Schizophrenia was once considered to be a life sentence: once you were diagnosed, the damage was already done. But a new HMS study hints at a future when we may be able to interrupt this debilitating illness.
Dean Salisbury, HMS associate professor of psychiatry at McLean Hospital, and Robert McCarley, HMS professor of psychiatry at the VA Boston Healthcare System, have found both structural and functional evidence that schizophrenia is a progressive disorder, according to their report in the May Archives of General Psychiatry. “This changes our view of the disorder … and could possibly lead to a therapy that could arrest the course of schizophrenia,” said McCarley.
Researchers have debated whether or not schizophrenia, which attacks both the frontal and temporal lobes of the brain, is set at birth or develops over time. Previous magnetic resonance imaging (MRI) studies of schizophrenics showed no progressive changes in the brain, but a few studies near first hospitalization did show a change in brain size. Still, the results were controversial—stronger evidence was needed.
What researchers sought to uncover was a decrease in brain size that corresponded to a loss of brain function. Salisbury and McCarley found just that—a tight correlation between a brain wave called mismatch negativity (MMN) and the volume of the Heschl gyrus, a section of the temporal lobes.
MMN brain waves, caused by auditory cues, are tested by playing a series of identical beeps, with an occasional “oddball” beep thrown in. The brain automatically responds to this difference by producing an MMN, which originates from the Heschl gyrus.
In a series of three experiments spanning 18 months, McCarley and Salisbury found that schizophrenics’ MMN waves were initially normal, but quickly diminished over time. In one test group, 14 out of 16 schizophrenia patients displayed an MMN decline over time, and in an additional test, 11 out of 11 test subjects showed a combined decrease in Heschl gyrus volume and MMN response.
While the sample sizes were relatively small, the researchers noted that long-term studies with the psychiatrically ill can be difficult—half of their subjects never returned for further tests. However, McCarley and Salisbury are following up with another study of new patients as a replication sample.
Not only does the study give hope of ending the onslaught of schizophrenia, it provides a tool to monitor the process. “Drugs that try to halt the shrinkage [of the brain] can be developed, and we can use the MMN to track that,” said Salisbury.
Gregory Light, an assistant professor of psychiatry at the University of California, San Diego, who is not an author on the study, believes the work is groundbreaking: “It’s really a substantial contribution to the science of understanding schizophrenia,” he said.
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