Mitochondrial dysfunction including altered brain energy metabolism has been implicated in the pathophysiology of schizophrenia. The aim of this study was to investigate prefrontal lactate(Lac) levels in patients with chronic schizophrenia. An increase of [LacmPFC] was observed in patients with chronic schizophrenia relative to healthy controls. This may be associated with glucose metabolism impairment and mitochondrial dysfunction resulting from oxidative stress. Indeed, oxidative damages can impair mitochondrial oxidative phosphorylation and enzyme activities of pyruvate dehydrogenase, leading to Lac production. Therefore, this study provides in vivo evidence supporting that oxidative stress and mitochondrial dysfunction may be involved in schizophrenia.