Postmortem studies in schizophrenia find reductions in GAD67,1, 2, 3 which is responsible for the majority of basal GABA synthesis in the cortex.6 The 1H-MRS GABA signal may reflect the entire GABA content of the voxel (that is, intracellular and extracellular, and involved in metabolism or neurotransmission). The gene discussed is GAD1; the disease is schizophrenia.