Lobotomy.

There are nerves that connect the frontal lobes to the rest of the brain. The idea behind psychosurgery, , was that these nerves were somehow malformed or damaged, and if they were severed they might regenerate into new, healthy connections. Contrary to popular conception, the operation was not used only on psychiatric patients. Many people were lobotomized for “intractable pain”, such as chronic, severe backaches or agonizing headaches.
The three common versions of psychosurgery were prefrontal leucotomy, prefrontal lobotomy, and transorbital lobotomy.
A leucotomy (from the Greek λευκός – leukos: "clear/white" and tome) basically involved drilling holes in the skull in order to access the brain. Once visible, the surgeon would sever the nerves using a pencil-sized tool called a leucotome. It had a slide mechanism on the side that would deploy a wire loop or loops from the tip. The idea was to be able to slide the “pencil” into the pre-drilled holes in the top of skull, into the brain, then use the slide to make the loop(s) come out. The surgeon could sever the nerves by removing “cores” of brain tissue, slide the loop back in, and the operation was complete.
A lobotomy (Greek: λοβός – lobos: "lobe (of brain)"; τομή – tome: "cut/slice") also utilized drilled holes, but in the upper forehead instead of the top of the skull. It was also different in that the surgeon used a blade to cut the brain instead of a leucotome.
The infamous transorbital lobotomy was a “blind” operation in that the surgeon did not know for certain if he had severed the nerves or not. A sharp, ice-pick like object would be inserted through the eye socket between the upper lid and eye. When the doctor thought he was at about the right spot, he would hit the end of the instrument with a hammer.

Gottlieb Burckhardt, a psychiatrist with little experience of surgery, made one of the first forays into the field of psychosurgery when he operated on six patients in a private psychiatric hospital in Switzerland. Their diagnoses were, variously, one of chronic mania, one of primary dementia and four of original paranoia and, according to Burckhardt's case notes, they exhibited serious psychiatric symptoms such as auditory hallucinations, paranoid delusions, aggression, excitement and violence. He operated on the frontal, temporal, and tempoparietal lobes of these patients. The results were not overly encouraging as one patient died five days after the operation after experiencing epileptic convulsions, one improved but later committed suicide, another two showed no change, and the last two patients became "quieter".

The next stage in the development of the procedure was provided by neurologist António Egas Moniz. He devised the surgery called prefrontal leukotomy which was carried out under his direction by the neurosurgeon Pedro Almeida Lima. He was also responsible for coining the term psychosurgery.The procedure involved drilling holes in the patient's head and destroying tissue in the frontal lobes by injecting alcohol. He later changed technique, using a surgical instrument called a leucotome that cut brain tissue by rotating a retractable wire loop.
Then, inspired by the work of Italian psychiatrist Amarro Fiamberti, Walter Freeman at some point conceived of approaching the frontal lobes through the eye sockets instead of through drilled holes in the skull. In 1945 he took an icepick from his own kitchen and began testing the idea on grapefruit and cadavers. This new "transorbital" lobotomy involved lifting the upper eyelid and placing the point of a thin surgical instrument (often called an orbitoclast or leucotome, although quite different from the wire loop leucotome described above) under the eyelid and against the top of the eyesocket. A mallet was used to drive the orbitoclast through the thin layer of bone and into the brain along the plane of the bridge of the nose, around fifteen degrees toward the interhemispherical fissure. The orbitoclast was mallated five centimetres into the frontal lobes, and then pivoted forty degrees at the orbit perforation so the tip cut toward the opposite side of the head (toward the nose). The instrument was returned to the neutral position and sent a further two centimetres into the brain, before being pivoted around twenty eight degrees each side, to cut outwards and again inwards (In a more radical variation at the end of the last cut described, the butt of the orbitoclast was forced upwards so the tool cut vertically down the side of the cortex of the interhemispherical fissure; the "Deep frontal cut".) All cuts were designed to transect the white fibrous matter connecting the cortical tissue of the prefrontal cortex to the thalamus. The leucotome was then withdrawn and the procedure repeated on the other side.
Freeman performed the first transorbital lobotomy on a live patient in 1946. Freeman was soon performing the brain operation for every complaint imaginable and anywhere he happened to be, even in his own office
Walter Freeman began to travel around the nation in his own personal van, which he called his “lobotomobile”, demonstrating transorbital lobotomy in any hospital that would have him. He even performed a few in hotel rooms, lobotomizing children as young as thirteen for “delinquent behavior” and housewives who had lost their zeal for domestic work.

In  the end he lost his license after killing a patient.