There is considerable interest in identifying biomarkers of antipsychotic response in schizophrenia. Glutamate is one key candidate. The development of brain imaging techniques for measuring brain glutamate levels has allowed this hypothesis to be tested directly in patients. This talk will present our ongoing research examining the relationship between brain glutamate levels and antipsychotic response in first-episode psychosis and in treatment-resistant schizophrenia. I will summarise our results from both our completed and ongoing studies, to consider whether glutamate imaging might be useful in the future to identify patients who would benefit from non-dopaminergic antipsychotic drugs and inform novel, glutamate-based, treatment strategies.