My roommates and I are having an argument about electroshock therapy after watching Jack in One Flew Over the Cuckoo's Nest. But don't worry, we'll delve into the question of twitching, too. Electroshock, more formally known as electroconvulsive therapy or ECT, was one of four radical techniques introduced in the 1930s to treat mental illness. Besides electroshock there was lobotomy, insulin coma therapy, and metrazol convulsion therapy.
Electroshock is the only one still in common use.
For ECT the patient was placed on a gurney, and electrodes were applied to the temples or other points on the skull. In the early days a stiff jolt of house current was applied without further ado, and the patient went into convulsions lasting a minute or so. The spasms were sometimes violent and in about 1 percent of cases the patient suffered a broken bone or dislocation. In later years doctors began using anesthetics to knock the patient out plus a muscle relaxant to eliminate injuries. So to answer your question, patients twitched big-time in the old days but relatively little now.