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'Speed' May Cause Long-Term Damage to the Brain

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WebMD Health News

March 27, 2000 (Atlanta) -- Whether you call it meth, speed, crank, crystal, glass, chalk, or ice doesn't matter. Whether you ever took it does, because studies published in Monday's issue of the journal Neurology find evidence of long-term brain damage in users of the increasingly popular street drug methamphetamine.

Using a type of imaging that detects healthy brain cells, Thomas Ernst, PhD, and colleagues at Harbor-UCLA Medical Center found that up to 6% of neurons in important areas of the brain are missing in former methamphetamine users enrolled in recovery programs. Whether this damage ever can be repaired is unknown; it lasted for as long as 21 months after the last time study patients used the drug.

"We know from studies in non-humans -- rats, baboons, etc. -- that methamphetamine is [toxic to the nerve endings of brain cells]," Ernst tells WebMD. "We might be observing this effect."

Subjects included 26 recovered methamphetamine users and 24 healthy subjects. The users had a history of heavy methamphetamine use -- at least a half gram a day for at least 12 months, taken by "snorting" the powdered form of the drug into the nose or by smoking the crystallized form known as ice. Only three of the subjects also took the drug by injection. None of the subjects were addicted to alcohol or other drugs, and they all subjects tested negative on urine tests for illicit drugs.

Ernst and his colleagues speculate that the types of brain loss seen in the patients might explain why many users have long-lasting behavioral defects such as violence, psychosis, and personality defects. These defects can last for years after the last time the drug was used.

The researchers currently are conducting tests of former methamphetamine users to see whether the damage they detected has caused any loss of brain function. "We have ongoing studies which evaluate [recovering methamphetamine users] for possible [memory, thinking, or sensory] deficits and slowing in motor function," Ernst says. "We [also] have an ongoing study, funded by the National Institute on Drug Abuse, to specifically evaluate methamphetamine users who are enrolled in drug rehabilitation programs during the length of their treatment in order to study whether any improvement in brain chemistry can be observed. ... We cannot answer this question yet."

Methamphetamine damage may not occur in patients who receive the drug in the small doses used to treat hyperactivity disorders in children or sleep disorders in adults. This is because lower doses of the drug may have an opposite effect than those seen with the large doses taken for recreational effects.

Rat studies by neurobiologist Wayne A. Cass, PhD, at the University of Kentucky in Lexington, show that methamphetamine does not necessarily kill brain cells, but instead damages them so that they stop working. Recent studies show that the rats' damaged cells can get better over time, and the rats eventually recover from toxic doses of methamphetamine.

In an interview with WebMD, Cass says that his rat model may not duplicate the effects of long-term methamphetamine use in humans, as the drug damages the rat brain after only one day of heavy exposure. Even so, his findings are not good news for former users of the drug. "Even though it took the rats only a year to recover, that is a third of their life," Cass points out. "Even if this recovery happens in humans it could take a long time, and whether humans could recover as well as rats is unknown."

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