This paper reports a patient with Moyamoya disease who developed a psychotic disorder following a stroke. A 47-year-old female with Moyamoya disease without a psychiatric history experienced persecutory delusion and auditory hallucinations after eight months of intracranial hemorrhage in the right temporal lobe. The adult was managed with low-dose antipsychotics, risperidone. A brief Psychiatric Rating Scale was performed weekly after hospitalization, and psychotic symptoms eventually were under control after three weeks following the initiation of psychotropic medication. This case suggests that low-dose antipsychotics would be effective in patients with psychosis newly developed from a stroke secondary to Moyamoya disease.