A common biomarker of schizophrenia and bipolar disorder revealed

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"... Researchers ... reviewed and analyzed the findings of previous studies to further test this hypothesis and validate the existence of a psychosis spectrum of disorders. Their paper, published in Nature Mental Health, outlines common brain features in patients with schizophrenia and BD, particularly differences in the integrity of white matter. ...

Most notably, they observed shared white matter alterations in a region called the corpus callosum. This is a brain structure that connects the brain's left and right hemispheres.

"This alteration was observed across the entire psychosis spectrum, rather than being limited to a single diagnosis," said Saccaro. "Importantly, these findings remained significant (and in some cases became clearer) after accounting for age and sex, suggesting they are unlikely to be explained simply by illness duration or aging. This supports the idea that disruptions in brain connectivity may represent a core biological feature of psychosis." ..."

From the abstract:

"Psychotic and mood disorders, including schizophrenia and bipolar disorder, are increasingly viewed as part of a psychosis spectrum disorder (PSD) continuum, sharing genetic and neurobiological features.

This systematic review and meta-analysis examines fractional anisotropy and mean diffusivity using diffusion tensor imaging in PSD. Across 96 studies (N = 4,424 PSD, N = 5,004 controls for fractional anisotropy; N = 1,607 PSD, N = 1,709 controls for mean diffusivity), fractional anisotropy reductions were consistently observed in the corpus callosum, whereas mean diffusivity increases were found in cortico-spinal projections.

Controlling for age and gender strengthened these findings, suggesting that they contribute to PSD pathophysiology rather than reflecting disease progression. Subgroup analyses revealed overlapping but distinct patterns in schizophrenia and bipolar disorder. These findings support a transdiagnostic model of psychosis, with corpus callosum abnormalities as a potential biomarker. Future longitudinal studies are needed to clarify causality and clinical implications."

A common biomarker of schizophrenia and bipolar disorder revealed

A systematic review and meta-analysis of transdiagnostic impairments in white matter integrity across the psychosis continuum (no public access)

Reduced FA, psychosis spectrum, TBSS studies only, corrected for age and gender.