Phenomenological Aspects of Monodelusional Disorders

The monodelusional disorders correspond closely to the Kraepelinian description of paranoia (Kraepelin, 1921), and to the DSM—III—R category of “delusional (paranoid) disorder” (American Psychiatric Association, 1987). The essential feature is a stable delusional system, and the encapsulated quality of the delusion is characteristic. The rest of the personality is notably well preserved, but the delusional system, despite its encapsulation, takes over much of the individual's way of life. There are profound and striking secondary changes in affect, attitude and logic when the patient switches from the normal to the delusional mode or vice versa.