Scimex: An imaging study from NeuRA’s Schizophrenia Laboratory has confirmed that changes in IQ in people with schizophrenia are related to reduced volume in the brain, and that brain regions are differently affected. Cognitive deficits in schizophrenia, although they can differ from person to person, are one of the core symptoms of the disorder. Earlier work from Associate Professor Tom Weickert’s lab proposed an IQ-based classification system, centred on IQ trajectories from before illness to after illness onset that could identify three distinct subgroups of schizophrenia.
These three subgroups included those who had a large and significant
IQ decrease from before to after illness onset (called the deteriorated
group); those whose IQ did not appear to change after illness onset
staying around or above average before and after illness onset (called
the preserved group); and those who displayed consistently low IQ levels
before and after illness onset (called the compromised group).
New research has built on this earlier classification work by
establishing whether these different intellectual subgroups are
associated with any structural changes in the brain. They examined
differences in brain volume and were able to confirm that the IQ-based
classifications are indeed related to underlying neurobiological
differences, and that distinct brain regions may be differentially
affected in each subgroup.
The study found that the deteriorated group could be further divided
into two subsets – moderately and severely deteriorated subgroups. The
severely deteriorated subgroup had significantly reduced brain volume in
regions of the brain important for memory, social cognition, language
and visual processing, which correspond to more severe negative symptoms
(reduced emotions, motivation and social interactions) in the severely
deteriorated subgroup in comparison to the preserved group.
"Our recent findings on cognitive IQ-based subgroups provides a
strategy to aid in the prediction of how each subgroup would respond to
novel therapies to improve cognition and functional abilities in people
with schizophrenia,” Assoc Prof Tom Weickert said.