Grey matter excess in basal ganglia after early treatment in neuroleptic naïve, newly diagnosed schizophrenia

Background: Basalganglia volumetric increases have been reported in schizophrenic patients afterearly weeks of neuroleptictreatment. To validate the early effect of neuroleptics on brain plasticity, we explored the bilateral caudate nucleus volumetric differences in a prospective, longitudinal, cohort of anti-psychotic naïve individuals newlydiagnosed with schizophrenia. Methods: 14 patients (6 males, 8 females) had MRI brain scans before, and after 3 weeks of antipsychotic treatment. 128 slices, contiguous, 1.2 mm thick T1 scans were used for manual (region of interest) tracing. Caudate nucleus volumes were measured “blind” to the time of the scan using MEASURE software. All measurements were performed by two raters and the inter-rater reliability between the two raters was 0.95 using left and right caudate nuclei on 10 scans. To reduce inter-rater variance, results from one rater measuring all of the MRI scans was reported. The intra-class correlation coefficient (ICC) for this rater was 0.97 for 5 scans measured 3 weeks apart. Results: We found that patients treated for a mean of 3 weeks, compared to baseline, had a total caudate volume increase of 5.4% (2 tailed p < 0.001). The left caudate was increased by 3.5% (2 tailed p < 0.001) and the right caudate by 7.4% (2 tailed p < 0.002). Conclusions: This result provides evidence to confirm our preliminary voxel-based morphometric (VBM) analysis findings in this longitudinal cohort. Earlybasalganglia volumetric increase after anti-psychotic exposure suggests that drug-mediated neural plasticity occurs during clinical recovery