The Fregoli syndrome, also called as delusion of doubles, is a rare mental condition where an affected person strongly believes that the different people that he encounters are actually just a single individual in disguise. Most of the time, the patient also has this delusion that this impostor in disguise is out to kill him or her. The misidentification in Fregoli delusion is not only limited to people. In a few cases, people with Fregoli delusion can also see different animals, objects, or even places, as the impostor in disguise.
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Levodopa treatment[ edit ] Levodopa , also known as L-DOPA, is the precursor to several catecholamines , specifically of dopamine , epinephrine and norepinephrine.
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.
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. Research by Feinberg, et al. Tests performed on patients that have suffered from a brain injury revealed that basic attention ability and visuomotor processing speed are typically normal. However, these patients made many errors when they were called to participate in detailed attention tasks.
Selective attention tests involving auditory targets were also performed, and brain-injured patients had many errors; this meant that they were deficient in their response regulation and inhibition. The most profound finding in Feinberg et al. They found, however, that these patients chose incorrect answers that were related semantically i. More importantly, tests of visual memory showed that there was a severe inability in visual recollection.
Overall, brain-injured patients were severely impaired in many executive functions such as self-monitoring , mental flexibility , and social reasoning. Fregoli syndrome is an illusion of positive doubles where there is an over-familiarity with the environment. 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.
Recently, a face-specific area in the fusiform gyrus has been discovered and is close to the anterior fusiform gyrus. MRI studies performed by Hudson, et al. Such damage may cause disruption in long-term visual memory and lead to improper associations of human faces. On another note, our brains interpret visual scenes in two pathways: one is via the Parietal lobe - occipital dorsal pathway visual spatial material is analyzed here , and the other is via the temporal -occipital ventral pathway recognizes objects and faces.
Thus, lesions in either structures or disruption of delicate connections may produce DMSs. The integration of information for further processing is referred to as working memory WM.
In comparison to normal patients, DMS patients generally exhibit an attenuated amplitude of P at many abductions. These patients also exhibit prolonged latencies of P at all abductions. These implications suggest that DMSs are accompanied by abnormal WM, specifically affecting the prefrontal cortex both outside and inside.
Past studies have shown correlations between DMS and damages to the right-hemispheric function, which has an array of functions insight, 3D shapes, art awareness, imagination, left-hand control, music awareness, etc.
In recent years, the P auditory component, which forms in response to a detection task that occurs a short time after a stimulus, has acquired a great deal of recognition. The P component is an index of mental activity in that its amplitude increases highly with increased stimuli. This P component is correlated with updating the working memory to what is expected in the environment. Other findings enhance the belief that defects in the working memory are associated with DMS.
Papageorgio et al. Thus, they concentrated on P released during a working memory test in DMS patients. DMS patients were also found to have prolonged P lag, and their memory performance was lower than the control groups. The researchers were, thus, able to imply that DMS patients have trouble in focusing their resources to a stimulus; this was hypothesized to be caused by the neurodegeneration of the right hemisphere.
Overall, other research studies have also provided evidence in the correlation of DMS and gray-matter degeneration of the right frontal region, which controls attentional resources. Antipsychotic drugs are the frontrunners in treatment for Fregoli and other DMSs.
In addition to antipsychotics , anticonvulsants and antidepressants are also prescribed in some treatment courses. If a Fregoli patient has other psychological disorders, treatment often results in the use of trifluoperazine. Courbon and G. She believed these people pursued her closely, taking the form of people she knew or met.
Delusional misidentification syndromes and Fregoli[ edit ] Delusional misidentification syndromes DMS are rooted in the inability to register the identity of something, whether it is an object, event, place or even a person. There are various forms of DMS, such as the syndrome of subjective doubles , intermetamorphosis , Capgras syndrome and Fregoli syndrome. However, all of these various syndromes have a common denominator: they are all due to malfunctional familiarity processing during information processing.
The most common syndromes are Capgras and Fregoli. Capgras syndrome is the delusional belief that a friend, family member, etc. Fregoli syndrome is the delusional belief that different people are in fact a single person who is in disguise. Other commonalities among these syndromes are that they are discriminatory in which object s are misidentified. Lastly, dopamine hyperactivity is evident in all DMSs and thus, all syndromes utilize antipsychotic medications to help control DMS.
Coexistence of Capgras and Fregoli[ edit ] Delusional misidentification syndromes DMSs are four types of syndromes: the syndrome of subjective doubles , the syndrome of intermetamorphosis , Fregoli delusion and Capgras syndrome. Of the four, Fregoli syndrome is the least frequent, followed by Capgras. Of more rarity is the coexistence of both Fregoli and Capgras syndromes.
Coexistence of DMSs are enhanced when coupled with other mental disorders such as schizophrenia, bipolar disorder and other mood disorders. Depersonalization and derealization symptoms are usually manifested in patients exhibiting two misidentification delusions. However, such symptoms have been witnessed to cease once the coexisting DMSs are fully developed. Although there is a plethora of information on DMS, there are still many mysteries of the physiological and anatomical details of DMS.
Popular culture[ edit ] The film Anomalisa has several direct and indirect references to the Fregoli delusion.
The Fregoli delusion: a disorder of person identification and tracking.
Top Cogn Sci. Epub Sep The Fregoli delusion: a disorder of person identification and tracking. To gain a deeper understanding of this contradictory error in the normal system for tracking and identifying known persons, we conducted a detailed survey of all the Fregoli cases reported in the literature since the seminal Courbon and Fail paper. Our preliminary reading of these cases revealed a notable lack of definitional clarity.
Levodopa treatment[ edit ] Levodopa , also known as L-DOPA, is the precursor to several catecholamines , specifically of dopamine , epinephrine and norepinephrine. 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. 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. Research by Feinberg, et al.
Fregoli Syndrome: History, Causes, and Treatments