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 replicate 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. 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,
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
Signs and symptoms of Fregoli's: delusions
visual memory deficit deficit in self-monitoring
deficit in self-awareness hallucinations
deficit in executive functions deficit in cognitive flexibility
history of seizure activity epileptogenic activity
Causes = Levodopa treatment =
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. Over prolonged use of levodopa, the delusions almost occupy
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.
= Traumatic brain injury = Injury to the right frontal and left
temporo-parietal areas can cause Fregoli syndrome. Research by Feinberg, et al.
has shown that significant deficits in executive and memory functions follow
shortly after damage in the right frontal or left temporoparietal areas.
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.'s paper is that performance tests on the retrieval process of memory was
significantly damaged in brain-injured patients. They found, however, that
these patients chose incorrect answers that were related semantically. 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.
This over-familiarity may have four causes:
impaired self monitoring — passive acceptance of inaccurate conclusions
faulty filtering — tendency to select salient associations rather than a
relevant one mnemonic association from routine
thoughts perseveration — unable to come up with
an alternate hypothesis Thus, executive dysfunction appears to
be necessary to identify one as having Fregoli's syndrome.
= 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. 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. have shown lesions in the anterior
fusiform gyrus, which is close to the face specific area, may also be
associated with Fregoli syndrome and other DMSs. 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, and the other is via the temporal-occipital ventral pathway.
Thus, lesions in either structures or disruption of delicate connections may
produce DMSs. = Abnormal P300 =
Delusional misidentification syndrome is thought to occur due to a dissociation
between identification and recognition processes. The integration of
information for further processing is referred to as working memory. The P300
is an index of WM and is 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.
Past studies have shown correlations between DMS and damages to the
right-hemispheric function, which has an array of functions. In recent years, the
P300 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 P300 component is an index of mental activity in that its amplitude increases
highly with increased stimuli. This P300 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.'s paper, psychological evidence for altered
information processing in delusional misidentification syndromes,
hypothesized that electrophysiological brain activity in the working memory and
P300 component can help identify the mechanisms of DMS. Thus, they
concentrated on P300 released during a working memory test in DMS patients.
Papageorgio et al. also found that DMS patients had a lower P300 amplitude in
the right hemisphere compared to the control group. From this result, the
researchers implied that shorter P300 amplitudes are highly correlated with
gray matter abnormalities; this finding is consistent with the DMS patients'
characteristics and the presence of gray-matter deterioration. DMS patients
were also found to have prolonged P300 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. This research is important,
because it can help determine the mechanisms of DMS, which can then help
conjure a more effective target drug and/or treatment plan for those
suffering from DMS. Treatment
Once it has been positively identified, pharmacotherapy follows. 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.
History The condition is named after the Italian
actor Leopoldo Fregoli, who was renowned for his ability to make quick changes of
appearance during his stage act. P. Courbon and G. Fail first reported
the condition in a 1927 paper. They described a 27-year-old woman living in
London who believed she was being persecuted by two actors she often saw
at the theatre. She believed these people pursued her closely, taking the
form of people she knew or met. = Delusional misidentification syndromes
and Fregoli = Delusional misidentification syndromes
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., has been replaced by a twin impostor. 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 = Delusional misidentification syndromes
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.
Current research The study of DMS currently remains
controversial, as they are often coupled with many psychological disorders.
Although there is a plethora of information on DMS, there are still many
mysteries of the physiological and anatomical details of DMS. An accurate
semiological analysis of higher visual anomalies and their corresponding
topographic sites may help elucidate the aetiology of Fregoli's and other
misidentification disorders. Popular culture
The film Anomalisa has several direct and indirect references to Fregoli
delusion. See also
Schizophrenia Cotard's Syndrome
Erotomania Psychosis
Paramnesia Prosopagnosia
Agnosia References