Animal studies show that cerebral lactate increases after electrically induced seizures. We investigated three adult psychiatric patients by means of localized proton and phosphorous magnetic resonance spectroscopy in order to evaluate if such effects can be observed after electroconvulsive therapy (ECT). None of the patients had changes in cerebral energy metabolism following ECT. Within the limitations of in-vivo spectroscopy in a clinical setting, our results suggest that if lactate production increases after ECT, this effect is either very short or increased perfusion causes an efficient efflux of cerebral lactate.