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Fregoli Delusion

What is it?

Man with masks

The Fregoli delusion or the delusion of doubles is a rare disorder in which a person holds a delusional belief that different people are in fact a single person who changes appearance or is in disguise. The syndrome may be related to a brain lesion, and is often of a paranoid nature with the delusional person believing themselves persecuted by the person they believe is in disguise.

The condition is named after the Italian actor Leopold Fregoli who was renowned for his ability to make quick changes of appearance during his stage act. It was first reported in a paper by Courbon and Fail in 1927. They discussed the case study of a 27-year old woman who believed she was being persecuted by two actors who she often went to see at the theatre. She believed that these people "pursued her closely, taking the form of people she knows or meets".

The Fregoli delusion is classed both as a monothematic delusion, since it only encompasses one delusional topic, and as a delusional misidentification syndrome, a class of delusional beliefs that involves misidentifying people, places, or objects. Like Capgras delusion, psychiatrists believe it is related to a breakdown in normal face perception.

Signs and Symptoms


Once it has been positively identified, effective pharmacotherapy follows. Antipsychotic drugs are the front runners in treatment for Fregoli and other DMSs. In addition to antipsychotics, anticonvulsant and antidepressants are also prescribed in some treatment courses. If a Fregoli patient has other psychological disorders, treatment often resulted in the use of trifluperazine.


  1. Levodopa treatment
    Clinical studies have shown that the use of Levodopa can lead to visual hallucinations and delusions. In most patients, delusions were more salient than hallucinations. Over prolonged use of levodopa, the delusions almost occupy all of a patient's attention.

  2. Traumatic Brain Injury
    Injury to the right frontal and left temporoparietal areas can cause Fregoli syndrome. Research has shown that significant deficits in executive and memory functions follows shortly after damage in the right frontal or left temporoparietal areas.

  3. Fusiform Gyrus
    Current research has shown that lesions in the right temporal lobe and the fusiform gyrus may contribute to DMSs. MRIs of patients exemplifying Fregoli symptoms have shown parahippocampal and hippocampal damage in the anterior fusiform gyrus, as well as the middle and inferior of the right temporal gyri. The inferior and medial of the right temporal gyri are the storage locations for long term memory in retrieving information on visual recognition, specifically of faces; thus, damage to these intricate connections could be one of the leading factors in face misidentification disorders.

  4. Abnormal P300
    The P300 (P stands for positive voltage potential and the 300 is for the 300 millisecond poststimulus) is an index of WM (Working Memory) and it used during a WM test in DMS patients. In comparison to normal patients, DMS patients generally exhibit an attenuated amplitude of P300 at many abductions. These patients also exhibit prolonged latencies of P300 at all abductions. These implications suggest that DMSs are accompanied by abnormal WM, specifically affecting the prefrontal cortex (both outside and inside).