NEW YORK, Mar 02 (Reuters Health) - Methamphetamine, a highly addictive drug abused by millions in the US, causes more damage to the brain than heroin, alcohol or cocaine, scientists said Thursday.

The drug--commonly known as "speed," "meth" and "chalk" or in its smoked form as "ice," "crystal," "crank" and "glass"--can be made from cheap over-the-counter ingredients, which has fueled its growing popularity.

But researchers from the Brookhaven National Laboratories in Upton, New York and elsewhere warn in the March issue of the American Journal of Psychiatry that users suffer memory and coordination deficits that last up to 11 months after they stop using the drug.

Their findings "underscore the serious nature of methamphetamine abuse and emphasize the need to alert users and potential users to the long-lasting, profound effects of this drug," Dr. Alan I. Leshner, director of the National Institute on Drug Abuse (NIDA), said in a statement.

Dr. Nora D. Volkow and colleagues studied brain scans from 15 former methamphetamine abusers, and compared them with 18 non-users. The investigators measured molecules called dopamine transporters, which are involved in regulating brain signals such as feelings of satisfaction and pleasure.

The methamphetamine abusers had reduced levels of dopamine transporters in two areas of the brain, the authors note in their report. These reduced levels were associated with impaired memory and motor skills, even in people who stopped taking the drug up to 11 months earlier.

"This is objective evidence that methamphetamine is damaging to the brain. These changes are much greater than what we have seen with heroin, alcohol, or cocaine," said Volkow in a prepared statement. "We need to further study whether these changes are long-lasting and result in long-term impairment of memory and motor functions, such as speed and motor coordination."

In a second study, the investigators measured brain metabolism in 15 former methamphetamine abusers and found that this group had 14% higher metabolic rates than 21 comparison non-users.

"The increased metabolism we saw is consistent with an inflammatory response," Volkow explained in a statement. "This result, taken together with our other findings, indicates that this is a very toxic drug."

Methamphetamine was developed early in this century from amphetamine, and was used originally in nasal decongestants and inhalers. Like amphetamine, it can give users more energy, decreased appetite and a general sense of well-being for up to 8 hours. The initial "rush" is often followed by agitation that can lead to violent behavior, according to NIDA.

The drug has long been a major problem in San Diego, California, but its use has started spreading through the West and Southwest of the US, including rural areas, the NIDA reports.

A 1996 survey estimated that 4.9 million people in the US had tried methamphetamine at some time in their lives. In 1994, the estimate had been just 3.8 million.

• More news on Drug Abuse

Related MEDLINEplus Pages:

• Drug Abuse