July 20, 2004

This Is Your Brain on Meth: A 'Forest Fire' of Damage

People 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.