Old methods
Insulin shock treatment is an old and currently mostly abandoned treatment of severe depressions, psychoses, catatonic states and other mental disorders. It consists of induction of hypoglycemic coma by intravenous infusion of insulin. The treatment is potentially unsafe and can be lethal in some cases (about 1% of patients undergoing insulin coma), even with proper monitoring. That was the main reason why it was abandoned from current medical practice. In contrast, ECT is considered to be very safe.
Nevertheless, insulin shock therapy is still officially used in Russia and some other countries, and can be administered to a very treatment-resistant patient under his written consent in many Western countries.