ECT is still considered, by many, to be psychiatry's most controversial if not most risky treatment. Originally discovered by accident in 1938 by Dr. Ugo Cerletti he soon realized it was ideal to subdue pigs to be slaughtered.

In 1938 Dr. Ugo Cerletti became interested that pigs were prepared for slaughter by being electrically shocked through the temples. This rendered them unconscious but did not kill them, indeed they could survive the shock if allowed to recover. Deciding to try it on his patients Dr Cerletti found such electric shocks caused his obsessive and difficult mental patients to become meek and manageable. Large quantities of insulin also chemically shocked patients into a coma that lasted about an hour and was also starting to be used. Other doctors quickly adopted these new therapies.

Electroconvulsive therapy can differ in its application in three ways: electrode placement, frequency of treatments, and the electrical waveform of the stimulus. These three forms of application have significant differences in both adverse side effects and positive outcomes. After treatment, drug therapy is usually continued, and some patients receive continuation/maintenance ECT. In the United Kingdom and Ireland, drug therapy is continued during ECT.