ECT is the most powerful treatment of severe melancholic/ psychotic depression. A treatment series consists of 8-12 sessions, given 3 times a week under anaesthesia, muscle relaxation and artificial ventilation with 100% oxygen. EEG, EMG, EKG and pulse oximetry are monitored. Benzodiazepines, anticonvulsants and lithium salts should be avoided during treatment with ECT. Ambulatory single ECT sessions with an interval of 3-4 weeks (maintenance-ECT) is recommended in drug-resistant depression. In Denmark, 5% of all patients admitted to psychiatric departments were treated with ECT; 18% of patients diagnosed with depression were given ECT. ECT is a safe and sometimes life-saving treatment.