Epilepsy and insanity during the early 19th century. A conceptual history.

During the first half of the 19th century, epilepsy and the insanities were considered as closely related "neurotic" disorders. Under the influence of factors such as the decline of the 18th-century Cullean concept of neurosis, the development of the new descriptive psychopathology, the introduction of statistics, and the availability of longitudinal observations of hospitalized cohorts, epilepsy was redefined as a "neurological" disease by the 1850s. The reaction of psychiatry to the exclusion of the mental disorder as a defining feature of epilepsy manifested itself in the creation of the "masked epilepsy" concept. This notion is behind the later development of categories such as "borderland" and "equivalent," which are still of some relevance to 20th-century views of epilepsy.