Study charts path of brain damage in schizophrenia

By Amy Norton

NEW YORK, Sep 24 (Reuters Health) - A new brain imaging study has uncovered the path of destruction that schizophrenia appears to take as it progresses--what researchers call a "wildfire" of tissue loss that occurs in the brains of teens with the psychiatric disorder.

Such images could prove useful in developing drugs that fight the brain tissue loss and in monitoring whether existing medications bring measurable benefits to patients' brains.

The new research involved 12 patients who began showing schizophrenic symptoms early in life, by age 12. But the study's lead author told Reuters Health that the same brain changes likely occur in patients who develop symptoms in their late teens and early 20s--the most common time for the disorder to appear.

Dr. Paul Thompson and his colleagues compared brain scans of these patients with those of healthy teens, charting structural changes that occurred over 5 years.

What the investigators found was a "dynamic wave of change" in the schizophrenics' brains that arose hand-in-hand with worsening symptoms, according to Thompson, an assistant professor of neurology at the University of California, Los Angeles.

It all started with a small area of loss in the parietal region, an area connected to functions such as logical thinking, Thompson explained in an interview.

From there, tissue loss accelerated and swept across the brain, affecting areas key to basic functioning like movement and hearing. This widespread assault on the brain reflects the cluster of symptoms that mark schizophrenia, which include an altered perception of reality, disordered thinking and a lack of emotional responsiveness.

The findings are published in the September 25th issue of Proceedings of the National Academy of Sciences.

Schizophrenia is a complex brain disorder whose cause remains elusive. But it is known to run in families, and scientists believe that genes, developmental factors and environment act in concert to trigger the disorder.

One of the intriguing findings in this study, Thompson said, is that even the healthy teens showed some slight brain tissue loss. This, he noted, puts forth the possibility that schizophrenia arises from an abnormal acceleration or alteration in this apparently normal loss. It is unclear what might trigger such a scenario.

However, Thompson said, certain brain areas affected in schizophrenia are vulnerable to stress--such as that resulting from psychological trauma or physical illness.

Scientists also speculate that prenatal exposure to infection or malnutrition may make people vulnerable to schizophrenia later on. But Thompson said this study, in which brain tissue loss clearly took off in the early teens, suggests scientists should also examine this point in life.

"It's been a really big puzzle what the cause of schizophrenia is," he noted. Right now, he added, researchers are "trying to make all the puzzle pieces fit."

But a more immediate and practical use of these findings may be in monitoring how well schizophrenia drugs work, according to Thompson. The results, he said, offer "something really concrete in the brain" that could reveal whether a drug is actually halting the disease's progression.

SOURCE: Proceedings of the National Academy of Sciences 2001;98.

Copyright © 2001 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.