Altered white matter/gray matter proportions in the striatum of patients with schizophrenia: a volumetric MRI study.

OBJECTIVE: Anatomical structures of the striatum were studied in 58 patients with schizophrenia and 56 healthy comparison subjects of both genders matched for age and handedness.
METHOD: Magnetic resonance imaging scans were used to measure gray matter, white matter, and CSF volumes of the caudate, putamen, and nucleus accumbens in the left and the right hemispheres.
RESULTS: White matter/gray matter ratios of the striatal structures were significantly lower in patients than in healthy subjects. In patients, relative white matter volumes in the caudate and nucleus accumbens were reduced, whereas gray matter in the putamen was increased. The total accumbens volume did not differ by diagnosis, but left side accumbens was larger than right in the healthy subjects. The proportion of white matter was greater in women in both the patient and healthy comparison groups. Total caudate and putamen volumes demonstrated no differences due to diagnosis or laterality, but a negative correlation was found in patients between white matter volumes and increasing age. There were no significant correlations among total striatal volumes, white matter/gray matter ratios, age at onset of illness, or illness duration. An estimate of lifetime neuroleptic consumption was positively correlated with right gray matter volume of the putamen in male schizophrenia patients who received typical neuroleptics.
CONCLUSIONS: The proportion of white matter to gray matter tissue volumes of the caudate, putamen, and nucleus accumbens is altered in medicated chronic schizophrenia patients, but the total volumes are unchanged.