By Mark Cowen, Senior medwireNews Reporter
Sexual abuse in childhood is associated with significant gray matter volume reductions in patients with psychosis, US researchers report.
Stephan Heckers and colleagues from Vanderbilt University in Nashville, Tennessee, also found that severity of childhood sexual abuse was positively associated with greater gray matter volume reductions in psychosis patients.
"These findings indicate that some of the variance of gray matter volume in psychotic disorders can be explained by a history of sexual abuse," they write in Schizophrenia Research.
The researchers studied of 60 patients with psychotic disorders and 26 mentally healthy individuals (controls) who were aged between 16 and 65 years.
All of the participants completed the short version of the Childhood Trauma Questionnaire (CTQ), and underwent magnetic resonance imaging of the brain.
After accounting for age and gender, the team found that there was a significant negative correlation between CTQ subscores for sexual abuse and gray matter volume in psychosis patients. However, there were no significant correlations between other CTQ subscales (physical abuse, emotional abuse, emotional neglect, and physical neglect) and gray matter volume in the patients.
The researchers also found that psychotic patients with a history of sexual abuse (n=24) had significantly reduced gray matter volume compared with 26 demographically matched psychotic patients without such abuse and controls.
Interestingly, psychotic disorder patients without a history of sexual abuse did not differ from controls regarding overall gray matter volume, note the authors.
Analysis of regional gray matter volume showed that patients with psychotic disorders had reduced gray matter volume in the frontal lobes, occipital lobes, and cerebellum compared with controls.
Among the psychotic patients, those with a history of sexual abuse had reduced gray matter volume in bilateral frontal regions compared with those without such a history.
Heckers et al conclude: "Our results show that classifying individuals by diagnosis alone may not be enough to uncover brain abnormalities in psychotic disorders. Instead, it may be necessary to explore environmental risk factors, such as childhood trauma, in order to better understand individual differences in brain morphology, particularly gray matter loss."
They add: "Since psychotic disorder patients report more abuse than healthy controls, stratification of patient samples by trauma history appears to be a fruitful approach for future studies of brain structure and function in psychosis."
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