Schizophrenia frequently manifests psychotic symptoms, such as delusions and hallucinations. However, its neurochemical mechanisms are not well deciphered, though dysfunctional dopaminergic neurotransmission is suggested. In this study, single volume 1H MRS using MEGA-PRESS at 3 T was applied to investigate possible neurochemical changes in the visual cortex induced by pharmacologically increased dopamine levels in healthy volunteers that also performed a visual detection task. Increased dopamine yielded decreased GABA and reduced glutamate quantities. Furthermore, an inverse correlation of glutamate with false perceptions in the detection task supports the theory that glutamate hypofunction might contribute to the formation of hallucinations in schizophrenia.