Neural antibodies in first-episode psychosis patients with warning signs for autoimmune encephalitis
Denis Pavăl 1, 2*, Nicoleta Gherghel-Pavăl 2, Octavia Oana Căpățînă 1, 2, Adina Stan 3, Lajos Raduly 4, Liviuța Budișan 4, Ioana Valentina Micluția 1
1Department of Psychiatry, “Iuliu Hațieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania, 2Romanian Association for Autoimmune Encephalitis, 400193 Cluj-Napoca, Romania, 3Department of Neurology, “Iuliu Hațieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania, 4Research Center for Functional Genomics, Biomedicine and Translational Medicine, “Iuliu Hațieganu” University of Medicine and Pharmacy, 400337 Cluj-Napoca, Romania
Received: January 1, 2024; Revised: February 28, 2024; Accepted: March 20, 2024; Published online: March 20, 2024.
© The Korean College of Neuropsychopharmacology. All rights reserved.

Objective: Autoimmune encephalitis (AE) remains an essential differential diagnosis in patients with first-episode psychosis (FEP). In this study, we aimed to assess to prevalence of AE in a cohort of FEP patients.
Methods: We used a phenotype-driven algorithm to detect AE in patients with FEP. Initially, we screened patients for warning signs with a low or high pre-test probability for AE, defined as “yellow” and “red flags”, respectively. In the next step, patients with red flags underwent CSF analysis (including neural antibodies), while patients with yellow flags underwent tests for serum neural antibodies, EEG, and brain MRI.
Results: We screened 78 patients with FEP and found that eight (10.3%) had at least one warning sign for AE: four (5.13%) patients had at least one red flag, while four (5.13%) had only yellow flags. Among these, two patients (2.56%) had anti-NMDAR encephalitis, while the remaining six (7.69%) received a primary psychiatric disorder diagnosis.
Conclusion: Our study highlights the importance of considering AE in the differential diagnosis of FEP.
Keywords: autoimmune encephalitis, autoimmune psychosis, first-episode psychosis, neural antibodies, warning signs, algorithm