OBJECTIVE: Proton magnetic resonance spectroscopy (1H-MRS) studies of medicated patients with schizophrenia suggest high choline levels in the caudate nucleus. However, assessments of antipsychotic-naive patients are needed. METHOD: The authors studied 11 antipsychotic-naive schizophrenia patients and 11 normal comparison subjects with single-voxel 1H-MRS of the left caudate nucleus. Concentrations of N-acetylaspartate, choline, and creatine were determined and corrected for the proportion of cerebrospinal fluid in the voxel. RESULTS: The patients with schizophrenia had significantly higher levels of choline than the comparison subjects, while the other two metabolites did not differ between groups. CONCLUSIONS: High caudate choline levels in schizophrenia are not secondary to antipsychotic treatment.