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The Delusion of Doubles: What if Your Loved Ones Become a Lie

Updated: Jul 9, 2025

Written By: Roan Aly

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We all have loved ones; it’s the essence of human nature – socializing, connecting, forming bonds. But what if, on a completely ordinary day, amidst the confusion and stress of your daily life, a doppelganger replaces your loved one and aims to spy on you. And what if, then, as you report this newfound information to everybody you know, with quite not enough evidence to prove it, you are labelled insane? What if, despite your persistence in the veracity of your sanity, the brume of madness has truly infected the recesses of your mind? This brume, the Delusion of Doubles, is the most prevalent delusional misidentification syndrome, and has caused violence, injuries, and death.


Capgras Syndrome, going by a number of differing names such as the Delusion of Doubles, Imposter Syndrome, and Capgras Delusion, encompasses the main notion of the psychiatric disease, in which an individual persistently believes that a loved one, either a person or a group of people, has been replaced by an imposter. Those with this disease typically possess the delusional conviction that the “imposter” who has suddenly entered their life harbors ill, persecutory intent towards them or another loved one. This syndrome is sometimes mistaken for the Fregoli delusion, in which an individual holds the delusional belief that different people are all a single person who changes their appearance and is in disguise. Capgras syndrome is the most prevalent disease in the vast array of delusional misidentification syndromes (DMS). 

The most common loved one that the afflicted patient would accuse is their own spouse, in which they delusionally believe that an imposter of the same sex has replaced their spouse, and ergo is attempting to spy on or harm them or somebody close to them. The accused imposter can range from a parent or spouse to even one’s own child or siblings. In rare cases, however, one may even accuse themself of being the imposter, known as “reverse Capgras syndrome”.


A concomitant symptom that many afflicted with Capgras delusion experience is the increased threat of violent behaviours due to paranoia, often a result of the persecutory intent which it is believed that the accused harbors. The risk of violence and homicide is much higher in male patients compared to female patients with the Capgras delusion, despite the condition being more common in the latter. Moreover, patients often demonstrated social withdrawal and self-isolation prior to violent acts. Oftentimes, the victims were found to be family members or coresidents of the patient, which is consistent with the evidence that those most familiar to patients are more likely to be misidentified. 


Eight cases of Capgras delusion were examined in a 1989 case series, and the following violent behaviors were found: shot and killed father, pointed knife at mother, held knife to mother’s throat, punched parents, threatened to stab husband with scissors, non-specifically threatened physical harm to family, injured mother with axe, and threatened to stab son with knife and burn him. Seven of the 8 patients were coresidents with the misidentified persons, and 5 of the 8 patients were averse to treatment attempts. The study suggested that the chronicity and content of the delusion seemed to increase the risk of violent behaviours. The case posited that the patient would try to keep their agitation hidden, careful lest any trace should be left exposed. Despite the appearance of stability, patients were likely to react violently to minute changes.


The provenance of this condition is rather well known, despite very little being known about the disease itself. A French psychiatrist, Joseph Capgras, is the first known man to have described this delusion. He and Jean Reboul-Lachauxx coauthored a paper on a paranoid 53-year-old woman who, according to the paper, “transformed everyone in her entourage, even those closest to her, such as her husband and daughter, into various and numerous doubles.” She held the delusion of being famous, wealthy, and of royal lineage. Despite the fact that 3 of her 4 children had passed away, she was firm on her belief that they were abducted, and that her only surviving child was replaced by an imposter who donned a similar appearance. 


Capgras delusion, while de trop, is not extremely pervasive, as studies have found that the morbidity rates of this delusion affect 0.12% of the population in general, and 1.3% as a comorbidity for primary diagnoses of other diseases, such as schizophrenia. Other primary diagnoses that can entail Capgras syndrome include schizoaffective disorder, Alzheimer disease (AD), Lewy body dementia, epilepsy, cerebrovascular accident (CVA), pituitary tumours, and advanced Parkinson disease (PD). It was also found that women experience Capgras delusion more often than men, with three women having the syndrome for every two men.


There are several theories on the causes of Capgras syndrome. It may occur after structural changes in the brain, such as atrophy, lesions, dysfunction, or injury. Capgras syndrome has been linked to brain damage in the bifrontal, right limbic, and temporal regions of the mind. Very little else is known about the disease – medical professionals struggle identify how it develops, but they believe that both the dysfunction of facial processing neural networks as well as hypothesis-appraisal networks result in the skewed facial recognition of the misidentified loved one. This belief, however, makes way for a concerning possibility: there may be genetic factors that influence both the occurrence and content of these delusions. This cause is not set in stone, however, as another scientific review of 255 published cases of Capgras syndrome shows that researchers find it challenging to pinpoint the exact cause, which varies among cases. Furthermore, no cure has been discovered for this delusion. A 2014 study showed that 73% of Capgras syndrome cases had comorbid diagnosis of schizophrenia, 26.4% had dementia and 16.7% had mood disorders. It has been found that treating this condition’s comorbidities, if any are present or identified, can ease its symptoms. 


Of the numerous cases of Capgras syndrome, an example includes a 24-year-old male who had received many mental health diagnoses in the past, but no history of any brain trauma. The patient was admitted into a hospital after confessing to self-harm attempts and criminal activity. He stated: “I feel everything is unreal. I feel suicidal and guilt”, and plotted to either walk onto an active road or shoot himself in the head due to disturbing thoughts and memories. The main piece of evidence that allowed the medical professionals to diagnose him with Capgras syndrome was due to his belief that his mother was not real. He claimed: “Last year my sister told me it was not 2016, but it was 2022. She told me that I have hurt my mother with a padlock—that you could no longer identify her face. I don’t remember having done this. I have lived with her since that time, so I don’t think it’s really [my mother].” He firmly held onto the belief that his mother was replaced by government officials who were sent to spy on him and elicit confessions for his inappropriate behaviour while in the military. Younger patients with the Capgras delusion have been found more likely to have purely psychiatric comorbidities—such as schizophrenia, substance-induced psychosis, or schizoaffective disorder—as opposed to underlying medical conditions. In the case of the 24-year-old male, the Capgras delusion was thought to be due to a disorder in the schizophrenia spectrum, specifically schizophreniform disorder.


Capgras syndrome, a delusional misidentification syndrome initially discovered by French psychiatrist Joseph Capgras, describes the delusion in which an afflicted patient believes that a loved one is an imposter who harbors ill intent towards them. The psychological condition is most common in patients with previous mental health diagnoses, and is more likely to occur in women. The exact cause is unknown however, due to the belief that the misidentified person aims to harm them, the patient is likely to display violent behaviours towards them, despite appearing mentally stable. There is no cure for the condition, however therapy and targeting comorbidities may assist in lessening the symptoms. The cause of the illness is not known, and while many theories have been made, the development of the delusion seems to differ between patients. The delusion of doubles has the potential to turn your loved ones into a lie, or turn you into a lie in the reality of a loved one. Mysterious and seemingly incurable, the delusion only spreads.


References :

Gotter, A. (2017, May). What Is Capgras Syndrome? Healthline; Healthline Media. https://www.healthline.com/health/capgras-syndrome

Chhaya, T. (2017). She’s Not My Mother: A 24-Year-Old Man With Capgras Delusion. Federal Practitioner : For the Health Care Professionals of the VA, DoD, and PHS, 34(12), 38–41. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6370465/

Shah, K. P., Jain, S. B., & Wadhwa, R. (2023, May 29). Capgras Syndrome. Nih.gov; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK570557/

Ellis, H. D., & Lewis, M. B. (2001). Capgras delusion: a window on face recognition. Trends in Cognitive Sciences, 5(4), 149–156. https://doi.org/10.1016/s1364-6613(00)01620-x


 
 
 

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