Mood disorder as the presenting manifestation of demyelination

Objective: To report an unusual presenting manifestation of multiple sclerosis in a teenager. Case Report: We report the case of a 16-year-old male who was diagnosed with schizoaffective disorder a year prior to his neurological consultation. Neurological examination showed evidence of mild lower extremity spasticity with ataxia and dysarthria. Imaging revealed lesions suggestive of multiple sclerosis. Conclusion: An organic basis for psychiatric disorders is often overlooked. Children presenting with symptoms suggestive of a mood disorder, decline in cognition or psychosis deserve a detailed neurological examination and appropriate imaging if indicated, before starting them on antidepressant or neuroleptic medication.