Abstract
SOX1 antibody is an autoimmune antibody, usually associated with Lambert-Eaton myasthenic syndrome, paraneoplastic conditions, and encephalitis. This antibody has also been found among psychiatric patients. However, the role of SOX1 antibody in serotonin syndrome has not yet been defined, as a literature search yielded no results. Therefore, the treatment as such has unknown clinical significance. In this case study, we report a patient with SOX1 antibodies and altered mental status out of proportion to serotonin syndrome whose symptoms improved with simultaneous treatment of both conditions.