Anti-N-Methyl-d-Aspartate Receptor Antibody Testing in First-Episode Psychosis: Universal or Targeted Testing

Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is an immune-mediated disorder that typically presents with rapid development of neuropsychiatric symptoms. As a potentially reversible cause of psychosis, there have been calls internationally for routine serological screening for anti-NMDAR antibodies in patients presenting with first-episode psychosis (FEP). Increased serological testing has, however, exposed several limitations of universal screening and rekindled debate as to which patients should be tested. Screening criteria have been proposed for high-risk clinical features in FEP in which antineuronal antibody testing is indicated. The authors present a clinical vignette and a service audit as well as discuss the limitations of universal screening advocating instead for targeted testing for antineuronal antibodies in patients diagnosed as having FEP.