F24 Induced Delusional Disorder

A rare delusional disorder shared by two or occasionally more people with close emotional links. Only one person suffers from a genuine psychotic disorder; the delusions are induced in the other(s) and usually disappear when the people are separated. The psychotic illness of the dominant person is most commonly schizophrenic, but this is not necessarily or invariably so. Both the original delusions in the dominant person and the induced delusions are usually chronic and either persecutory or grandiose in nature. Delusional beliefs are transmitted this way only in uncommon circumstances. Almost invariably, the people concerned have an unusually close relationship and are isolated from others by language, culture, or geography. The individual in whom the delusions are induced is usually dependent on or subservient to the person with the genuine psychosis.

Diagnostic Guidelines

A diagnosis of induced delusional disorder should be made only if:

(a) two or more people share the same delusion or delusional system and support one another in this belief;
(b) they have an unusually close relationship of the kind described above;
(c) there is temporal or other contextual evidence that the delusion was induced in the passive member(s) of the pair or group by contact with the active member.

Induced hallucinations are unusual but do not negate the diagnosis. However, if there are reasons for believing that two people living together have independent psychotic disorders neither should be coded here, even if some of the delusions are shared.

Includes:
* folie a deux
* induced paranoid or psychotic disorder
* symbiotic psychosis

Excludes:
* folie simultanee