Psychosurgery is a type of surgical ablation or disconnection of brain tissue with the intent to alter affective or cognitive states caused by mental illness. Psychosurgery was first introduced as a treatment for severe mental illness by Egas Moniz in 1936. At that time, no satisfactory pharmacological treatment options existed. At the height of enthusiasm, psychiatric neurosurgery was recommended for curing schizophrenia, depression, criminal behavior, and some other mental disorders. It is estimated that over 50,000 procedures were performed in the United States alone between 1936 and the mid-1950s. These operations were associated with many complications including intellectual impairment, personality change, seizures, paralysis, and death.