DUP linked to orbital–frontal gray matter reductions
MedWire News: Results from a Canadian study suggest that increased duration of untreated psychosis (DUP) is associated with gray matter reductions in the orbital-frontal regions of the brain in first-episode psychosis patients.
"Longer DUP has been shown to be modestly but significantly associated with poor clinical and social outcomes," explain Ashok Malla (Douglas Mental Health University Institute, Montreal) and team.
They add: "It has been suggested that this may be mediated through toxic effects of psychosis on the structure and function of the brain."
To investigate further, the researchers studied 80 patients with a first episode of psychosis who were divided into two groups based on a median cut-off point of 18 weeks DUP.
Patients in the short-DUP group had a mean DUP of 7.9 weeks while those in the long-DUP group had a mean DUP of 113.7 weeks.
Regional brain volume was assessed using magnetic resonance imaging, and cognitive function was assessed using a neuropsychological battery of tests.
Analysis revealed that patients in the long-DUP group showed significant whole brain gray matter volume reductions compared with those in the short-DUP group, at a mean of 720 versus 748 ml.
Regarding specific regional differences, patients in the long-DUP group showed significant gray matter volume reductions in the bilateral medial frontal gyrus and the bilateral rectal gyrus, as well as in the postcentral gyrus and superior parietal lobule, compared with patients in the short-DUP group.
However, there were no significant differences in white matter or cerebral spinal fluid volumes between the two groups.
Also, both groups showed similar cognitive function, the researchers note in the journal Schizophrenia Research.
Malla and team conclude: "Patients with a longer delay in treatment of psychosis show a significant reduction in overall gray matter volume with specific reductions in the inferior-orbital region."
They add: "These results provide some support to a possible neurotoxic effect of prolonged untreated psychosis."
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By Mark Cowen