Abstract
Cushing syndrome is a rare disease that rarely presents as acute psychosis. In this case, the patient presented with acute psychosis and agitation as the first manifestations of the disease which led to the admission of the patient to a psychiatry hospital for one month, as it was difficult to restrain her sufficiently for performing appropriate diagnostic tests due to disturbing behavior. She responded well to treatment with olanzapine and lorazepam to treat the patient's agitation, and successfully complete her evaluation. Thereafter, she was diagnosed with a pituitary tumor and underwent pituitary lesion resection via a microscopic transsphenoidal as needed. Two months after surgery, her cortisol levels returned to baseline, and she became calmer and decreased the tensity of her psychosis; however, it was only five months after surgery that her psychotic symptoms and disturbed behavior ceased.