Electroconvulsive therapy (ECT) has recently been re-examined in randomized, double-blind controlled trials. Although a variable placebo influence has been demonstrated, the effectiveness of ECT in severe depression is now well established. ECT may also have a role in the treatment of resistant schizophrenia. A bilateral convulsion is essential for therapeutic efficiency. Unilateral electrode placement is as effective as bilateral placement and reduces subsequent memory impairment considerably. A reduction in the total electrical energy used to produce the convulsion (with unidirectional squared wave forms and brief pulses) lessens cognitive difficulties after ECT. Long-term memory is not impaired but selective impairment of verbal and non-verbal learning can occur in the short term. Psychopharmacological studies suggest that postsynaptic dopamine transmission may be enhanced by ECT.