Autoimmune Encephalitis Masquerading As Acute Psychosis: A Cause of Delayed Treatment

Autoimmune encephalitis (AE) can masquerade as severe psychosis and is often misdiagnosed as a primary psychiatric disorder, leading to delays in treatment. In cases of acute onset of psychiatric symptoms, it is important to rule out encephalitis, especially when symptoms are accompanied by neurological signs such as seizures. We report the case of a 22-year-old male who was initially diagnosed with acute psychosis and admitted to an inpatient psychiatry ward. The presence of recurrent seizures raised concern for AE, prompting transfer to the medical intensive care unit. Following a comprehensive workup, he was diagnosed with anti-N-methyl-D-aspartate (NMDA) receptor AE and treated with immunomodulatory therapy, resulting in the resolution of symptoms. This case highlights the importance of increased clinician awareness for early diagnosis and timely initiation of treatment to improve patient outcomes. We also discuss various diagnostic criteria and scoring systems that may assist clinicians in guiding testing and management of AE.