Abbreviations: ANA, antinuclear antibodies; CSF, cerebrospinal fluid; dsDNA, double strand deoxyribonucleic acid; EEG, electroencephalography; FDG-PET, [18F]fluorodeoxyglucose positron emission tomography; FLAIR, fluid-attenuated inversion recovery; GFAP, glial fibrillary acidic protein; IgG, immunoglobulin G; MRI, magnetic resonance imaging; NfL, neurofilament light chain; NMDA-R, N-methyl-d-aspartate receptor; OCD, obsessive-compulsive disorder; R, receptor. Here, GFAP is linked to obsessive-compulsive disorder.