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Wave of schizophrenic brain loss uncovered
PNAS 2001; 98: 11650–11655
Schizophrenic teenagers undergo a wave of gray matter loss that envelops increasing amounts of cortex throughout adolescence, a study published in this week's Proceedings of the National Academy of Sciences reveals. The team says that more research is needed to find ways of halting this rapid tissue loss, which they liken to a 'forest fire'.
Researchers from the University of California, Los Angeles, led by Paul Thompson, used repeated magnetic resonance imaging and brain mapping algorithms to study a number of adolescents with early-onset schizophrenia. Scans were taken at two-year intervals at three time points to uncover the dynamics and timing of disease progression.
They found that the earliest deficits occurred in the parietal regions, which underlie visuospatial and associative thinking and are known to mediate adult deficits through environmental factors.
Over five years, the deficits spread to the temporal lobes, encompassing sensorimotor and dorsolateral prefrontal cortices, and the frontal eye fields. The patterns of cortical loss correlated closely with the severity of psychotic symptoms, and were echoed by neuromotor, auditory, visual, and frontal executive impairments.
The changes that are seen consistently in adult studies – deficits in the dorsolateral prefrontal cortex and superior temporal gyri – were the latest to appear.
Thompson commented: 'This is the first study to visualize how schizophrenia develops in the brain. Scientists have been perplexed about how schizophrenia progresses and whether there are any physical changes in the brain.
'It moved across the brain like a forest fire, destroying more tissue as the disease progressed.'
Thompson notes: 'Now that imaging can define the wildfire of change in the brain, it becomes easier to tell if new drugs are opposing it.' However, he added that although current antipsychotics have a beneficial effect on symptoms, they don't appear to oppose the spread of deficits in the brain. 'So I think the emphasis will shift to drugs that save cells and their connections,' he added.
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