ECT is the most effective and rapidly-acting treatment for severe depressive disorders. It is usually reserved for patients who have failed to respond to drug or other therapies, but it can be a first line treatment. It is particularly indicated for severely depressed patients who are at risk of suicide or at risk of death because of their refusal to eat or drink. There is a firm evidence base for the effectiveness of ECT. It also has a place in the treatment of other disorders such as schizophrenia, mania, catatonia and neuroleptic malignant syndrome. Its role in these conditions is usually when drug therapy has proved ineffective or for some reason is inadvisable. Other areas explored in this council report are: what is an ECT?; how does ECT work?; what adverse effects does ECT cause?; accommodation and plant; staffing; protocols; and audit.