Altered interhemispheric and temporal lobe white matter microstructural organization in severe chronic schizophrenia

Area of Science:

• Neuroimaging
• Neuroscience
• Radiology

Background:

• Schizophrenia is associated with white matter (WM) microstructural abnormalities.
• Previous diffusion MRI studies indicate reduced fractional anisotropy (FA) in specific WM tracts.

Purpose of the Study:

• To investigate diffusion parameters in severe chronic schizophrenia using tract-based spatial statistics (TBSS).
• To identify specific WM regions affected by microstructural changes in treatment-resistant schizophrenia patients.

Main Methods:

• Diffusion MRI data acquired using a 64-direction sequence (b=1300 s/mm²) on a Siemens 1.5T scanner.
• 19 patients with chronic severe schizophrenia and 19 age/gender-matched healthy controls.
• Diagnosis confirmed via DSM-IV Structured Clinical Interview for DSM disorder (SCID).

Main Results:

• Significantly reduced FA and increased radial diffusivity observed in corpus callosum (genu, body, splenium), right internal capsule, right external capsule, and right temporal inferior longitudinal fasciculus.
• No significant increase in FA found in patients compared to controls.
• Reduced splenium FA correlated with longer illness duration.

Conclusions:

• Widespread abnormal diffusivity properties detected in callosal and temporal lobe WM in severe chronic schizophrenia, even without clozapine exposure.
• Deficits may stem from reduced axonal density, altered glial function, or myelin reduction.
• Findings highlight significant WM microstructural disorganization in chronic schizophrenia.