De Clérambault Syndrome, Othello Syndrome, Folie à Deux and Variants.

Non-bizarre delusion, defined as a false belief possible although highly unlikely, is the main manifestation of delusional disorders, previously known as paranoia. Based on the predominant delusional themes, 5 main subtypes may be described - erotomanic, grandiose, jealous, persecutory, and somatic. We present here 2 main delusional disorders, the De Clérambault syndrome and the Othello syndrome, and another closely related to the previous ones - Folie à deux. In the De Clérambault syndrome, the main delusional theme is erotomanic type, related to passional delirium where the patient has strong sexual feelings towards another person and has the belief that this other person is deeply in love with him or her. Patients with the Othello syndrome present a delusional disorder of jealous type, a pathological delusion that the partner is unfaithful. In Folie à deux, 2 individuals shared the same psychiatric symptom. However it may be variable, describing variants such as folie imposée or folie simultenée. The risk of aggressive behavior exists in these patients. Knowledge of these syndromes is essential to allow an accurate diagnosis and prompt treatment.