This Is Your Brain on Speed
March 1, 2001 -- The bad news is that regular use of the highly addictive drug methamphetamine can cause lingering problems with short-term memory and motor coordination. The worse news is that the damage doesn't seem to go away when you stop abusing the drug -- or at least not quickly.
These grim conclusions were reported Thursday in the March issue of the American Journal of Psychiatry and are based on two studies funded by the federal government's National Institute on Drug Abuse.
Methamphetamine can be smoked, snorted, injected, or taken by mouth. On the street, it goes by several names: speed, meth, and chalk -- and in its smoked form, ice, crystal, and glass.
The researchers looked specifically at former meth users. What they found was that the drug causes profound, long-lasting changes in brain chemistry that can lead to problems with short-term memory, as well as to coordination disturbances similar, although not as severe, as that seen in Parkinson's disease.
In the first study, investigators from the Brookhaven National Laboratory in Upton, N.Y., compared a group of former meth users with a healthy, nondrug-using control group. They found that members of the ex-methamphetamine group still had an abnormality in their brain's dopamine system, specifically in the part involved in recycling dopamine within the brain.
Dopamine -- one of a group of chemicals that allow brain cells to communicate with each other -- is involved in a host of functions controlled by the brain, among them movement and mood. Dopamine also is the brain's "feel good" chemical, and it is an effort to stimulate that function which makes people abuse drugs in the first place.
The second study, conducted by the same group, found that methamphetamine dramatically increases brain metabolism in several areas. Not in a good way, researchers say, since the overactivity could be a sign of inflammation or a response to damage.
The effect was most powerful in a region of the brain called the parietal cortex -- which is involved in sensation and perception of space and dimension. It's an important finding because in animal studies, the parietal cortex is exactly the area found to be most sensitive to methamphetamine damage.
At the same time, researchers note that the drug use causes metabolism to slow down in other parts of the brain -- another feature seen in patients with Parkinson's disease.
Even more ominous: Three of the people examined in these studies had been off methamphetamine for 11 months or more -- but the researchers could find no evidence that this long period of abstinence had resulted in any recovery from the drug-induced brain damage.
In fact, lead researcher Nora D. Volkow, MD, tells WebMD she plans to follow those who participated in this study to see whether there is ever a point at which detoxification can reverse the damage.