Tracing the Roots of Dementia Praecox: Charles Lasègue and his 1852 Essay "Du Délire De Persécutions" (On Persecutory Delusions).

While the evolution of our modern concepts of mania and melancholia over the 19th century is relatively well-understood, no such clear narrative exists for the nonaffective psychotic syndromes that culminated in Kraepelin's concept of dementia praecox in 1899. These narratives were relatively distinct in Germany and France. An important milestone in the French literature is the 1852 essay by the alienist and polymath Charles Lasègue which contained the first detailed modern description of a persecutory delusional syndrome. Lasègue was a careful clinical observer who emphasized a symptomatic approach to psychiatric nosology and was less concerned with course and outcome. He details the evolution of persecutory delusions from increasing referential observations of real events, to the resulting anxious confusion and then the emergence of explanatory delusional beliefs. Once formed, these beliefs, he notes, are relatively impervious to correction. Lasègue was unusual for his time in emphasizing a "first-person perspective" on psychotic experiences, and quotes from his patients in his case history, of which he presents 15. Of these, 12 had auditory hallucinations and 4 passivity phenomena. While conceptualized differently than mid-19th century pre-Kraepelinian German writing on delusional syndromes, and unique on its focus on persecutory delusions, Lasègue's important essay shared a common view on the key features of a broad nonaffective delusional-hallucinatory syndrome. It was this syndrome that Kraepelin, over multiple drafts in the first 6 editions of his textbook from 1883 to 1899, was to divide into his mature concepts of paranoia and the paranoid subtype of dementia praecox.