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What Street Drugs Do to Your Brain
“George,”
is 17, tall, good looking, quiet - and a prime example of how much kids
do and don’t know about how illegal drugs act on the brain. The
son of a friend of mine, George knows a lot –and I mean, a LOT –
about drugs. Asked what he takes, he rattles
off pot, alcohol and
‘shrooms (mushrooms), which he and a friend grow.
But he’s also done acid (LSD), crack (cocaine), crystal meth (a
form of methamphetamine), prescription tranquilizers and painkillers
such as Valium and Percocet, and, oh, yeah, GHB, Ecstasy (and its
variants) and mescaline. He
learned to “cook” meth using ingredients like decongestants, brake
cleaner and road flares (for the phosphorus) in the bathroom at one
expensive residential treatment facility. Asked if he wants to get
clean, he says, “Not right now. My use is just recreational.” And
perhaps it is. But the latest government figures, released in September,
show that illegal drug use is up among young adults between 18 and 25.
And there’s obviously that lot that George, and America’s other 16
million illicit drug users, may not
know about how street drugs affect the brain. So,
here goes: One main class of street drugs is the psychostimulants, which
include amphetamines (including, methamphetamines, and MDMA (Ecstasy) )
and methylphenidate
and cocaine. In low doses,
amphetamines generate feelings of euphoria and
alertness. But at higher doses, these drugs can trigger paranoia
and psychosis. Amphetamines
are both psychologically and physically addicting. Also called
“speed,” they can increase blood pressure and heart rate..
Because they also constrict blood vessels, they “deprive the heart of
blood flow while forcing it to do more work,” says
psychopharmacologist Glen Hanson, acting director of the National
Institute on Drug Abuse. In
the brain, Hanson says, amphetamines and methamphetamines act as
“releasers” of neurotransmitters, forcing the brain to pump out 30 to 40 times the normal levels of these
neurotransmitters, most notably dopamine, serotonin and norepinephrine. The
immediate effect is to activate the brain’s
“reward” circuits. But
over-revving this circuitry can also cause violent behavior.
Chronic stimulation depletes
brain cells so that they
can no longer produce neurotransmitters. By
contrast, MDMA, or Ecstasy, now used by nearly a million people,
according to federal figures, works somewhat differently.
As one might guess from its chemical name
(3,4-methylenedioxymethamphetamine), MDMA is an amphetamine. . Until
recently, scientists thought that MDMA worked primarily on serotonin,
creating such a flood of good feeling that users called it the “love
drug.” In
one set of studies, Dr. Una
D. McCann, associate professor of psychiatry and behavior sciences at
Johns Hopkins School of Medicine and her husband, Dr. George A. Ricuarte,
associate professor of neurology, also at Johns Hopkins, examined
monkeys, baboons and humans and found that MDMA is
toxic to neurons that make serotonin. In
humans, McCann and Ricuarte have documented damage using both PET scans,
a brain imaging technique, and tests for 5-HIAA, a breakdown product of
serotonin. The implications
are serious –
without sufficient serotonin, sleep, mood, memory and other crucial
brain functions may be
disrupted. Indeed,
MDMA users, George among them, often
report that depression (or “E-pression”) strikes after a weekend on
Ecstasy. MDMA can also induce muscle tension and an unpleasant,
involuntary clenching of teeth, notes Dr. Patrick E. McKinney, an
emergency room physician and medical director of the New Mexico Poison
and Drug Information Center in Albuquerque.
MDMA can also trigger such high body temperatures– 107 to 108
degrees Fahrenheit – that seizures, multi-organ failure and even death
can result. Recently,
in a paper in Science, Ricuarte’s group showed that in animals,
Ecstasy lowers levels of dopamine as well as serotonin, raising the risk
of Parkinson’s disease. So far, however, there appear to be no
increased rates of Parkinson’s disease among human Ecstasy users. In
fairness, it’s also true that the benefits of Ecstasy are beginning to
be taken seriously as well. Last fall, the US Food and Drug
Administration approved a study of Ecstasy as an aid to psychotherapy. Cocaine,
a psychostimulant, works in
yet a different way, notes
Dr. Marc Kaufman, a research pharmacologist at McLean Hospital in
Belmont. It
does cocaine rev up the brain’s “reward” circuitry.. But unlike
other drugs, cocaine does its
damage not by directly damaging neurons
that make neurotransmitters but by reducing blood flow to parts of the brain. By causing blood vessels to narrow, it raises
the risk of stroke and
heart attack. Using
MRI scans of the brain, Kaufman and others have also shown that women
are somewhat protected against cocaine damage, because estrogen
helps keep blood vessels open. . Some
of the most popular street drugs
are depressants, among them, the “date rape” drugs. One
such “downer” is GHB, technically called gamma hydroxybutyrate but
also known as “liquid ecstasy” or “Georgia HomeBoy.” It can be
easily slipped into a person’s drink. Like
alcohol and the tranquilizer Valium, GHB, acts through so-called GABA
receptors, the brain’s intrinsic tranquilizer system; when GABA
receptors are activated, neural activity slows down. So
far, GHB has not been shown to cause damage to neurons. But it can relax
a user too far – to the point of rendering someone incapable of
resisting unwanted sex. It can also lead to coma and even to death;
alcohol can enhance this effect. Another
date-rape drug, Rohypnol, has similar effects. Dubbed “Roofies,”
rohynpol is a benzodiazepine. Like GHB, it works through GABA receptors
and receptors for benzodiazepine as well. Rohypnol, which is legally
available overseas, can also trigger amnesia, making it
treacherousin the hands of anyone seeking to coerce someone into
sex and render his victim unable to recall events. Ketamine,
a powerful anesthesia drug often used by veterinarians, is another
popular downer. Dubbed
“K” and “Special K,” it
is similar to PCP ( “phencyclidine, or angel dust” )
and is easy to make.
It acts by blocking NDMA
receptors in the brain, producing general anesthesia. Technically,
ketamine is a “dissociative anesthetic,” meaning it does not
directly kill pain but makes people not react to the pain they are
feeling. By
contrast, heroin is a direct painkiller, acting on opiate receptors
in the brain. It is so addictive that users who are hooked must
have heroin, or its legal substitute, methadone, every day simply in
order not to feel sick. The
list of abusable drugs – including alcohol, LSD and mescaline - is
endless, but we have to stop somewhere, so we’ll end with marijuana, a
sedative and a light hallucinogen. Marijuana
acts on cannabinoid receptors and is not believed to cause permanent
brain damage The
bottom line with all drugs of abuse, adds Hanson, it that recreational
use can turn into a “game of Russian Roulette.” Street drugs
“don’t kill everyone who takes them,” And obviously not everyone
becomes addicted. But he adds, “The
benefits just do not warrant the kind of risk you are exposing yourself
to." George,
among others, is not convinced. “I think it all comes down to the
person. We are all different, with such different brain chemistry,” he
says.
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