Objective: This study verified the relation between glutamate and psychosis together with the effect of electroconvulsive therapy (ECT) on anterior cingulate glutamate in patients with psychosis. Method: 2 groups were compared in the study: 25 drug naïve patients with early psychotic episode (less than one year duration) and 25 healthy subjects as control. Glutamate was measured by magnetic resonance spectroscopy (MRS) in the anterior cingulate cortex (ACC) in the 2 groups. Patients were examined again after ECT by MRS. Patients were assessed by Positive and Negative Syndrome Scale (PANSS), Clinical Global Impression (CGI) and the Global Assessment of Function (GAF). Cognitive functions were partially assessed by applying the Rey–Osterrieth Complex Figure Test (RCFT).Results: Patients (before ECT) showed significantly lower glutamate levels than controls. Also patients before ECT showed significantly lower glutamate levels than after ECT. Only total PANSS scores showed statistically significant negative correlation with the glutamate level before ECT.Conclusion: Glutamate level changes in psychosis and increases after ECT.