Delusional misidentification syndromes following acquired brain injury: A scoping review of clinical manifestations, neuroanatomical bases, and treatment approaches

Objective: Delusional misidentification syndromes (DMS) are rare psychopathological phenomena characterized by fixed false beliefs about the identity of familiar others (e.g. Capgras, Fregoli) or the self (e.g. Cotard’s) which can present significant clinical challenges, including risks to patient safety and distress for family members. Although most commonly described in psychiatric or neurodegenerative contexts, DMS may also occur following acquired brain injury (ABI), providing a valuable window into the neurocognitive mechanisms underlying familiarity processing, self/other representation, and belief evaluation, as well as informing clinical management of these complex presentations. This review aimed to scope the available literature on the development of DMS following ABI. Method: A scoping review was conducted across PsycINFO, CINAHL, and MEDLINE from inception to February 2026. From 173 initial records, 34 studies were eventually included. Results: Most studies were single-case reports, with only one observational cohort. Eighteen reported Capgras as the primary presentation following ABI, while four reported Fregoli, and six Cotard’s. Additional studies described mixed, variable, or longitudinal presentations. Neuroanatomical findings most consistently implicated right-hemisphere fronto–temporo–parietal networks with prominent frontal involvement. Treatments were inconsistently reported and outcomes varied from complete remission to chronic persistence. Conclusions: DMS following ABI are rare but clinically significant phenomena, with Capgras syndrome representing the most frequent presentation. Converging evidence supports a network-level involvement of right-hemisphere fronto-temporo-insular areas underpinning familiarity processing, self-representation, and belief evaluation. Further exploration of DMS following ABI is warranted to inform diagnosis, risk assessment, clinical management, interventions, and communication with affected individuals.