Rituximab Was Effective for Treatment of Anti- N -Methyl- d -Aspartate Receptor Encephalitis in Early Adolescence in Initially Suspected Dissociative Disorder

Objectives Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is an increasingly recognized etiology of psychiatric symptoms. Because patients with anti-NMDAR encephalitis frequently show aggression, mania, hallucination, depression, or delusion, they are initially diagnosed with schizophrenia or mood disorders. There is only 1 case report of an initially diagnosed dissociative disorder. Methods We obtained consent for the presentation and have not identified individuals for ethical reasons. Results We first report an adolescent female patient with anti-NMDAR encephalitis who was initially suspected of having dissociative disorder but was responsive to immunotherapies including rituximab. In this case, her symptoms and electroencephalogram findings were proportional to the antibody titer in the cerebrospinal fluid. Conclusions It is important to consider the possibility of autoimmune encephalitis and immunotherapy including rituximab in cases of not only acute psychosis but also dissociation.