Compared to many biological treatments used in psychiatry, ECT is quite old, dating back to the 1930s. Over its long history, the use of ECT has been considerably refined and it is now used much more carefully than it was fifty years ago. In the past, ECT was commonly used with a much wider range of disorders than it is now. Sometimes it was used simply for behavioral control. Today it is mainly used to treat depression, although it can also treat mania and psychosis.

Much higher dosages of electricity were used in the past than are used today. Bilateral ECT, in which electrodes are placed on both sides of the head, was the norm, while unilateral ECT is frequently used today. Unilateral ECT tends to have fewer side effects though it is not as powerful as bilateral ECT.

Finally, muscle relaxants were not commonly used, so patients could get hurt during seizures, even breaking bones. Currently, patients are given muscle relaxants and put under general anaesthesia prior to ECT. When they wake up they have no memory of the procedure. Additionally, electronic monitoring machines help ensure that breathing and heartbeat remain normal throughout the procedure.