THE RETURN OF REEFER MADNESS

The U.S. drug czar's office is running ads implying that smoking
marijuana can lead to insanity. But pushing dubious science is no way
to convince teenagers not to do drugs.

Parents who read the New York Times or Newsweek this past summer could
be forgiven for freaking out when they came across a full-page ad
warning them about the effects of marijuana on their teenagers. If the
kids were off somewhere sparking up a joint, the federally funded
message seemed to say, they were at risk for severe mental illness.
Were those parents hallucinating, or was Reefer Madness, long since
debunked, suddenly a real problem to be reckoned with?

The latest salvo in the never-ending war on drugs, the ads, which also
ran in magazines like the Nation and the National Review, bore a stark
warning. Under the headline "Marijuana and Your Teen's Mental Health,"
the bold-faced subhead announced: "Depression. Suicidal Thoughts.
Schizophrenia."

"If you have outdated perceptions about marijuana, you might be
putting your teen at risk," the text went on. It warned that "young
people who use marijuana weekly have double the risk of depression
later in life" and that "marijuana use in some teens has been linked
to increased risk for schizophrenia." It followed with the sneering
question, "Still think marijuana's no big deal?"

The rhetoric is alarming. But the research data used to support the ad
campaign is hazy at best. Though carefully worded, the campaign blurs
the key scientific distinction between correlation and causation. The
ad uses some correlations between marijuana use and mental illness to
imply that the drug can cause madness and depression. Yet these
conclusions are unproven by current research. And several leading
researchers are highly skeptical of them.

Scare tactics in the war on drugs have been around at least as long as
Harry J. Anslinger, the federal drug warrior of the 1930s famed for
his ludicrous pronouncements about the dangers of marijuana. But
they're widely regarded as ineffective in deterring teen drug use. In
fact, some research suggests they may actually increase
experimentation. If anything, experts say, the latest ad campaign's
overblown claims could damage credibility with teens, undermining
warnings about other, more dangerous illicit substances. With medical
marijuana a matter of renewed national debate, and with evidence
emerging that there may be no connection between marijuana and lung
cancer -- a key strike against the drug's use in the past -- the
government's new campaign smacks more of desperation than science.

Spearheaded by the Office of National Drug Control Policy, better known as
the "drug czar's" office, the ad campaign ran in print during May and June;
it continues today on the federal government's Web site, Parents: The
Anti-drug ( http://www.theantidrug.com/drug_info/mjmh_overview.asp ). There are plans to roll out more print, television and radio ads,
according to an ONDCP spokesperson, if Congress approves the agency's
current $150 million appropriations request this month.

At the press conference launching the mental illness campaign in May,
the Bush administration's drug czar, John Walters, emphasized, "New
research being conducted here and abroad illustrates that marijuana
use, particularly during the teen years, can lead to depression,
thoughts of suicide, and schizophrenia."

While the launch was attended by a former director of the National
Institute on Drug Abuse, the current occupant of the office, Dr. Nora
Volkow, did not attend or speak, nor did her deputies. This is
unusual: The National Institute on Drug Abuse is the federal agency
responsible for scientific research on the medical effects of drugs,
so a campaign about marijuana's health effects would ordinarily
feature at least one top representative discussing the science. The
agency's name does not appear on the list of organizations endorsing
the ad.

David Murray, special assistant in the drug czar's office, says that
the National Institute on Drug Abuse was "involved in every aspect" of
the planning of the campaign and "cleared and vetted" the statements
in the ad and on the Web site. He says the drug czar's office didn't
want to include more than one federal agency in the endorsements,
adding that Volkow was out of the country at the time of the launch.

"Our research provides most of the evidence undergirding the campaign
and we certainly support its goals," says Dr. Wilson Compton, director
of the Division of Epidemiology, Services and Prevention Research at
the National Institute on Drug Abuse. But Compton concedes that the
findings cited in the ad are "not completely established" and that
experts consider them "controversial" and worth further
investigation.

According to Murray, the latest available data shows that the
consumption of cannabis is a key risk factor for the development of
serious mental illness. With regard to schizophrenia, the campaign
cites one study ( http://www.ukcia.org/research/SelfReportedCannabisUseAsAFactorForSchizophrenia.pdf ) of nearly 50,000 Swedish soldiers between the ages of
18 and 20, published in the British Medical Journal in 2002, which
found that those who had smoked pot more than 50 times had a rate of
schizophrenia nearly seven times as high as those who did not use
marijuana at all.

The American Psychiatric Association is one of the major groups
backing the campaign; a spokesperson referred to part of the group's
policy statement as the reason for its endorsement: "The American
Psychiatric Association is concerned and opposed to the use of drugs
and alcohol in children."

Yet leading experts in psychiatric epidemiology (whom the APA
recommended contacting, but who do not officially speak for the
organization) are far from convinced about causal connections between
marijuana and serious mental illness. One key problem, they say, is
that it's very difficult to determine whether pot smoking predisposes
people to schizophrenia or whether early symptoms of schizophrenia
predispose people to smoking pot -- or whether some third factor
causes some people to be more vulnerable to both.

In the Swedish study, for example, when factors already known to
increase risk for schizophrenia were removed, such as a childhood
history of disturbed behavior, the connection between marijuana use
and risk for the disease was substantially reduced. Just one or two
additional unknown influences could potentially wipe out the apparent
marijuana-schizophrenia link, according to Dr. William Carpenter, a
professor of psychiatry and pharmacology at the University of
Maryland. Carpenter noted in a letter published in the British Journal
of Psychiatry in October 2004 that the same genes that predispose
someone to schizophrenia might also predispose them to substance
abuse, but that drug use might start earlier simply because many
people start using drugs in their teen years, while schizophrenia most
commonly begins in the early 20s.

Perhaps the strongest piece of evidence to cast doubt on a causal
connection between marijuana and schizophrenia is a long flat-line
trend in the disease. While marijuana use rose from virtually nil in
the 1940s and '50s to a peak period of use in 1979 -- when some 60
percent of high school seniors had tried it -- schizophrenia rates
remained virtually constant over those decades. The same remains true
today: One percent or fewer people have schizophrenia, a rate
consistent among populations around the world. This is in stark
contrast to studies linking tobacco smoking with lung cancer, where
rises in tobacco use were accompanied by rising rates of lung cancer.

"If anything, the studies seem to show a possible decline in
schizophrenia from the '40s and the '50s," says Dr. Alan Brown, a
professor of psychiatry and epidemiology at Columbia University. "If
marijuana does have a causal role in schizophrenia, and that's still
questionable, it may only play a role in a small percent of cases."

For the tiny proportion of people who are at high risk for
schizophrenia (those with a family history of the illness, for
example), experts are united in thinking that marijuana could pose
serious danger. For those susceptible, smoking marijuana could
determine when their first psychotic episode occurs, and how bad it
gets. A study published in 2004 in the American Journal of Psychiatry
of 122 patients admitted to a Dutch hospital for schizophrenia for the
first time found that, at least in men, marijuana users had their
first psychotic episode nearly seven years earlier than those who did
not use the drug. Because the neurotransmitters affected by marijuana
are in brain regions known to be important to schizophrenia, there is
a plausible biological mechanism by which marijuana could harm people
prone to the disorder. Both Brown and Carpenter say that people with
schizophrenia who smoke pot tend to have longer and more frequent
psychotic episodes, and find it very difficult to quit using the drug.

Of course, the U.S. government's current ad campaign targets a much
broader population than those highly vulnerable to schizophrenia,
fanning fears based on a statistically rare scenario.

The campaign also declares that today's pot is more potent than the
pot smoked by previous generations, implying heightened risk. Fine
sensimilla may seem more prevalent than ditchweed nowadays, but there
is debate over whether today's average smoker is puffing on stronger
stuff than the average stoner of the 1970s, as Daniel Forbes detailed
in Slate. And, as Forbes showed, the drug czar's office has grossly
exaggerated the numbers on this issue in the past.

Meanwhile, UCLA public policy expert Mark Kleiman has pointed out that
federally funded research by the University of Michigan shows that
since the 1970s the level of high reported by high school seniors who
smoked marijuana has remained "flat as a pancake." In other words,
even if today's kids are smoking more potent stuff, they don't get
higher than their folks did -- like drinking a few whiskey shots
rather than multiple mugs of beer, they use less of the good stuff to
achieve the same effect.

With regard to depression, evidence of a causal role for marijuana is
even murkier. In general, depression rates in the population did rise
sharply during the time period in which marijuana use also
skyrocketed. But there were so many other relevant sociological
factors that marked the last half of the 20th century -- rising
divorce rates, the changing roles of women, economic shifts, and
better diagnoses of psychiatric conditions, to name a few -- that
scientists have rarely focused on marijuana as a potential cause for
the increase in depression.

Murray maintains that scientists have simply overlooked marijuana in
their search for explanations. One study published in the Archives of
General Psychiatry in 2002, by New York University psychiatry
professor Judith Brook and several colleagues, found that early
marijuana use increased the risk of major depression by 19 percent.
But that's not a substantial amount, according to Brook. And though
the association remained after other factors were controlled for, such
as living in poverty, it weakened further. "I wouldn't say that it's
causal," Brook says. "It's an association. It appears to
contribute."

The campaign selectively uses another piece of data, citing an
Australian study published in the British Medical Journal in 2002 to
assert that for teens, weekly marijuana use doubles the risk of
depression. What that study found was that the risk doubled for teens
who smoke marijuana weekly or more frequently. And it found that
depression rates increased substantially in girls but not in boys. It
also noted that "questions remain about the level of association
between cannabis use and depression and anxiety and about the
mechanism underpinning the link."

Moreover, a June 2005 study by researchers at University of Southern
California, using the Center for Epidemiologic Studies' Depression
Scale, found that marijuana use was in fact associated with lower
levels of depression. Because the research was conducted using an
Internet survey, it's possible that the most severely depressed people
did not participate; nonetheless the study of more than 4,400 people
found that both heavy pot smokers and moderate users reported less
depression than did nonusers.

Dr. Myrna Weissman, a psychiatrist and leading epidemiologist of
depression at Columbia University, sums up the current research and
her view of marijuana's role in depression rates this way: "I can't
imagine that it's a major factor."

The distortion of science under the Bush administration is, of course,
nothing new.

"This is just more red-state culture-war politics," says UCLA's
Kleiman, of the latest anti-marijuana campaign. He notes that since
the government measures success in the war on drugs by a reduction in
the number of drug users -- rather than by declines in drug-related
harm or addiction -- marijuana is the obvious drug to go after.
According to the most recent National Survey on Drug Use and Health
from 2003, approximately 25 million Americans reported using marijuana
over the previous year; compared with approximately 6 million users of
cocaine and 1 million users of methamphetamine -- both far more
addictive substances -- marijuana is a big, soft target.

Yet, for a public desensitized to fear-mongering antidrug messages, a
campaign touting selected statistics from tenuous studies seems
especially tone deaf, if not irresponsible.

"If I tell my 15-year-old that he's going to have a psychotic episode
if he smokes pot, but he knows that his older brother already smokes
pot and is fine, is he going to believe me when I tell him that
methamphetamine damages the brain?" asks Mitch Earleywine, an
associate professor of psychology at the State University of New York
at Albany, who coauthored the USC study. Amphetamine psychosis is an
established effect of taking large doses of that class of drugs;
warnings about it appear on the labeling of prescription amphetamines.
"What's going to happen," says Earleywine, "is we're going to lose all
credibility with our teens."

The drug czar's office may soon face a full-blown credibility problem
of its own regarding its fight against marijuana. Drug warriors have
always had at least one powerful argument to fall back on when other
attacks against marijuana seem to go up in smoke -- but in the face of
a new study, that may no longer be the case.

Previous research has pointed to the notion that smoking marijuana
could cause cancer, the same way tobacco smoking has been
incontrovertibly linked with cancer and death. The Institute of
Medicine, charged by Congress with settling scientific debates, said
in its last major report on the subject in 1999 that the fact that
most users smoke marijuana is a primary reason to oppose its use as
medicine.

But that reasoning was called into question in late June, when Dr.
Donald Tashkin of the UCLA School of Medicine presented a large,
case-control study -- of the kind that have linked tobacco use with
increases in lung cancer -- at an annual scientific meeting of the
International Cannabinoid Research Society in Clearwater, Fla. Tashkin
is no hippie-dippy marijuana advocate: His earlier work has been cited
by the drug czar's office itself, because his research showed that
marijuana can cause lung damage. The new study, however, found no
connection between pot smoking -- even by heavy users -- and lung
cancer. In fact, among the more than 1,200 people studied, those who
had smoked marijuana, but not cigarettes, appeared to have a lower
risk for lung cancer than even those who had smoked neither.

The new research has not yet been peer reviewed, but it appears
congruent with earlier studies that found no link between marijuana
and increased cancer risk. If the data holds up to further scrutiny
and testing, one can only speculate what new ad campaign the drug
czar's office might cook up. Marijuana may not make most people crazy,
but this latest discovery could really drive the old drug warriors
bonkers.