A lobotomy is a surgical procedure that interrupts the nerves in the brain. Before the use of prescription drugs became wide-spread, a common treatment for severe mental illness was lobotomy.
The lobotomy was invented in 1935 and used fairly regularly for about twenty years to treat psychosis and other mental illnesses. It was always controversial, and once effective anti-psychosis medications were developed, it fell out of use. Lobotomy results in a calmed, but also often mentally dull patient. The word itself comes from the word lobe, as in a part of brain, combined with tomy, a medical suffix that means "a cutting."