Fregoli syndrome: the delusional belief that a loved one is disguised as other people

Remember that old post about Capgras syndrome ? There's an equally fascinating, and somewhat inverse, counterpart: Fregoli syndrome.

Both disorders fall under the category of delusions of identification with persons (DIP). In Capgras syndrome, also known as the doppelganger delusion , the patient is convinced that a loved one has been replaced by an imposter with a completely identical appearance. Conversely, in Fregoli syndrome, the patient believes that a familiar person, sometimes several, constantly changes their appearance.

Most often, he wrongly identifies several people around him as actually being a single malevolent figure, disguised or transformed. This figure is perceived as omnipresent, following the patient around in different disguises.

This is a delusional belief that a known individual adopts appearances that are completely unrelated to their usual appearance. In other words, people with no apparent physical connection are interpreted as manifestations of a single, multifaceted persecutor.

There may be several variants of this syndrome, depending on the combinations imagined by the patient.

First scenario: a single real person, for example a casual acquaintance, is mistaken for a known person.

For example, a 68-year-old woman with schizophrenia who had suffered a stroke mistook another hospital patient, a virtual stranger, for her husband, who had died four years earlier. Yet there was no physical resemblance between the two men. She offered no explanation for her husband's alleged presence at the facility.

A second case involved a 38-year-old woman who believed that a stranger she saw on the banks of the Thames in London was actually an American taxi driver she knew, but disguised to avoid recognition. Two weeks earlier, she had assaulted the same driver in Los Angeles before traveling to the UK. She also believed that a Russian musician living in the US, whom she also knew, had hired the driver to kill her. According to her, the driver was now in the UK and had undergone cosmetic surgery to alter his appearance.

Another case is particularly notable because of the coexistence of Fregoli syndrome and Capgras syndrome. It concerns a 62-year-old woman with paranoid schizophrenia who developed Fregoli delusions while hospitalized. She claimed that her doctor, the only real person, was in fact her husband… wearing a woman's mask. There was no evidence to suggest a physical resemblance between the two. Moreover, her husband had died two years earlier.

Her hospitalization was initially motivated by other delusions, in particular the belief that her 20-year-old son had been replaced by an imposter: a delusion typical of Capgras syndrome. However, it is not certain whether Fregoli and Capgras delusions were present simultaneously in this patient.

Among other possible combinations, it happens that several real people, for example strangers encountered at different times, are all wrongly identified as a single known person, who would constantly change physical appearance.

In 1999, Irish psychiatrists reported the case of a 44-year-old man with chronic schizophrenia who presented with a complex set of delusions, several of which concerned his environment. Although the town where he lived resembled a locality in Northern Ireland (which it actually was), he was convinced that it was "Middle-earth," the fictional universe of Tolkien's The Lord of the Rings (1954). His Fregoli syndrome fitted into this delusional construct: he believed he was being followed and persecuted by Saruman, one of the characters in the novel, who alternately took the form of different people he encountered.

Finally, another configuration occurs when two or more real people are each misidentified as separate known people. In other words, each real person is mistakenly associated with a different familiar person. It also happens that several real individuals are all mistaken for a single known person.

Some patients even present mixed forms, combining different configurations. A representative example of this configuration was published in 2004 by American psychiatrists in the Journal of Neuropsychiatry & Clinical Neurosciences . It concerns a 30-year-old woman who mistakenly identified several strangers as several known people, each real person being associated with a single familiar figure. Thus, she took another patient in the unit for her boyfriend, a nurse for her mother, and the social worker for her sister. In no case was there any physical resemblance between the real individuals and the identified relatives. Yet, the patient was convinced that her mother, sister, and partner had been physically transformed and that they now presented themselves as strangers.

Another clinical case illustrating mixed forms of Fregoli syndrome was described in 1999 in the journal Cortex . New York neuropsychologists reported the case of a 61-year-old man who developed Fregoli syndrome following a head trauma after falling down a staircase leading to his basement. His delusion of identifying people included no fewer than thirteen mistakes divided into four distinct categories: five errors concerned family members, four coworkers, three former acquaintances, and one... himself.

During his hospitalization in rehabilitation, while discussing his stay with staff, this sixty-year-old man approached a severely disabled young man in a wheelchair, whom he had never met before, and claimed that he was his youngest son. He maintained this statement despite obvious physical differences between this patient and his real son. Even when staff pointed out these discrepancies, the patient persisted in his error, convinced that he had recognized his child.

He made numerous confusions involving his loved ones. He notably thought he saw his eldest son on television, boxing in a report, claiming that the latter was probably unaware he was being filmed. He also wrongly identified a nurse's assistant as his daughter-in-law, and then another young patient as his second daughter-in-law.

The patient said he saw his younger son at the hospital, disguised as a girl in order to join a group of female patients. He said the son took advantage of a vacant spot in the "girls' group" and slipped in under a false identity.

Finally, this same patient claimed that a former coworker was in the same hospital as him, in a wheelchair. He was convinced that this man was using a false name, in fact the real name of another patient in the ward. Furthermore, he wrongly identified another female patient at the hospital as a former client with whom he had worked.

Another example, reported in 1987 by British psychiatrists in the Journal of Nervous & Mental Disease , illustrates this pattern in which real people are misidentified as two separate known people.

The case concerns a 66-year-old widow who believed she recognized her cousin and his partner as various strangers she encountered in her environment. The patient went into very detailed descriptions, mentioning the wigs, false beards, makeup, and other devices the couple allegedly used to disguise themselves. She claimed, for example, that her cousin's partner sometimes pretended to be a man, and that her cousin could pretend to be an old man.

Despite obvious physical differences between the real people and the famous people they were supposed to impersonate, the patient remained convinced of their identity. Convinced that she was being followed by this multifaceted couple, whom she considered dangerous, she regularly altered her routes to escape them. She believed they knew that she was the only one in the family aware of their relationship and their criminal activities.

The term "Fregoli syndrome" was introduced in 1927 by Paul Courbon and Gabriel Fail, in homage to Leopoldo Fregoli (1867-1936), an Italian actor and drag artist, famous for his extraordinary ability to quickly change his costume and appearance on stage .

These two doctors described the case of a 27-year-old young woman, a domestic worker with a passion for theater. She believed that two famous Parisian actresses of the time, Sarah Bernhardt and Robine, were persecuting her by incarnating themselves in the bodies of other people she met: doctors, nurses, strangers, or friends. For example, this patient believed that Sarah Bernhardt, whom she had seen on stage one Sunday evening, was exactly the same person she had encountered in the street the following Monday, disguised as a stranger.

In her delirium, Robine or Sarah Bernhardt pursued her "to take away her thoughts, prevent her from making this or that gesture, force her to carry out others, give orders and desires..." These actresses took possession of the body of others without changing its outward appearance, imposing their will on the patient, a phenomenon that Courbon and Fail called "fregolification". The patient explained that the actress Robine "fregolified" her doctor by transforming him sometimes into her deceased father, sometimes into a doctor from her childhood.

For her, the women she met in the street or the nurses at the hospital, even without any visible common traits with Sarah Bernhardt or Robine, were in reality these disguised actresses, come to control her and impose actions on her against her will. Thus, the nurses at the hospital prevented her from "thinking and acting" . She also said: "Robine sends me impulses, she imposes actions on me, she forces me, for example, to masturbate at certain times, and she does all this under the most diverse disguises."

The particularity of delusions of identification of persons (DIP) is that they can occur both in psychiatric pathologies, a priori non-organic or without clearly identifiable cerebral lesions to date, as well as in neurological conditions, associated with objectifiable cerebral lesions.

Several studies have compared the neuropsychiatric characteristics of patients with Fregoli syndrome, depending on whether it appears as part of a primary psychiatric disorder or is secondary to neurological damage.

In 2023, London neuropsychiatrists published the first meta-analysis focusing exclusively on cases of Fregoli syndrome. This review, the most comprehensive and recent in the medical literature devoted to this disorder, brought together 83 articles describing a total of 119 cases reported in the English-language literature between 1927 and the end of 2020, representing a publication rate of just 1.3 cases per year.

A total of 89 patients meeting strict criteria for Fregoli syndrome were included in the analysis. Among them, 55 patients (62%) presented with this syndrome in the context of a primary psychiatric disorder, i.e., not induced by substance abuse or an underlying medical condition.

The majority of these patients suffered from schizophrenia (58%), more rarely from bipolar disorder, psychotic depression, schizoaffective disorder (mixed form combining symptoms of schizophrenia and mood disorders) or obsessive compulsive disorder (OCD).

Approximately 38% of patients developed Fregoli syndrome in the context of psychosis secondary to a neurological pathology, most often a stroke or head trauma, sometimes in the context of a neurodegenerative disease or epilepsy.

This high proportion of secondary forms leads the authors of the meta-analysis to recommend that "clinicians prioritize a neurological cause rather than a primary psychiatric cause in any patient with Fregoli syndrome, and therefore request relevant brain imaging tests, such as an MRI."

Most patients with secondary Fregoli syndrome had an identified neurological pathology (stroke, head injury, neurodegenerative disease, epilepsy, etc.). These patients were significantly older than those with Fregoli syndrome associated with primary psychosis: on average 60 years versus 33 years.

Among patients with secondary psychosis, nearly three-quarters had lesions located in the right hemisphere, and more than half showed frontal lobe abnormalities. Similarly, a Japanese study, published in 2020 in the journal Brain and Behavior , highlighted several brain areas whose lesions are statistically associated with Fregoli syndrome occurring after a stroke, compared them to those observed in a control group. These regions include the insula, inferior frontal lobe, anterior temporal lobe, and the subcortical limbic system, all located in the right hemisphere.

In contrast, very few patients with primary psychosis have benefited from brain MRI. In any case, additional studies in structural and functional neuroimaging remain necessary to better characterize the location of brain abnormalities, as well as the neural circuits possibly involved in Fregoli syndrome.

In 2014, Italian neurologists and psychiatrists reported the case of a 61-year-old woman who developed Fregoli syndrome after acute pneumonia associated with a urinary tract infection. The scientific literature mentions only one other case linked to an infection: typhoid fever.

In 2016, a Spanish team described the case of a 77-year-old woman with vascular dementia who developed Fregoli syndrome during her hemodialysis sessions. She was convinced that several people in the clinic were actually her son's neighbor, a man she knew but rarely saw. According to her, this man stalked her and only appeared during dialysis sessions, where he taunted her. She also believed that the clinic staff were aware but refused to intervene. One month after the onset of symptoms, she changed hemodialysis centers, with no improvement. The reason why this delirium intensified during hemodialysis remains unknown, but in the context of dementia, fluctuations in cognitive abilities are common.

In rare cases, Fregoli syndrome is accompanied by erotomania, a condition in which patients come to delusionally believe that someone is in love with them. For example, one patient believed that another patient, using a false name, was her ex-boyfriend and that they were still deeply in love.

In another case, a patient believed she was the girlfriend of Erik Estrada , an American actor, with whom she communicated telepathically across the Atlantic. She was convinced that he regularly came to her hometown, disguised as someone she knew or as her current boyfriend, whom she could distinguish thanks to an old scar on his face. She was convinced that Erik Estrada was in love with her and planned to marry her one day.

In cognitive neuropsychiatry, several hypotheses have been put forward to explain delusions of person identification (DPI), including Fregoli syndrome. These explanations are based on a model of face recognition, which differs depending on the location of the responsible abnormality.

In 1990, two neuropsychologists specializing in facial recognition suggested that the delusion of Fregoli syndrome stems from a dysfunction of the "person identity nodes " (PINs) and the cognitive system associated with them. These nodes are areas of the brain responsible for associating a perceived face with the identity of a known person, by integrating various information (face, name, context, memories, emotions).

According to this theory, when a person thinks intensely about someone, the corresponding PINs can be abnormally activated. This overactivation then leads to false recognition: the patient believes they have identified this person even though they are not actually present.

A classic example is that of the patient described in 1927 by Courbon and Fail, who was so passionate about the theater that she deprived herself of food to attend performances. Her mind constantly mobilized mental images of her favorite actresses, Sarah Bernhardt and Robine. Thus, when a stranger made a gesture resembling that of Sarah Bernhardt (such as waving her arms), the patient believed she recognized her in this disguise.

In summary, this model explains that Fregoli syndrome would be due to cognitive confusion where the brain wrongly associates different people with a single, familiar identity, due to excessive and inappropriate activation of the "identity nodes".

Other cognitive models have been proposed to explain this syndrome. In 1998, Ramachandran and Blakeslee (San Diego, California) hypothesized that patients with this delusion have abnormally hyperactive connections between facial recognition systems and the limbic system, particularly the amygdala, which plays a key role in emotion management. In other words, unlike Capgras syndrome, where there is an absence or reduction of the emotional response when recognizing a face, in Fregoli syndrome, the emotional response would be excessive or inappropriate.

Later, in 2005, William Hirstein, a researcher from Elmhurst, Illinois, proposed that delusions of identity in people result from a deficit in the ability to "read" or emotionally understand others. This deficit causes a discrepancy between the internal representation of a person (i.e., their personality, beliefs, emotions) and their external representation, i.e., their physical appearance. In short, the brain struggles to associate what it "feels" about the other with what it sees, leading to confusion between real and perceived identity.

When Fregoli syndrome is secondary to another condition, treatment focuses primarily on addressing the underlying psychiatric or neurological disorder. Antipsychotics are often used as first-line treatment, but other approaches such as electroconvulsive therapy (ECT), antiepileptic drugs, or lithium have also been used.

Furthermore, published data remain very limited concerning the effectiveness of atypical neuroleptics (modern antipsychotics, notably used for schizophrenia) or antidepressants in the treatment of delusions of person identification.

In very rare cases, Capgras syndrome (doppelganger delusion) and Fregoli delusion can occur in the same person, suggesting a common basis for these disorders.

In 1992, Californian psychiatrists reported the case of a 41-year-old man who initially presented with Capgras syndrome, before developing a Fregoli delusion. Initially, he believed his wife was no longer his wife, then he developed a delusion in which his deceased mother looked like his wife. Quite a program...