We reported a 19-year-old woman with multiple sclerosis (MS) with recurrent episodes of psychiatric symptoms at the age of 10 and 19, as the first and 11th relapse, respectively. Her first episode of MS resembled acute encephalitis at the age of 9 and she relapsed 12 times. The psychiatric symptoms were not mood disorders but altered states of consciousness, such as the delirous state. She was treated with high doses of intravenous methylpredonisolone and her symptoms were almost resolved, but her anxiety neurosis remained. Her MRI showed demyelination in the white matter of the frontal lobe and the hippocampus, which suggested that psychiatric symptoms of MS would be related to the frontal lobe lesion.