eople who do not want to wait for old age to
shrink their brains and bring on memory loss now have a quicker
alternative - abuse methamphetamine for a decade or so and watch the
brain cells vanish into the night.
The first high-resolution M.R.I. study of methamphetamine addicts
shows "a forest fire of brain damage," said Dr. Paul Thompson, an
expert on brain mapping at the University of California, Los
Angeles. "We expected some brain changes but didn't expect so much
tissue to be destroyed."
The image, published in the June 30 issue of The Journal of
Neuroscience, shows the brain's surface and deeper limbic system.
Red areas show the greatest tissue loss.
The limbic region, involved in drug craving, reward, mood and
emotion, lost 11 percent of its tissue. "The cells are dead and
gone," Dr. Thompson said. Addicts were depressed, anxious and unable
to concentrate.
The brain's center for making new memories, the hippocampus, lost
8 percent of its tissue, comparable to the brain deficits in early
Alzheimer's. The methamphetamine addicts fared significantly worse
on memory tests than healthy people the same age.
The study examined 22 people in their 30's who had used
methamphetamine for 10 years, mostly by smoking it, and 21 controls
matched for age. On average, the addicts used an average of four
grams a week and said they had been high on 19 of the 30 days before
the study began.
Methamphetamine is an addictive stimulant made in clandestine
laboratories nationwide. When taken by mouth, snorted, injected or
smoked, it produces intense pleasure by releasing the brain's reward
chemical, dopamine. With chronic use, the brains that overstimulate
dopamine and another brain chemical, serotonin, are permanently
compromised.
The study held one other surprise, Dr. Thompson said: white
matter, composed of nerve fibers that connect different areas, was
severely inflamed, making the addicts' brains 10 percent larger than
normal. "This was shocking," he said. But there was one piece of
good news: the white matter was not dead. With abstinence, it might
recover.
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