I SMELL A RAT

Should we take seriously the new scientific "findings" that pot is as
addictive as heroin?

By Phillip O. Coffin

The National Institute on Drug Abuse concludes every press release
on its Web site with the boast that NIDA supports more than 85 percent of
the world's research on the health aspects of drug abuse and addiction, and
publicizes the results of that research.

That the government's drug warriors are the customers for most
health studies on drug abuse and that they aggressively peddle these
studies doesn't make the studies automatically suspect. In fact, the
science behind NIDAfunded studies is reputable 99.99 percent of the time.
But what is suspect is the spin NIDA routinely applies to its sponsored
studies, such as the successful flackery that accompanied the marijuana
study that appeared in the June 27 edition of Science.

The authors of the Science paper"Activation of
CorticotropinReleasing Factor in the Limbic System During Cannabinoid
Withdrawal" suggest in their conclusion that marijuana may be as
addictive as heroin and cocaine, and that pot's "subtle disruption" of
brain chemistry may leave users " 'primed' for further disruption by other
drugs of abuse."

Both the New York Times and the Washington Post published pieces
based on the NIDAsponsored study. The first sentence of the Times story is
indistinguishable from that of the NIDA press release.

The Times: "People who regularly smoke large amounts of marijuana
may experience changes in their brain chemistry that are identical to
changes seen in the brains of people who abuse heroin, cocaine,
amphetamines, nicotine and alcohol, scientists have found."

NIDA: "Longterm use of marijuana produces changes in the brain
that are similar to those seen after long term use of other major drugs of
abuse such as cocaine, heroin, and alcohol."

Although the Post's lead was more original, it, too, followed the
NIDA line. "Marijuana may be a far more insidious drug than generally
thought," the Post reported, "and apparently alters the brain chemistry of
pot smokers in ways that may make them particularly vulnerable to 'hard'
drugs such as heroin or cocaine, two independent research groups have
found."

How seriously should we take these findings? In one study,
researchers injected rats with cannabinoids chemicals that act like THC,
the main active ingredient in marijuana for weeks, habituating them to
the compounds. Because cannabinoids can linger in the system for some time,
few marijuana users experience anything approximating physical withdrawal
if they stop smoking. To mimic coldturkey withdrawal, the researchers then
injected these habituated rats with a drug that "blocks" the effects of all
cannabinoids.

Following the injection of the blocker, the researchers observed an
increase of the brain chemical CRF in the amygdala, a portion of the brain
involved with the emotions of fear and aggression. The presence of CRF in
the amygdala is associated with stress and anxiety. Withdrawal from heroin,
cocaine, and alcohol also increases CRF in the amygdala. The authors of the
paper lean on these findings to suggest that marijuana acts on the brain as
other drugs of abuse do, and that users who stop smoking marijuana might
indulge in heroin, cocaine, or alcohol to stave off the unpleasantness of
increased CRF in the amygdala.

A second marijuana study (not financed by NIDA) that also appeared
in the June 27 Science, and which was also mentioned in the Times and Post
articles, further investigates the effects of cannabinoids on rats. The
study found an increase of the neurotransmitter dopamine in rats' nucleus
accumbens often termed "the pleasure center of the brain" following
several cannabinoid injections. Most recreational drugs, like heroin,
cocaine, alcohol, and nicotine, increase dopamine in the accumbens. While
recognizing that other researchers have tried and failed to induce an
increase of dopamine in the accumbens by injecting cannabinoids, the
authors use their results to suggest that marijuana is more like heroin and
cocaine than was previously thought.

Before going any further, consider two points. First, injected
cannabinoids may not mirror the effects of smoked marijuana. There are
several other chemicals in marijuana that may modify the effects of THC
alone, and smoking a drug is a different experience from injecting it.
(Imagine the difference between smoking a cigarette and injecting pure
nicotine directly into a vein.)

Second, rats are not humans. This does not mean cannabinoid
research on rodents is worthless. But there are several pharmacological and
social differences that reduce the relevance of rat research to social
policy. And since the pleasure derived from smoking marijuana is a core
issue, consider a third point: Rats don't like pot.

I know this firsthand from my own research on cannabinoids and
rats. Initially, I felt guilty about drugging rats and then killing them
for the necessary dissection. "At least they're getting stoned first," I
rationalized. Then I realized that being stoned means very different things
to rats and humans. Marijuana makes rats slothful, and they excrete all
over themselves. Before the injection they're quite friendlythese are lab
animals, remember, not hardened street rats. After the injection they
honestly seem rather depressed.

Another fun fact about rats and pot is that rats won't
selfadminister any cannabinoid. When given the choice of receiving an
injection of THC or a placebo, rats consistently choose the placebo. And
when given the choice between a placebo and the cannabinoid blocker, rats
choose the blocker. Tens of millions of humans, as we know, willingly
partake of marijuana, and these differences between rat and human behavior
should discourage us from using two rat studies to assert that a) marijuana
is addictive in the same way as harder drugs are and b) marijuana primes
humans for addiction to harder drugs.

The Science studies also ignore simple truths about brain
chemistry. Consider that sex causes dramatic increases in dopamine.
Laughter, too, increases dopamine. The syllogism that dopamine equals
pleasure and pleasure leads to addiction just doesn't apply directly to
human behavior. How seriously would anyone take a researcher who suggested
that laughter could lead to drugs and deadly addictions?

And the CRFproducing process associated by the researchers with
marijuana withdrawal is not unique to drugs. Just as sex increases dopamine
in the accumbens, stubbing one's toe may ignite neurological anxiety.
Indeed, chronic toestubbing can lead to the abuse of analgesics like
aspirin. Again, the science reported in Science is reputable. It's just
taken out of context.

Also lost in the mix is that fact that other published NIDAfunded
and non NIDAfunded studies have found that cannabinoids don't increase
dopamine in the accumbens. Still other researchers have shown that monkeys
don't like the effects of cannabinoids any more than rats do. But findings
like these that don't support the government's drug agenda are rarely
catapulted into the news by the publicity machine.

So let's set aside for a moment the drug preferences and
predilections and propensities of rats and turn our attention back to
humans. Of the estimated 70 million Americans who have tried marijuana,
only 1 percent have gone on to heavy cocaine use. Perhaps NIDA and the
pliant journalists should inject themselves with a big dose of common
sense.

Phillip O. Coffin is a research associate at the Lindesmith Center, a
drugpolicy think tank.