We investigated whether the caudate nuclei volume (CNV) of 15 first episode psychosis patients increased after 5 years of treatment with either atypical antipsychotics or low doses of typical antipsychotics. Caudate volumes were measured from magnetic resonance imaging (MRI) scans in 15 patients and 10 healthy controls. Both groups demonstrated a significant 9% decline in caudate volume. We were unable to replicate previous reports of caudate enlargement in patients receiving antipsychotic treatment.