The caudate nucleus is involved in cognitive function. Schizophrenic patients showed cognitive dysfunction. It has been reported that volume reduction of the caudate nucleus was associated with cognitive impairment in schizophrenic patients. Because treatment with olanzapine improves cognitive dysfunction in schizophrenia, olanzapine may affect the caudate nucleus volume in patients with schizophrenia. We measured volumes of grey and white matter in the caudate nucleus of schizophrenic patients.

Ten schizophrenic patients and ten healthy subjects were examined magnetic resonance imaging. Ten patients were scanned at the time of pre-treatment and post-treatment with olanzapine. MR data analysis was performed using BRAINS software in order to measure grey and white matter volume of the caudate nucleus.

Schizophrenic patients had reduced volume of grey and white matter of the caudate nucleus compared with healthy subjects. The average duration of treatment with olanzapine was 186 days in schizophrenic patients. The volume of grey and white matter in the caudate nucleus at the time of post-treatment was significant larger than that at the time of pre-treatment with olanzapine in patients with schizophrenia. There was no significant difference between the volume of grey matter of the caudate nucleus at the post-treatment with olanzapine and that of healthy subjects.

Schizophrenic patients had reduced volume of the caudate nucleus. Treatment with olanzapine may improve volume reduction of grey matter of the caudate nucleus in schizophrenic patients.