Shock therapy is the use of drugs or electricity to treat severe mental disorders by inducing coma or convulsions. Insulin therapy uses injections of increasing levels of insulin, deoxygenating the blood and producing a deep coma with diffuse motor, sensory, and autonomic effects. The therapeutic effect seems to be greatest with schizophrenias (see schizophrenia) of less than two years' duration and of good prognosis. Metrazol has also been used to produce convulsions. Complications include difficulties in controlling the reaction and intense fear experienced by the patient prior to losing consciousness.
Electroconvulsive therapy (ECT), over the years, has usually involved a brief passage of about 150 volts of DC electric current between two electrodes placed on the patient's temples. The current, which causes convulsions and loss of consciousness, would be administered about three times weekly for two to six weeks. Side effects included temporary memory loss and intellectual impairment, with a slight risk of fractures and respiratory failure. In recent years such side effects have been reduced by a modified treatment involving a much lower current and sometimes a reduced number of sessions. In addition, ECT recipients are now briefly anesthetized and given muscle relaxants, and their brain waves and heart rhythms are monitored. Frequently only a single electrode is used.
In the mid-20th century the practice of ECT was sometimes abused through its indiscriminate application to patients in mental hospitals. It has since been supplanted for many conditions by treatment with psychotherapeutic drugs, but in the 1980s there was a resurgence in its use with patients suffering life-threatening depression. It also continues to be used with a small percentage of other ailments, including treatment of the melancholia experienced by some patients with Parkinson' s Disease. The action of ECT may be linked with the increase in blood levels of beta endorphin observed by patients after shock treatment, since endorphins are the body's so-called natural opiates.