Early case reports note marked improvements in the signs of Parkinson's disease (PD) in several patients with coexisting psychiatric disorders after treatment with electroconvulsive therapy (ECT). Studies since 1959 reveal improvement of parkinsonism in over half of PD patients receiving ECT, regardless of the presence or absence of psychiatric comorbidity. Drug-induced parkinsonism, tardive dystonia, and tardive dyskinesia have also been shown to improve with ECT administration; tic syndromes have achieved mixed results. In animals, ECT enhances dopamine-mediated effects and increases GABA concentrations in the CNS. Optimal parameters relevant to the antiparkinsonism effects of ECT require further study.