UCLA brain researchers using a powerful new analysis technique have created the first images showing the devastating impact of schizophrenia on the brain. The findings, published in the Sept. 25 issue of the Proceedings of the National Academy of Sciences, show how a dynamic wave of tissue loss engulfs the brains of schizophrenic patients in their teenage years.
The findings may have key diagnostic implications. Aided by a better understanding of how psychosis develops, researchers can detect aberrant loss early and treat patients as early as possible. Future medications might fight the rapid loss of brain tissue, and their effectiveness could be assessed using the imaging technique.
"This is the first study to visualize how schizophrenia develops in the brain," said Paul Thompson, an assistant professor of neurology at the UCLA School of Medicine and the study's chief investigator. "Scientists have been perplexed about how schizophrenia progresses and whether there are any physical changes in the brain. We were stunned to see a spreading wave of tissue loss that began in a small region of the brain. It moved across the brain like a forest fire, destroying more tissue as the disease progressed."
Scientists at UCLA and the National Institute of Mental Health employed magnetic resonance imaging (MRI) technology to scan a group of teenagers repeatedly as they developed schizophrenia. Using a new image analysis method that detects very fine changes in the brain, the scientists detected gray matter loss of more than 10 percent first in the parietal, or outer, regions of the brain; this loss spread to engulf the rest of the brain over five years.
Patients with the worst brain tissue loss also had the worst symptoms, which included hallucinations, delusions, bizarre and psychotic thoughts, hearing voices, and depression. Schizophrenia affects an estimated 1 percent of Americans. Its causes are unknown, and the disease typically hits without warning in the late teens or 20s.
Researchers also detected a mild loss of brain tissue in healthy teenagers. Between ages 13 and 18, they lost about 1 percent gray matter per year in the parietal cortices, the region where the spreading wave began. In schizophrenics, this brain tissue loss gained momentum and swept into the sensory and motor regions. The frontal eye fields lost tissue fastest, at about 5 percent per year. These fields control eye movements, which often are disturbed in schizophrenic patients.
In another first, the brain-mapping technique reveals underlying changes in the brain's anatomical hardware as teenagers mature normally or develop psychosis. The identification of previously unseen waves of loss and key anatomical changes will allow scientists to establish powerful links between cognitive and behavioral changes and rapid changes in underlying brain structures.
The UCLA and NIMH researchers are also applying this new imaging approach to relatives of schizophrenic patients to screen them for early brain changes. The disease runs in families, but specific risk genes have not yet been found. Although the causes of the disease are currently unknown, some non-genetic trigger, in the teenage years, may activate the disease in some individuals but not others.