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Research indicates heterogeneity of schizophrenia

Recent findings suggest that schizophrenia is a heterogeneous group of disorders that can be distinguished by different patterns of fractional anisotropy reductions associated with clinical symptoms.

“Unfortunately, [diffusion-tensor images] findings in [schizophrenia] have been inconsistent across studies. Specifically, studies have either reported no white matter [functional anisotropy] differences between controls and patients with [schizophrenia], minimal regional [functional anisotropy] abnormalities, or widespread [functional anisotropy] abnormalities,” the researchers wrote. “The inconsistencies in [schizophrenia] studies may arise from averaging heterogeneous groups of patients with varying [fractional anisotropy] abnormalities.”

To determine if schizophrenia is a heterogeneous group of disorders distinguished by patterns of fractional anisotropy reductions, researchers developed a Generalized Factorization Method (GFM) to identify subsets of particular characteristics — or “biclusters” — among 47 individuals with schizophrenia and 36 healthy individuals.

Researchers identified eight biclusters.

C. Robert Cloninger

The mean fractional anisotropy of the voxels of each bicluster was significantly different compared with other participants with schizophrenia and healthy controls.

Researchers organized the eight biclusters into four more general patterns of low fractional anisotropy in specific regions, including the 1) genu of corpus callosum; 2) fornix and external capsule; 3) splenium of corpus callosum, retrolenticular limb and posterior limb of the internal capsule; and 4) anterior limb of interior capsule.

The patterns were significantly associated with clinical features, according to researchers.

The first pattern was associated with bizarre behavior and the second pattern was associated with prominent delusions.

The third pattern was associated with negative symptoms, including disorganized speech.

“By looking at the brain’s anatomy, we’ve shown there are distinct subgroups of patients with a schizophrenia diagnosis that correlates with symptoms,” C. Robert Cloninger, MD, PhD, of the Washington University School of Medicine, said in a press release. “This gives us a new way of thinking about the disease. We know that not all patients with schizophrenia have the same issues, and this helps us understand why.” – by Amanda Oldt

Disclosure: The researchers report no relevant financial disclosures.