Gray matter reductions evident in patients at high risk for psychosis
MedWire News: Individuals at ultra-high risk (UHR) for psychosis have specific gray matter volume reductions, with those who go on to develop full-blown psychosis showing greater specific regional reductions than those who do not, research shows.
Writing in the Archives of General Psychiatry, Stefania Tognin (King's College London, UK) and colleagues explain: "People experiencing possible prodromal symptoms of psychosis have a very high risk of developing the disorder, but it is not possible to predict, on the basis of their presenting clinical features, which individuals will subsequently become psychotic."
They add: "Recent neuroimaging studies suggest that there are volumetric [gray matter] differences between individuals at UHR for psychosis who later develop psychotic disorder and those who do not. However, the samples examined to date have been small, and the findings have been inconsistent."
To investigate further, the team studied whole-brain magnetic resonance imaging (MRI) data from 182 patients at UHR for psychosis and 167 mentally healthy individuals from five sites in four countries (Switzerland, Germany, Australia, UK).
UHR status was defined by the presence of at least one of the following features: attenuated psychotic symptoms, brief limited intermittent psychotic symptoms, and a first-degree relative with a psychotic disorder, plus a marked decline in social or occupational functioning.
Of the UHR patients, 48 (26.8%) developed full-blown psychosis over a mean 30.6-month follow-up period after undergoing MRI assessment.
Examination of the MRI data revealed that gray matter volume was significantly reduced in the UHR group, compared with controls, in three areas of the frontal cortex: the medial orbital gyrus, the gyrus rectus bilaterally, and the right anterior cingulate gyrus. The UHR patients did not have greater gray matter volume in any brain region compared with controls.
Medication use did not influence these findings, the researchers note.
Among the UHR patients, region of interest analysis revealed significantly reduced gray matter volume in the anterior left parahippocampal gyrus among patients who went on to develop full-blown psychosis compared with those who did not.
Tognin and team conclude: "UHR [for psychosis] is associated with alterations in regional gray matter volume, and in this population, reductions in the parahippocampal region may be specifically linked to the later onset of psychosis."
They add: "These findings suggest that neuroimaging data may facilitate the prediction of illness in individuals at high risk for psychosis and may inform the development of new interventions designed to delay or prevent its onset."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011
By Mark Cowen