A longitudinal study on the effects of typical versus atypical antipsychotic drugs on hippocampal volume in schizophrenia.

Background: Previous studies have reported that hippocampal volumes correlate with symptom severity in schizophrenia. This longitudinal study measured changes in symptoms and hippocampal volume in patients switched from typical antipsychotics to olanzapine.

Methods: MRI scans were acquired from patients with chronic schizophrenia (n=10) and healthy volunteers (n=20). At baseline, patients were treated with typical antipsychotics for at least one year, then switched to olanzapine, and rescanned approximately one year later.

Results: Olanzapine treatment resulted in no significant change in right or left hippocampal volume. Individual changes in right hippocampal volume correlated significantly with changes in symptoms.

Conclusions: Hippocampal volume change may serve as a marker of symptom change in patients on olanzapine.