Pubdate: Thu, 09 Mar 2000
Source: News Watch (US Web)
Copyright: 2000
Author: Maia Szalavitz,  Maia Szalavitz is a contributing editor to NewsWatch


Are the media so keen to push anti-drug news that they're prepared to
sacrifice scientific credibility?

More evidence that reporters spotlight stories which reflect the prevailing
biases: Of three recent studies on marijuana, the American media focused
most heavily on the one that showed negative effects, while the British
media gave greater weight to the two which found the drug's actions to have
positive results.

The U.S. is currently heavily committed to a "war on drugs" position, while
the U.K., like most of Europe, has begun to seriously debate cannabis
decriminalization and other "softer" measures to reduce drug-related harm.

Though the fact that the two positive studies were conducted (a) in
European countries and (b) on animals may partially account for American
reporters' downplaying of them, the American study was covered by almost
all of our major media despite not yet having been published in a
peer-reviewed journal.

Coverage of the other two was spotty in the U.S. - but made most of the
major U.K. papers and the BBC. The negative study received twice as much
coverage by major American papers and networks as each positive study did.
On the other side of the Atlantic, the ratio was almost reversed: Only the
BBC, an Irish newspaper and the Daily Mail covered the negative, American
story and the BBC actually mentioned the positive studies in its story.

Of course, the fact that the negative story was presented by a researcher
from Harvard University at the American Heart Association meeting does
offer prestige and news value.

But the British media may have been right to ignore it, because the study
itself doesn't say much that can be considered important.

The study reported an association between marijuana and heart attacks and
is the first study to document such an association. According to Dr. Marvin
Mittleman of the Harvard School of Public Health, a person's heart attack
risk quintuples for the hour after smoking a joint, and then returns to
normal within two hours.

However, despite the fact that being the first to discover something often
means 'news' to reporters, to scientists it means that the results should
be considered preliminary until they are replicated. When dealing with a
drug like marijuana, which has been demonized by the government, the fact
that these effects are being seen for the first time should be cause for
skepticism, rather than cries of "At last!" Tobacco researchers, for
example, didn't have to look far before uncovering hundreds of major
negative effects of that drug, and there has been a comparable amount of
study into the effects of marijuana.

Also, the new study could not determine whether this heart attack risk
could actually lead to increased mortality - and in fact, several
epidemiological studies suggest that it doesn't. The most important was a
study of over 65,000 patients aged 15-49 in the Kaiser Permenente Medical
Care Program in northern California, which was published in the American
Journal of Public Health in April, 1997. It showed no increased risk of
death among current marijuana users compared to either non-users or those
who had ever tried pot in the past.

The new study also could not provide information on whether marijuana
caused the heart attacks - all it found was that out of 3,882 heart attack
victims, 3 percent smoked pot and, of this group, 37 percent had smoked pot
within a day of their heart attacks.

No information was given as to whether the marijuana smokers also smoked
cigarettes or how frequently they smoked pot - either of which could affect
the results.

There was no information on whether they had had sex after smoking pot or
engaged in other strenuous activities which might independently increase risk.

To pump up the media value of the study, Mittleman suggested that pot
smoking could become a significant source of cardiac mortality as boomers
age: "Many of these people were users of marijuana when they were in their
teens and 20s, and a sizable percentage of them may still use the drug,
either frequently or occasionally," he said in a press release.

However, statistics from the Substance Abuse and Mental Health Services
Association belie this notion.

While about 50 percent of people between 40 and 50 years report having
tried marijuana, less than 4 percent typically respond that they've smoked
it in the past month.

And while a five-times-greater heart attack risk sounds scary, for an
otherwise healthy 50-year-old man this amounts to a one in 100,000 chance
of having a heart attack during any particular pot-smoking session. This is
less than the risk a couch potato faces when starting to exercise
vigorously - but twice the risk a healthy person that age would face when
having sex or exercising.

The two studies largely ignored by the U.S. media looked at the impact of
marijuana and marijuana-like substances on brain cancer and multiple
sclerosis (M.S.). The M.S. study, which was published in the prestigious
journal Nature, found that cannabinoids (the active ingredients in
marijuana and marijuana-like synthetics) have a significant impact on
tremors and spasticity in mice with a disease used to model human M.S.

These effects were particularly potent early in the disease - and backed
the claims of people with M.S. who have long said that cannabis is helpful
to them. (M.S. is a chronic and often severely debilitating disease
affecting thousands of Americans for which there are few effective
treatments and no cure.)

The brain cancer study, published in Nature Medicine, found that THC, the
main psychoactive ingredient in pot, helped eliminate or reduce a currently
incurable form of brain cancer in rats. The researchers plan human tests -
though some cancer doctors are skeptical, claiming that the rat model isn't
precisely transferable to humans and that the study couldn't determine
whether the THC or the liquid used to infuse it into the brain caused the

Whatever the flaws and merits of these various studies, journalists and
editors should constantly examine their own biases when they decide which
to cover and which to ignore.

They should also question research methodology and become familiar with the
literature in the area that they cover.

Without context, a report on a single study can be highly misleading.

Maia Szalavitz is a contributing editor to NewsWatch

Maia Szalavitz  212-879-2305
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