There is retrospective evidence of a correlation between psychosis in multiple sclerosis (MS) however comorbidity of Psychosis in MS patients is a less frequent condition and the treatment of this condition seems to be hard and complex.

32 years old, male patient with MS had psychotic symptoms simultaneously with exacerbations of MS symptoms for three times in three years.

The first psychiatric episode was one year after he had the diagnosis of MS due to episodes of difficulty in walking and determination of demyelination plagues by MRI. Irritability, delusions of jealousness and persecutions, agitation, drug refusal were occurred simultaneously with the exacerbated symptoms of MS as right sided hemiparesia. He had been hospitalized and treated with olanzapine and high dose of corticosteroids. After this first episode he had two simultaneous episodes of psychosis with similar symptoms to previous one and exacerbations of MS with more severe symptoms as additional urinary incontinence. He was treated with olanzapine and corticosteroids in all episodes. The psychotic symptoms were remitted and the symptoms of MS were improved partially.

Psychosis is not a prominent feature of MS, occurring in 5% of cases. The relationship between lesions of the central nervous system and psychiatric illness has not been established yet. Some reports have implicated the contribution of acute demyelination to psychosis. In this case the simultaneous episodes of MS symptoms and psychosis suggest a common etiology. Prospective studies are required both about the common etiology and treatment.