Bilateral caudate caudate volume deficits in never-treated schizophrenia

Abstract

BACKGROUND: Neuroleptic medication and chronic illness are important confounders when examining brain structure in schizophrenia. We hypothesised that never-treated subjects with schizophrenia would have smaller caudate nuclei compared to healthy controls. METHODS: We recruited 41 subjects with first episode schizophrenia and 40 healthy controls. Groups were balanced for age, sex, handedness, ethnicity, paternal socio-economic status, height. 29 of the subjects with schizophrenia were neuroleptic-nay¨ve. All participants participants had T1 brain scans of slice thickness 1.2mm thick, contiguous, 128 slices. Region of interest measurement of the caudate was done using MEASURE (Barta et al 1997). Axial scans were first aligned along the AC-PC by an independent operator blind to group membership. There were no significant whole brain volume difference between patients and controls. Caudate nuclei were traced according to standard anatomical boundaries (Cahn et al, 2002) and volumes calculated by summed pixel cross-sectional areas X slice thickness. Results: ICC for total caudate volumes on 10 scans at 1 month apart was 95%. Caudate volume was significantly smaller in neuroleptic-naı¨ve patients by 11% on the left (95% C.I of difference -.89, -0.29, p < 0.001) and 13% on the right. (95% C.I. of difference -0.77, -0.15, p < 0.004). In contrast, there were no caudate volume differences between healthy controls and a separate group of schizophrenic patients who had received 3 weeks of neuroleptic treatment (n=12, balanced for socio-demographic parameters). COnclusions: Smaller caudate volumes may represent a possible biomarker for schizophrenia, which appears to bnormaliseQ in the early weeks of neuroleptic treatment.