Supplementary information for: Clinical, neuroimmunologic, and CSF investigations in first episode psychosis

Objectives: To report the neuropsychiatric features and frequency of N-methyl-d-aspartate receptor (NMDAR) and other neuronal IgG antibodies in patients with first episode psychosis (FEP), and assess the performance of reported warning signs and criteria for autoimmune psychosis (AP).

Methods: 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.

Findings: 105 patients were included; median age 30 years (range 14-75), 44 (42%) female. None had neuronal antibodies. Two/105 (2%) had CSF pleocytosis, 4/100 (4%) brain MRI abnormalities, and 3/73 (4%) EEG alterations. Thirty-four (32%) and 39 (37%) patients fulfilled two 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...