused by a poisoning of the brain from toxins produced in other parts of the body, notably the sex glands, the intestines and the mouth. Emil Kraepelin's commitment to the autointoxication theory is ignored in the literature on the history of psychiatry due to the focus of historians and clinicians on the major contributions of Kraepelin's methods of clinical psychopathology. Besides heredity, autointoxication and focal infection were the other most dominant theories of the organic aetiology of dementia praecox in the first three decades of its existence as a nosological entity in psychiatry. Rational treatments for dementia praecox that followed logically from these aetio-logical theories were colonic irrigations and major abdominal surgeries such as appendicostomies, colectomies and the removal of presumably infected ovaries, testes and other organs associated with reproduction. Autointoxication and focal infection theories disappeared from psychiatry by the mid-1930s.