Electroconvulsive therapy（ECT）has been widely used, with some modification of its methods, for the treatment of refractory mental disorders. In Japan, brief-pulse ECT was approved in 2002 under conditions that well-trained psychiatrists should administer ECT and that modified ECT is mandatory. However,unmodified ECT is still often performed in Japan. We have to improve safety of ECT further. Major indications for ECT are depression and catatonia. Mechanisms of ECT are still unknown,but the neurogenesis hypothesis is promising. Furthermore, several brain stimulation techniques without seizure induction, such as transcranial magnetic stimulation, vagus nerve stimulation, deep brain stimulation and transcranial direct current stimulation, have been introduced for the treatment of refractory mental disorders. Ethical criteria must be determined for further research and treatment with these techniques.