"While the meth users in this study hadn't used the drug for some time anywhere from two weeks to 21 months, this research strongly suggests that methamphetamine abuse causes harmful physical changes in the brain that can last for many months and perhaps longer after drug use has stopped," said Dr. Alan I. Leshner, Director, National Institute on Drug Abuse (NIDA).
In their study, Dr. Linda Chang and Dr. Thomas Ernst measured levels of brain chemicals that indicate whether brain cells are healthy or are diseased or damaged.
"We found abnormal brain chemistry in the methamphetamine users in all three brain regions we studied. In one of the regions, the amount of damage is also related to the history of drug use those who had used the most methamphetamine had the strongest indications of cell damage," Dr. Chang said.
The researchers found that levels of one chemical marker, N-acetyl-aspartate, were reduced by at least five percent in the methamphetamine abusers. "Many diseases associated with brain cell loss or damage, such as Alzheimer's disease, stroke, and epilepsy, are also associated with reduced N-acetyl-aspartate," said Dr. Ernst. "Reduced concentrations of N-acetyl-aspartate in the drug users' brains suggest that long-term methamphetamine abuse results in loss or damage to neurons, the cells we use in thinking." Two other chemical markers, myo-inositol and choline-containing compounds, are associated with glial cells, which act to support neurons. "Methamphetamine abusers showed increases of 11 percent and 13 percent in levels of these markers compared with normal individuals," Dr. Ernst said. "This suggests an increased number or size of glial cells as a reaction to the injurious effects of methamphetamine."
The researchers, who received funding from NIDA, plan to conduct more extensive studies to determine if these brain changes caused by methamphetamine abuse might be reversed or corrected by treatment.
The National Institute on Drug Abuse is a component of the National Institutes of Health, U.S. Department of Health and Human Services. NIDA supports more than 85 percent of the world's research on the health aspects of drug abuse and addiction. The Institute carries out a large variety of programs to ensure the rapid dissemination of research information and its implementation in policy and practice. Fact sheets on the health effects of drugs of abuse and other topics can be ordered free of charge in English and Spanish by calling NIDA Infofax at 1-888-NIH-NIDA (644-6432) or 1-888-TTY-NIDA (889-6432) for the deaf. These fact sheets and further information on NIDA research and other activities can be found on the NIDA home page at http://www.drugabuse.gov.