Brain language structures altered in patients at genetic risk for schizophrenia

By Mark Cowen, Senior MedWire Reporter

Mentally healthy individuals with a family history of schizophrenia display alterations in brain areas associated with language, US researchers report.

The findings, published in Schizophrenia Research, suggest that such alterations may be trait markers associated with genetic vulnerability to schizophrenia, rather than specific markers resulting from processes underlying development of the mental health disorder.

Lynn DeLisi (Harvard Medical School, Boston, Massachusetts) and team studied 46 nonpsychotic individuals (32 women), aged an average of 25 years, at high familial risk (FHR) for schizophrenia. These participants had at least one first degree family member with schizophrenia and one second- or third-degree relative with a history of a psychosis, suicide, or psychiatric hospitalization.

A control group of 31 mentally healthy individuals (18 women), aged an average of 18 years, without a family history of psychosis were also enrolled.

All of the participants underwent magnetic resonance imaging of the brain and completed a battery of 11 verbal neuropsychological tests.

There were no significant differences between the groups regarding performance on the language tests, the researchers note.

However, region-of-interest analysis showed that FHR participants had significant gray matter deficits in the left pars triangularis and right pars orbitalis of the ventrolateral prefrontal cortex compared with controls.

Furthermore, the normal left to right asymmetry of the pars orbitalis was reversed in FHR participants compared with controls.

The researchers also found that left pars triangularis and right pars orbitalis gray matter volumes correlated with performance on language function tests in FHR participants, but not in controls.

DeLisi et al conclude: "Reduced volume and reversed structural asymmetry in language-related regions hypothesized to be altered in schizophrenia are also found in first degree relatives at FHR, despite normal language performance."

They say that further studies are now needed to clarify whether these findings are endophenotypes for schizophrenia.

In addition, "measures of complex language need to be studied to determine if FHR individuals manifest impairments in some aspects of language function."

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