Your Health
Marijuana as medicine How strong is the science?

Should marijuana be used as a medicine, as its advocates say? Or is it a
dangerous drug of abuse that exposes users to brain damage and lung cancer?

Last fall, voters in California and Arizona approved laws allowing
patients to smoke marijuana for medical purposes with a doctor's
recommendation. Other states are considering similar moves. And the
influential New England Journal of Medicine has editorialized in favor of
extending this policy nationwide.

Federal health and drugenforcement officials have reacted strongly to
these initiatives. "Seeming to legalize marijuana for anything would give
young people the wrong impression," says Sheryl Massaro, spokeswoman for the
National Institute on Drug Abuse. "That doesn't even seem to enter the
minds of a lot of people who are promoting it for medical use."

The debate over medical marijuana seems likely to continue for some time,
caught up as it is in the larger question of how the nation should deal
with recreational drug use and abuse. "It's a shame" that the debate is so
polarized, says Harrison Pope, a Harvard University psychiatrist who
studies marijuana. "Science should know more about this substance by now,
considering how long it has been in use."

While the debate continues, here is what is known about the health
effects both good and ill of this controversial drug.

The harm it can cause

When it comes to the possible ill effects of chronic marijuana use, the
Federal Government has willingly funded studie and even provided
government grown marijuana. The possible damage falls into two
categories.

Effects on the brain. Perhaps no aspect of marijuana use has been so
thoroughly studied. Researchers have established what many users know:
Marijuana's effects on coordination and shortterm memory make it
inadvisable to drive, operate heavy machinery, or try to learn anything
important while under the drug's influence.

The biochemical explanation for this may have come in 1988, when
scientists found receptors for THC, a marijuana component, in the parts of
the brain controlling memory, mood, visual processing, attentiveness, and
the ability to filter out extraneous stimuli. The discovery also clarified
why it's impossible to take a fatal dose of marijuana: There are hardly any
THC receptors in the areas of the brain that control basic life functions,
such as consciousness and respiration. As for longterm effects of
potsmoking, the results are not clear.

Researchers daily users, after several days of abstinence, continue to
show subtle but measurable cognitive impairments. But it's not clear
whether this afterthefact impairment results from changes in the brain or
is just a slow, continuous release of marijuana constituents that have been
stored in the brain and fatty tissues.

"Of the three studies of this question that have been done, the results
show no, mild, and fairly pronounced longterm damage," says Pope. "So the
jury is still completely split. "

Also uncertain is whether marijuana produces any withdrawal symptoms the
way heroin, cocaine, alcohol, and nicotine do. The most that researchers
have been able to discern are occasional cases of mild and shortlived
anxiety and insomnia upon abrupt cessation after years of heavy use.

Respiratory damage. For 15 years, Donald P. Tashkin and colleagues at
the University of CaliforniaLos Angeles have probed the respiratory systems
of hundreds of longterm, heavy marijuana smokers. Their conclusion: Puff for
puff, smoking marijuana is even harder on the lungs than smoking tobacco.

"Smokers of marijuana had as frequent symptoms of chronic bronchitis as
smokers of tobacco, despite the fact that the tobacco smokers smoked more
than 20 cigarettes a day, compared with the 3 to 5 joints a day used by
the marijuana smokers," Tashkin says.

Marijuana smokers also had more microscopic damage to the lungs' system
of defense against inhaled contaminants and microbes, as well as more
precancerous cellular changes.

An analysis of marijuana smoke shows why this is so: It has 50 to 70
percent more known carcinogens than tobacco smoke. And since marijuana
joints don't have filters and are usually smoked down to the last fraction
of an inch, they deliver more irritating particulates to the lungs.
Recreational users further magnify the damage by inhaling the smoke deeply
and holding it in as long as possible.

But does smoking marijuana actually cause cancer? It's too soon to tell.
"It's unusual to develop lung or upper airway cancer under the age of 40,
but after 50 it occurs with increasing frequency," Tashkin points out.
"The current marijuana epidemic began in the late 1960s, and the bulk of the
smokers are just now reaching the age of 50. So we're just approaching the
cusp of our ability to show an association between marijuana smoking and
these cancers." It's also unknown whether the risk of cancer would
gradually decline after a person stopped smoking marijuana, as it does with
tobacco.

The good it can do

Less is known about marijuana's beneficial side. For the past decade, the
Government has refused to provide either money or marijuana to researchers
studying the drug's potential therapeutic effects, so this research has
been nearly at a standstill. Early this year, however, in response to the
Arizona and California initiatives, the National Institutes of Health
called together an expert panel to consider possible areas of research. The
panel concluded that there's' enough evidence of smoked marijuana's
usefulness to justify resuming studies.

Researchers are interested in three major areas where smoked marijuana
seems to work therapeutically:

Nausea from chemotherapy. Because it's illegal, there are no figures
available on how many cancer patients selftreat their nausea with smoked
marijuana. But a 1991 survey of more than a thousand cancer specialists
found that 44 percent had recommended it to at least one patient, and that
48 percent would prescribe it if it were legal.

Before the Federal Government cracked down on research, enough had been
learned to persuade the U.S. Food and Drug Administration to approve, in
1986, the marketing of dronabinol (Marinol). This drug, in pill form,
contains THC to treat nausea caused by cancer chemotherapy.

With a legal synthetic marijuana pill already available, why are people
still pushing for the right to smoke marijuana for medical purposes?
Because patients and doctors assert that the two do not behave the same in
the body. And a convincing body of research, some of it now nearly two
decades old, shows that smoked marijuana suppresses nausea better than
Marinol pills, and with fewer side effects.

Physicians speculate that one reason for the difference is that smoked
marijuana enters the bloodstream almost instantaneously, allowing patients
to control their dose, whereas the oral version is absorbed slowly for
some time. In addition, there's the possibility that the complex mix of
compounds in whole, smoked marijuana somehow counteracts the more unpleasant
effects of pure THC, such as extreme dizziness and unsteady gait.

Some people maintain that newer antinausea medications have made both
Marinol and marijuana unnecessary.

"The American Medical Association and so forth, they're not clamoring for
medical marijuana, and I think for good reasons," says Billy R. Martin,
professor of pharmacology at the Medical College of Virginia and a longtime
researcher on the metabolism of marijuana. "There are better drugs out
there." One often cited as such is the antinausea drug ondansetron
(Zofran).

But even the newest drugs do not work for everyone a fact that has led
some patients to continue using marijuana.

AIDS wasting syndrome. Marinol has, in limited clinical trials, proved
an effective treatment for wasting syndrome, the deadly loss of appetite
and consequent extreme weight loss that afflicts many AIDS victims in the end
stages of the disease. In fact, Marinol is one of only three FDAapproved
treatments for this condition (the others are human growth hormone and a
hormone called Megace, or megestrol acetate).

But some AIDS patients say it's not an adequate substitute for marijuana.
"All it did was make me very groggy without enhancing my appetite," one
said.

AIDS activists and the doctors who treat the disease report that
marijuana is also useful for suppressing the nausea that's a side effect of
several effective anti AIDS drugs.

Advocates of providing AIDS patients with marijuana acknowledge the risks
of the drug to lung and brain, but point out that these longterm effects
matter little to someone with a terminal illness.

However, there's no firm evidence that marijuana is effective against the
wasting syndrome; that has never been tested in clinical trials. Donald I.
Abrams, an AIDS specialist at the University of CaliforniaSan Francisco,
has been trying since 1993 to secure Government permission to compare
smoked marijuana to Marinol pills.

Abrams also hopes to assess marijuana's effect on the immune system. Many
years of research have produced conflicting results, with some studies
showing that marijuana depresses certain components of the immune system and
others showing either no suppression or, occasionally, stimulation. However,
a long term study of 1500 HIVpositive men who used marijuana found the
drug use didn't seem to accelerate the deterioration of their immune systems.

Spasticity. People with spinal cord injuries and multiple sclerosis are
prone to painful muscle spasms and tremors; existing drugs give only
partial relief, with severe side effects.

There are many anecdotal reports that smoked marijuana relieves those
symptoms but, to date, no largescale, controlled clinical trial has
compared marijuana with existing legal drugs.

"With smoked marijuana, patients get immediate relief, whereas with the
oral drug they get a delayed, big rush of unpleasantness. When they take a
smaller dose, it doesn't work," says Paul Consroe, a University of Arizona
pharmacology professor, who is studying the effect of marijuana on muscle
spasticity.

Researchers seem to have lost interest in one oncepromising use of
marijuana to treat glaucoma. They discovered early on that marijuana
reduced the intraocular pressure resulting from this potentially blinding
disease. However, the treatment never caught on with more than a handful of
patients; to keep pressure down, marijuana must be taken every two to four
hours, and patients didn't like being high continuously. Also, many new
drugs work well, with minimal side effects.

Recommendations

The evidence is convincing that longterm regular use of marijuana
exposes users to significant risk of lung damage; many may also suffer
subtle but measurable cognitive and motor impairments that persist for weeks
after use stops. And, of course, nonmedical use of marijuana is illegal
everywhere. However, compared with other drugs of abuse such as tobacco,
alcohol, and cocaine, marijuana is much less addictive if at all and
there's no danger of death from an overdose.

A number of attempts have failed to isolate compounds from marijuana that
would achieve the desired therapeutic effects without making patients high.
"It seems that the same neurological receptor controls all the effects, the
good and the bad," says Consroe.

Since an unknown but probably substantial number of people are smoking
marijuana with the expectation that it will help make their AIDS or
terminal cancer more tolerable, CONSUMER REPORTS urges the Federal
Government to permit further research in this area to better determine the
drug's efficacy and side effects.

In the meantime, CONSUMER REPORTS believes that, for patients with
advanced AIDS and terminal cancer, the apparent benefits some derive from
smoking marijuana outweigh any substantiated or even suspected risks. In the
same spirit the FDA uses to hasten the approval of cancer drugs, Federal laws
should be relaxed in favor of states' rights to allow physicians to
administer marijuana to their patients on a caring and compassionate
basis.

One of the best first sources to read on drug policy is still the 1972
clasic "Licit & Illicit Drugs", from the editors of Consumer Reports.