Fregoli delusion

Fregoli delusion
Classification and external resources
Specialty	Psychiatry
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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.

A person with the Fregoli delusion can also inaccurately recall places, objects, and events. This disorder can be explained by "associative nodes". The associative nodes serve as a biological link of information about other people with a particular familiar face (to the patient). This means that for any face that is similar to a recognizable face to the patient, the patient will recall that face as the person they know.

The Fregoli delusion is classed both as a monothematic delusion, since it only encompasses one delusional topic, and as a delusional misidentification syndrome (DMS), 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 of Fregoli's:

Levodopa, also known as L-DOPA, is the precursor to several catecholamines, specifically of dopamine, epinephrine and norepinephrine. It is clinically used to treat Parkinson's disease and dopamine-responsive dystonia. 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. With prolonged use of levodopa, the delusions occupy almost all of a patient's attention. In experimental studies, when the concentration of levodopa decreases, the number of reported delusions decreases as well. It has been concluded that delusions related to antiparkinsonian medications are one of the leading causes of Fregoli syndrome.

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