ECT, in which first experiments were made by the italian Cerletti more than half a century ago, underwent, in the seventies, a definite decline, as it was less and less applied to patients, a result of the influence of anti psychiatry. During the last fifteen years, there has been a legitimate renewal of the interest for this therapy; its indications seem now well codified and its techniques and practises have evolved considerably. Actually, in order to carry out ECT under general anaesthesia, it is necessary to have a pluridisciplinary team, assembling nurses, anaesthesists and psychiatrists that will use more and more effective appliances and adequate anaesthetics. Many of the parameters able to influence ECT's effectiveness are now well known and can be used and adapted according the individual characteristics of each patient. These parameters are: the lateralisation of the electrodes, the intensity of the electric current, the duration of the epileptic fit, the modification that appear in electroencephalography and the frequence of the sessions. According to different investigations, it seems that we must systematically question the medical treatments we associate to ECT. For instance, it is highly recommended not to prescribe with ECT benzodiazepines or antiepileptic mood stabilizers, while antidepressants or neuroleptics do not seem to exert any influence on the effectiveness of the treatment. Some authors think caffeine and triiodothyronin (T3) could have an interesting effect when combined with ECT. As to the indications of shock therapy, they can be now more and more precisely defined making of this treatment an indispensable instrument in the cure of depressive disorders. But ECT is also appropriate in maniac disorders once neuroleptic treatment has failed or else in the very beginning in highly acute cases, and mainly in mixed episodes for which medical treatment is often difficult to adapt. In schizophrenia, ECT can also be prescribed in definite circumstances as catatonia, paranoid states or schizoaffective episodes. Therefore, ECT constitutes a safe and comfortable therapy for the patient since its side effects are essentially characterized by cognitive disorders, and its main contraindications consist of severe cardiovascular diseases. ECT is also an essential tool in some definite cases.