Antibody

Psychiatry

Autoimmune encephalitis

Psychosis

Encephalitis

Virus

Cerebrospinal fluid

Internal medicine

CSF pleocytosis

Autoantibody

Immunology

Pleocytosis

Medicine

Neurology

To report the neuropsychiatric features and frequency of NMDA receptor (NMDAR) and other neuronal immunoglobulin G antibodies in patients with first episode psychosis (FEP) and to assess the performance of reported warning signs and criteria for autoimmune psychosis (AP).This was a prospective observational study of patients with FEP assessed for neuropsychiatric symptoms, serum and CSF neuronal antibodies (brain immunohistochemistry, cell-based assays, live neurons), and warning signs and criteria of AP. Previous autoimmune FEP series were reviewed.One hundred five patients were included; their median age was 30 (range 14-75) years, and 44 (42%) were female. None had neuronal antibodies. Two of 105 (2%) had CSF pleocytosis, 4 of 100 (4%) had brain MRI abnormalities, and 3 of 73 (4%) EEG alterations. Thirty-four (32%) and 39 (37%) patients fulfilled 2 sets of warning signs of AP, and 21 (20%) fulfilled criteria of possible or probable AP, yet none developed AP. The cause of FEP was psychiatric in 101 (96%) and nonpsychiatric in 4 (4%). During this study, 3 patients with psychosis caused by anti-NMDAR encephalitis were transferred to our center; 2 did not meet criteria for possible AP. Of 1,159 reported patients with FEP, only 7 (1%) had CSF studies; 36 (3%) had serum NMDAR antibodies (without definite diagnosis of AP), and 4 had CSF NMDAR antibodies (3 classic anti-NMDAR encephalitis and 1 with isolated psychiatric features).NMDAR antibodies were not found in patients with FEP unless they had anti-NMDAR encephalitis. Warning signs and criteria for AP have limited utility when neurologic symptoms are absent or paraclinical tests are normal. A diagnostic algorithm for autoimmune FEP is provided.

Clinical, Neuroimmunologic, and CSF Investigations in First Episode Psychosis