When the Familiar Becomes Strange: A Look at Capgras Syndrome

Capgras syndrome (CS) is a rare neuropsychiatric disorder belonging to the group of delusional misidentification syndromes. Its prevalence is under 1 percent in general psychiatric populations but higher in more specific clinical groups. The syndrome occurs in 1.3 to 4.1 percent of all psychiatric disorders and in about 3 percent of inpatients with psychotic disorders. Approximately 10 percent of individuals experiencing a first psychotic episode develop Capgras symptoms at least temporarily. The highest rates appear in schizophreniform psychoses, affecting roughly half of patients. Short-term psychotic disorders show an incidence of around 34.8 percent, while unspecified psychoses affect about 23.9 percent. Capgras symptoms also occur in severe depressive episodes with psychotic features, affecting approximately 15 percent, and in delusional disorders and classical schizophrenia, observed in about 11 percent of cases.

At the core of the syndrome lies the belief that familiar people, animals, or objects have been replaced by indistinguishable doubles. While CS was initially thought to predominantly affect women, current data indicate an even distribution across genders. It ranks among the most common forms of delusional misidentification and appears both in primary psychiatric disorders, such as schizophrenia or schizoaffective disorder, and in cases of organic brain damage.

The first detailed description dates back to 1923, when the French psychiatrist Joseph Capgras reported a case of a woman convinced that her husband and other close relatives had been replaced by doubles. She even believed a second version of herself existed. Capgras called the phenomenon “l’illusion des sosies,” or the illusion of doubles.

Initially, experts interpreted the syndrome almost exclusively as a psychiatric phenomenon and often attributed it to hysterical mechanisms, which led to the assumption that it predominantly affected women. Berson later clarified that CS should not be equated with hallucinations or memory deficits. Patients usually perceive their environment accurately but misinterpret their impressions due to a misguided belief.

From the 1980s onward, evidence increasingly showed that many patients had structural brain changes or lesions. These findings significantly shaped the understanding of the syndrome, leading to a perspective that considers both psychiatric and neurological factors.

The pathophysiological mechanisms remain incompletely understood. A widely cited explanation is Coltheart’s two-factor theory, which posits two simultaneous deficits: a lack of emotional response to familiar faces and an impaired ability to critically evaluate this anomaly. Imaging studies suggest disrupted connections between the temporal lobe, responsible for facial recognition, and limbic structures that convey emotional significance. Additional damage to the right hemisphere or frontal lobe dysfunction impairs self-monitoring and the attribution of familiarity, leading to a dissociation between identity processing and emotional relevance.

Capgras syndrome occurs in conjunction with various disorders, including dementia, Alzheimer’s disease, Parkinson’s disease, epilepsy, and vascular brain damage. Associated phenomena such as De Clérambault or Ekbom syndrome have also been described. Psychodynamic approaches attribute the delusion to a pathological splitting of internal object representations. Ambivalent or conflicting feelings toward close individuals are displaced onto an alleged double, which explains the frequently observed hostility toward the person perceived as “false.”

Diagnosis relies primarily on clinical assessment and is supported by imaging to exclude organic causes. No standardized treatment guidelines exist, but second-generation antipsychotics, particularly olanzapine, show considerable efficacy. Psychotherapeutic support, a strong therapeutic relationship, and involvement of family members help manage the syndrome and reduce the risk of aggressive behavior.

Prognosis largely depends on the underlying condition. Delusions often decrease significantly during depressive episodes or acute psychotic states, whereas they persist longer in chronic schizophrenia. Early recognition, continuous pharmacological treatment, and a stable psychosocial environment are critical for long-term outcomes.

In conclusion, despite its rarity, Capgras syndrome carries significant clinical relevance. The combination of delusional misidentification, potential aggression, and highly variable presentation demands a carefully coordinated approach. Accurate diagnosis, tailored therapy, psychotherapeutic support, and close collaboration with family form the core of effective management. Long-term professional follow-up stabilizes the course and helps patients maintain a safe and structured daily life.

Sources: 

Halder, A., Ray, S., Kumar, M., & Bhattacharya, A. K. (2024). Capgras syndrome, an interesting but rare phenomenon in Psychiatry: A case series. Telangana Journal of Psychiatry, 10(2), 183. Source

Knezevic, V., Ratkovic, D., Ivanovic Kovacevic, S., Sobot, V., Vejnovic, A. M., & Comic, M. (2024). Importance of Capgras syndrome in shared psychotic disorder: A case report. Journal of International Medical Research, 52(3), 03000605241233526. Source

Posa, F., Posa, M., Vener, V., Sclavi, F., & Ciuffreda, C. (2025). View of Capgras Syndrome and Criminal Behavior. Source

Shah, K. P., Jain, S. B., & Wadhwa, R. (2025). Capgras Syndrome. In StatPearls. StatPearls Publishing. Source