Pubdate: Sun, 01 Nov 2015
Source: Arkansas Democrat-Gazette (Little Rock, AR)
Copyright: 2015 Arkansas Democrat-Gazette, Inc.
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Author: Sushrut Jangi, Boston Globe
Note: Dr. Sushrut Jangi is an internist and instructor in medicine at 
Beth Israel Deaconess Medical Center in Boston.

LET'S STOP PRETENDING MARIJUANA IS HARMLESS

These days, it's become fairly square to criticize marijuana and its 
rush toward legalization. Twenty-three states have condoned the drug 
in some form, with four permitting recreational use, and 
Massachusetts is set to vote on permitting it next year. The proposed 
federal CARERS Act of 2015 would let states legalize medical 
marijuana without federal interference and demote pot from a Schedule 
I drug-one with high abuse potential-to Schedule II. The path toward 
nationwide decriminalization is looking unobstructed.

But underscoring the incredible momentum to legalize marijuana is the 
misconception that the drug can't hurt anybody. It can, especially 
young people.

The myth that marijuana is not habit-forming is constantly challenged 
by physicians. "There's no question at all that marijuana is 
addictive," Dr. Sharon Levy tells me. She is the director of the 
Adolescent Substance Abuse Program at Boston Children's Hospital, one 
of a few programs designed to pre-emptively identify substance use 
problems in teens. At least 1 in 11 young adults who begin smoking 
will develop an addiction to marijuana, even more among those who use 
the more potent products that are entering the market.

Levy speaks of an 18-year-old patient who had started smoking 
marijuana several times a day in 10th grade, dropped out of high 
school, and been stealing money from her parents. "She and her family 
were at their wits' end trying to find appropriate treatment in a 
health care system that doesn't consider addiction to marijuana a 
serious problem," Levy says. "We are simply not prepared for the 
fallout of marijuana legalization."

Such perspectives have been obfuscated by those who might gain from 
legalization. "People strongly defend marijuana because they don't 
want legalization to be derailed," says Jodi Gilman, an assistant 
professor at Harvard Medical School with the Center for Addiction Medicine.

An insistence on the banality of the drug is especially dangerous 
among younger smokers, a population with an epidemic level of pot 
use. According to the most recent National Survey on Drug Use and 
Health, the use of tobacco and alcohol among 12- to17-year-olds has 
fallen in the past year, but habitual use of marijuana among those 12 
and up is increasing.

"If you go into a high school and ask the classroom, 'Are cigarettes 
harmful? Is alcohol harmful?' every kid raises their hands," Gilman 
says. "But if I ask, 'Is marijuana harmful?' not a hand goes up."

To bring balance to a narrative driven by pro-legalization campaigns, 
Gilman and others are interested in leveraging data to show pot's 
real effects. Last year Gilman published research on 
18-to-25-year-olds that showed differences in the brain's reward 
system between users and non-users. ("I got a lot of hate mail after 
that," Gilman says.) And data supporting the hazards keep 
accumulating. Recently Gilman found that in a group of college 
students, smokers had impaired working memory even when not acutely high.

Physician concern for marijuana's acceptance isn't because doctors 
are a stodgy bunch-their skepticism is rooted in science and in 
history. In the 1950s nearly half of Americans smoked tobacco, a 
level of adoption that rendered its health hazards invisible. 
Meanwhile, the corporate forces that drove cigarette smoking to its 
ascendancy actively subverted those that governed public health.

While marijuana has not been definitively shown to cause cancer or 
heart disease, its harmful cognitive and psychological effects will 
take time to capture in studies. The underlying biochemistry at work 
suggests deeply pathologic consequences. Tetrahydrocannabinol (THC) 
in marijuana attaches to receptors in the brain that subtly modulate 
systems ordinarily involved in healthy behaviors like eating, 
learning, and forming relationships. But THC-which has been 
increasing in potency in legal products being sold in places like 
Colorado-throws the finely tuned system off balance.

"Smoking pot turns the volume on this system way, way up," says 
Jonathan Long, a research fellow at the Dana-Farber Cancer Institute.

Each hit of THC rewires the function of this critical cognitive 
system: Early evidence in mice has shown that repeated exposure to 
THC causes these receptors to disappear altogether, blunting the 
natural response to positive behaviors and requiring higher doses to 
achieve the same effect. Marijuana exploits essential pathways we've 
evolved to retrieve a memory, to delicately regulate our metabolism, 
and to derive happiness from everyday life.

Medical science at its best operates independently of forces that 
drive the market and its associated politics. It was science that 
eventually curtailed the power of Big Tobacco and prevented nearly 
800,000 cancer deaths in the United States between 1975 and 2000. As 
marijuana marches toward the same legal status as cigarettes, its 
potential hazards will require equal attention by science.

The argument here isn't whether marijuana should be legal. There are 
champions on either side of that debate. Instead, should the drug 
become widely available, it's to our detriment to blindly consider 
marijuana's legalization a victory worthy of celebration. We must be 
cautious when societal shifts can affect health, especially among our 
most vulnerable populations.
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MAP posted-by: Jay Bergstrom