Psychosurgery, also called neurosurgery for mental disorder, is the neurosurgical treatment of mental disorder. Psychosurgery has always been a controversial medical field. The modern history of psychosurgery begins in the 1880s under the Swiss psychiatrist Gottlieb Burckhardt. Psychosurgery is a field of surgery which consists of stereotactic operations on the brain aimed at altering abnormal physiology by severing certain connections between the frontal lobe and the rest of the brain, including the cortex, the nuclei or other brain pathways, which may appear to function normally or abnormally, in order to reduce mental and/or physical suffering in otherwise untreatable patients. While it was introduced by Moniz in 1936, its popularity and applications boomed for a brief period, only to collapse like a deflated balloon within a few decades. The primary cause of this wane in the practice of psychotherapy was the inappropriate and nonselective use of the operation for all kinds of indications, without regard to the evidence for a good outcome. The lack of accurate diagnostic criteria for many psychiatric disorders, coupled with poor recording and regulation, led to the rise of immense controversy surrounding this field. 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.