A sense of being inserted by the original self: A distinctive manifestation of delusional misidentification of the self, a case report.

Background: Delusional misidentification of the self is a rare psychotic symptom in which individuals misidentify themselves. These symptoms are sometimes accompanied by psychotic renaming, reflecting profound psychological changes in the self. To date, such symptoms have not been fully understood through the lens of the minimal self, especially with respect to the sense of agency (SoA). Case Presentation: We report the case of a patient with schizophrenia who exhibited delusional misidentification of the self. He denied his original name, consistently referred to himself by a female name, and stated that he was a woman. He additionally reported various body alterations, including the belief that he had a female body. These psychological and bodily changes in the self are compatible with reverse intermetamorphosis, a specific subtype of delusional misidentification of the self. He also exhibited Capgras delusion involving his parents. Furthermore, as a distinctive feature, he described a sense of being inserted into and being controlled by an external agent who, strikingly, bore his original name. Conclusion: These symptoms suggest that a pathophysiology underlying a marked disruption of SoA, accompanied by delusional compensatory mechanisms, may contribute to profound psychological changes in the self. Bodily alterations and a comorbid Capgras delusion may represent additional key pathophysiological features that further disturb the sense of self. A delusional agent may come to significantly dominate the original SoA, and paradoxically, this dominance may generate a unified sense of self centered on the delusional agent.