A Case Report of Anti-N-Methyl-D-Aspartate Receptor (NMDAR) Encephalitis.

Anti-N-methyl-D-aspartate (NMDA) receptor NMDAR) encephalitis is a relatively recent condition, classified as an immune-mediated disorder characterized by a complex neuropsychiatric syndrome and the presence of anti-GluN1 subunit antibodies against the NMDA receptor in cerebrospinal fluid (CSF). Although it is a rare disease, studies have identified it as one of the most common causes of autoimmune encephalitis. The pathophysiology of this condition is not yet fully understood, especially regarding its association with ovarian teratomas and other neoplasms. We present the case of a 30-year-old woman, previously healthy and independent, who developed a sudden onset of psychosis, marked emotional lability, disorganized speech, and agitation. Subsequently, she experienced severe sleep deprivation accompanied by grandiose delusions and auditory hallucinations. Due to the fluctuating nature of her symptoms and their progressive worsening, the patient required prolonged hospitalization, including admissions to intermediate and intensive care units, and underwent extensive diagnostic testing before a definitive diagnosis was made. Early diagnosis of anti-NMDAR encephalitis is crucial, as prompt and appropriate treatment can significantly reduce long-term sequelae and the risk of recurrence. This case underscores the importance of considering anti-NMDAR encephalitis in the differential diagnosis of new-onset psychiatric disorders, especially those resembling schizophrenia.