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