Brain regions linked to poor insight in first-onset psychosis confirmed
MedWire News: Results from a UK study indicate that the cingulate gyrus and the right precuneus/cuneus areas of the brain are involved in poor insight among patients with a first-onset psychosis.
"Several studies have suggested that neuropsychological and structural brain deficits are implicated in poor insight," explain Kevin Morgan (University of Westminster, London) and colleagues in the British Journal of Psychiatry.
"There is, however, some inconsistency in these findings," they add.
To investigate further, the researchers studied 82 patients, aged 16-65 years, from inner-city London with first-onset psychosis who participated in the Aetiology and Ethnicity in Schizophrenia and Other Psychoses study and 91 mentally healthy controls from the same area.
All the participants underwent voxel-based magnetic resonance imaging of the brain.
They were also interviewed using the Schedule for the Assessment of Insight - Expanded version (SAI-E), with a focus on symptom relabeling and overall illness awareness in the psychosis patients.
A cognitive test battery was used to assess premorbid intelligence, current IQ, psychomotor speed, spatial ability, verbal fluency, set shifting, auditory working memory, and verbal and non-verbal memory.
Total grey matter volume was reduced by 2.5% in the psychosis compared with the control group, while lateral ventricular volume was 6.4% larger in the psychosis group, with the psychosis group having a larger lateral ventricle to brain volume ratio than the control group.
After adjustment for multiple comparisons, the researchers found that symptom relabeling significantly correlated with performance IQ, while total insight significantly correlated with performance IQ and verbal learning.
Further analysis shows that among patients with psychosis, those with no symptom relabeling ability (n=20) had significant global and regional grey matter reductions primarily in the posterior cingulate gyrus and right precuneus/cuneus compared with those with at least some symptom relabeling ability (n=62).
Total grey tissue volume in the patients without symptom relabeling ability was 6.7% lower than in those with some relabeling ability.
Stepwise linear regression analysis controlling for diagnostic status revealed significant effects for right hemisphere cuneus grey matter reductions and deficits and performance IQ scores accounting for 31% of the variance in symptom relabeling.
Morgan and team conclude: "The cingulate gyrus (as part of a midline cortical system) along with right hemisphere regions may be involved in illness and symptom self-appraisal in first-onset psychosis."
They add: "Further evidence that neurocognitive deficits underpin the most severe incapacity to identifying psychotic states as pathological may be of importance clinically in setting a limit upon expectations for recovery."
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By Mark Cowen