Atypical Psycho-neurological Presentation of Multiple Sclerosis: A Case Report

Background: Multiple sclerosis (MS) is a very common immune-mediated inflammatory demyelinating disorder of the central nervous system (CNS). Psychiatric and behavioral manifestations are well-documented but rarely dominate the initial sign, often adjourning diagnosis. Case Presentation: We report the case of a 32-year-old male with a history of polysubstance abuse who presented with bizarre behavior, inappropriate laughter, and tremors, primarily suggesting a psychiatric disorder. Detailed assessment, including magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) analysis, showed findings consistent with MS, in accordance with the revised McDonald criteria. Exclusion of metabolic and genetic conditions strengthened the diagnosis. The patient was initiated on fingolimod 0.5 mg daily, ensuing in significant improvement of neuropsychiatric symptoms and tremors at two-month follow-up. Conclusion: This case underlines the importance of preserving diagnostic vigilance for MS in patients presenting with atypical psychiatric or behavioral symptoms. Early recognition and timely initiation of disease-modifying therapy can improve both neurological and psychiatric outcomes.