Jun 20 2012
By Mark Cowen
Results from an Irish study show that poor insight is associated with increased gray matter volume in subcortical and frontotemporal brain regions among patients with first-episode psychosis (FEP), but not in those with chronic schizophrenia.
"The regional grey matter excesses may reflect neuroplastic changes which are prominent in individuals during their first episode of psychosis attempting to rationalize particular symptoms outside an illness model," comment John McFarland (National University of Ireland, Galway) and team.
The findings come from a study of 32 FEP patients and 30 patients with chronic schizophrenia who were aged between 16 and 50 years. All of the FEP patients had received less than 6 weeks of treatment with antipsychotics.
The participants were evaluated using the Scale to Assess Unawareness of Mental Disorder (SUMD), and magnetic resonance imaging scans were used to measure gray matter volume.
Overall, there was no significant association between SUMD awareness and gray matter volume in the FEP patients.
However, insight impairment, as measured by SUMD symptom misattribution, was associated with increased gray matter volume in the right and left caudate, right thalamus, left insula, putamen, and cerebellum.
The association remained true after accounting for medication exposure, duration of untreated psychosis, and symptom severity.
Insight impairment was not associated with gray matter deficits in any brain region among the FEP patients.
Among the patients with chronic schizophrenia, there was no significant relationship between gray matter volume in any brain region and measures of insight.
"It is possible that lengthy exposure to multiple medications and effects of illness progression on brain structure may have obscured any association of insight variation with gray matter volume in this patient group with chronic illness," comment the authors.
McFarland et al conclude in the European Archives of Psychiatry and Clinical Neuroscience: "Our results provide further evidence for a neurobiological basis underlying insight deficits in FEP."
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