Dementia praecox

Dementia praecox (meaning a "premature dementia" or "precocious madness") is a disused psychiatric diagnosis that originally designated a chronic, deteriorating psychotic disorder characterized by rapid cognitive disintegration, usually beginning in the late teens or early adulthood. Over the years, the term dementia praecox was gradually replaced by the term schizophrenia, which initially had a meaning that included what is today considered the autism spectrum.

The term dementia praecox was first used by German psychiatrist Heinrich Schüle in 1880.^[1]

It was also used in 1891 by Arnold Pick (1851–1924), a professor of psychiatry at Charles University in Prague.^[2] In a brief clinical report, he described a person with a psychotic disorder resembling "hebephrenia" (an adolescent-onset psychotic condition).

German psychiatrist Emil Kraepelin (1856–1926) popularised the term dementia praecox in his first detailed textbook descriptions of a condition that eventually became a different disease concept later relabeled as schizophrenia.^[3] Kraepelin reduced the complex psychiatric taxonomies of the nineteenth century by dividing them into two classes: manic-depressive psychosis and dementia praecox. This division, commonly referred to as the Kraepelinian dichotomy, had a fundamental impact on twentieth-century psychiatry, though it has also been questioned.^[4]

The primary disturbance in dementia praecox was seen to be a disruption in cognitive or mental functioning in attention, memory, and goal-directed behaviour. Kraepelin contrasted this with manic-depressive psychosis, now termed bipolar disorder, and also with other forms of mood disorder, including major depressive disorder. Eventually, he concluded it was not possible to distinguish his categories on the basis of cross-sectional symptoms.^[5]

Kraepelin viewed dementia praecox as a progressively deteriorating disease from which no one recovered. However, by 1913, and more explicitly by 1920, Kraepelin admitted that while there may be a residual cognitive defect in most cases, the prognosis was not as uniformly dire as he had stated in the 1890s. Still, he regarded it as a specific disease concept that implied incurable, inexplicable madness.