Similar white matter changes in schizophrenia and bipolar disorder: A tract-based spatial statistics study

Area of Science:

• Neuroscience
• Psychiatry
• Radiology

Background:

• Schizophrenia (SCZ) and Bipolar Disorder (BD) exhibit overlapping clinical symptoms, epidemiology, and treatment responses.
• Shared neurobiological correlates between SCZ and BD remain inconclusive.
• Understanding common microstructural brain alterations is crucial for diagnosing and treating these major psychoses.

Purpose of the Study:

• To investigate common microstructural brain alterations in patients with SCZ and BD using diffusion tensor imaging (DTI).
• To compare DTI-derived metrics between SCZ, BD, and healthy controls.
• To explore correlations between microstructural changes and clinical variables.

Main Methods:

• Acquisition of Magnetic Resonance Diffusion data from 33 BD patients, 19 SCZ patients, and 35 healthy controls.
• Calculation of DTI indexes including mean diffusion (MD), volume ratio (VR), radial diffusivity (RD), fractional anisotropy (FA), and mode (MO).
• Analysis using Tract-Based Spatial Statistics (TBSS) to identify group differences and correlations.

Main Results:

• Both SCZ and BD groups showed increased MD, VR, and RD, and decreased FA and MO compared to controls.
• Diffusion changes were localized in fronto-temporal and callosal networks in both patient groups.
• No significant differences in diffusion indexes were found between SCZ and BD groups.

Conclusions:

• SCZ and BD share similar white matter microstructural impairments, particularly affecting fronto-temporal and callosal networks.
• These shared alterations suggest common neural underpinnings for major psychoses.
• The findings highlight the central role of white matter pathology in SCZ and BD and suggest potential disease progression.