Is Pot as Benign as we Thinks?

We used to fear Mary Jane, then we laughed about her, and now many of us think she’s downright wholesome. Marijuana’s public image has undergone a stunning transformation since the scare-mongering of Reefer Madness and the dope comedies of Cheech and Chong, but many doctors believe that weed’s rehabilitation as a virtual wonder drug may be distracting us from its real health dangers.

It seems that plenty of people have bought the idea that marijuana is a harmless herb, or better. Stories proclaiming the benefits of “medical marijuana” – for ailments as varied as arthritis, MS, glaucoma and Alzheimer’s – abound in mainstream media like International Business Times, and at patient support sites such as Livestrong.org. Voters in Washington and Colorado recently approved measures to begin legalizing pot, and a reinvigorated movement in B.C. is pushing for similar changes. A poll in the summer showed that two-thirds of Canadians are okay with decriminalizing weed for personal use.

Pot supporters promote its supposed benefits at big trade shows like the Treating Yourself Expo, which celebrated its third annual edition in May in Toronto. Doctors aren’t nearly so well mobilized on the issue, but many say the health risks of smoking marijuana are more extensive and better understood than ever before.

“There’s a pretty potent lobby that makes claims about the medical benefits of cannabis, and anybody who disputes them is labelled part of the war on drugs,” says Dr. Meldon Kahan, medical director of the Substance Use Service at Women’s College Hospital in Toronto. “But there’s no role, or hardly any role, for smoked cannabis in the treatment of chronic pain. There are safer alternatives, such as cannabis in pill form or inhalers. There are toxins in cannabis smoke that are carcinogens, and that accelerate heart disease. Smoked cannabis is addicting, unsafe during pregnancy and especially dangerous for young people, in terms of triggering psychosis, depression and mood disorders.”

According to Health Canada, addiction is a complex phenomenon that includes psychological cravings, difficulties in controlling use, symptoms of withdrawal, and persistence in the addictive activity even when it is obviously damaging one’s health, relationships and day-to-day functioning. All can apply to heavy cannabis smokers, says Kahan.

Teens are still developing neurologically, he says, which makes them more vulnerable than adults to the adverse effects of marijuana, especially of the powerful strains for which B.C. is famous. A recent report in the Proceedings of the National Academy of Sciences about a long-term study of more than 1,000 pot-using teens in New Zealand said that those who continued smoking into their 30s suffered significant cognitive deficits related to memory, reasoning and ability to process information.

According to a 2007 report by Health Canada, 8.2 per cent of young people use cannabis on a daily basis. Many teens smoke weed to cope with the anxieties of adolescence, and find it very tough to quit.

“People who take cannabis regularly get a mood-leveling effect,” Kahan says. “When they stop suddenly, there’s a tremendous rebound anxiety that can go on for days or weeks, and that makes them want to take it again.”

Many young users smoke it with tobacco, a combo that researchers are finding to be much more addicting than marijuana alone. Dr. Bernard Le Foll, a leading researcher at Toronto’s Centre for Addiction and Mental Health, says his research shows that when nicotine and tetrahydrocannabinol (or THC, the element in pot that delivers the “high”) are received together, they magnify each other’s effects on brain chemistry.

A 2009 study at the University of B.C. led by Dr. Wan Tan found “a significant synergistic effect between marijuana smoking and tobacco smoking” that increases risk for chronic obstructive pulmonary disease. COPD (which includes emphysema and chronic bronchitis) can aggravate the risk of pneumonia, heart problems, glaucoma and lung cancer.

John Westland, a social worker at the Hospital for Sick Children’s Adolescent Substance Abuse Outreach Program, says many of his teenaged patients combine weed and tobacco in the quick-hit form known as “poppers” (not to be confused with the amyl nitrites inhaled at clubs and raves). They use a modified water pipe that delivers a head rush they don’t get from smoking straight marijuana.

“From my experience with my patients, I would say the addiction potential is higher for sure,” Westland says. The relative cheapness of poppers is also a draw, as is the societal notion that pot is pretty much okay, and that a few cigarettes won’t hurt you. “As their perception of risk goes down, use goes up,” Westland says. Withdrawal is an ugly process that deprives jittery patients of sleep and appetite, he says, and can drag on through cycles of relapse and repeated efforts.

So why is weed regarded as relatively benign? How can any kind of smoking seem okay in 2012?

Pot’s current reputation has certainly benefited from growing skepticism about established medicine. Marijuana is seen as whole and natural, not a refined pharmaceutical produced by a big corporation. Weed as a painkiller or treatment for nausea may appeal to the same people who seek out herbal equivalents of pharmaceuticals such as Valium, whose effects can be mimicked by valerian root.

Pot also benefits from current demographics. In contrast to seniors of, say 20 years ago, aging boomers today have fond memories of sharing a joint in their college dorm, and may not be aware that today’s marijuana is probably much more potent than what they smoked in ’68.

The widespread feeling that prohibition has failed both users and society as a whole has also helped. Surely a little pot smoking can’t be more harmful, say weed activists, than a harsh legal regime that has cost us so much in money and damaged lives.

“Whatever people think the harms of cannabis are, those are best reduced by a legally regulated system,” says Dana Larsen, leader of a Sensible B.C. initiative to decriminalize weed in B.C. In any case, he says, “The use of cannabis since the 1960s has pretty much steadily risen in Canada, as has the severity of the laws, so the idea that prohibition is doing anything to keep cannabis out of the hands of youth is totally wrong.”

Chronic use of the chronic before age of 18 can cause “lasting harm to a person’s intelligence, attention and memory” – and quitting pot later in life doesn’t reverse the damage, says daunting new research out of New Zealand.

The study, which followed 1,037 Kiwis for nearly 40 years, found that adolescents who smoked marijuana persistently for years showed declines of eight IQ points when their scores were tabulated at age 13 and then at 38. Teens who got stoned regularly all scored significantly worse than their sober counterparts on tests measuring memory, reasoning and processing speed, with family and friends of users corroborating the findings anecdotally.

“Marijuana is not harmless, particularly for adolescents,” lead researcher Madeline Meier, a post-doctoral researcher at Duke University, said in a release. “Somebody who loses eight IQ points as an adolescent may be disadvantaged compared to their same-age peers for years to come.”

Adolescent tokers are particularly vulnerable to lasting mental deficits because their brains are still developing, the researchers explained. Subjects who didn’t hit the bong until they were adults “with fully-formed brains” did not exhibit these drastic mental declines.

(Approximately five per cent of the respondents were deemed “marijuana-dependent,” that is, lighting up more than once a week before turning 18. The researchers controlled for other drug and alcohol use and disparities in education.)

What isn’t clear from this study is what quantity of weed causes damage, and what age (if any) might be safe for regular use.

Marijuana use is up among American teens, who are now more likely to smoke pot than tobacco, according to a 2011 University of Michigan study.

That study found one in every 15 high-school seniors getting high on a daily or near daily basis, the most substantive rates seen since 1981. One hypothesis for the resurgence is that teens perceive few risks associated with the drug, with many refusing to even call it a drug.

In Canada, the prevalence of pot use among Canadians aged 15 and over decreased to 9.1 per cent in 2011 from 10.7 per cent in 2010.

Still, the rates for youth aged 15 to 24 were three times higher than for their over-25 counterparts: 21.6 per cent versus 6.7 per cent.

According to Health Canada (2011 Stats):

• Among Canadians 15 years and older, the prevalence of past-year cannabis use decreased from 10.7% in 2010 to 9.1%.
• The prevalence of past-year cannabis use decreased since 2004 for males (18.2% vs. 12.2%), females (10.2% vs. 6.2%) and youth aged 15-24 years (37.0% vs. 21.6%).
• Among youth, aged 15-24 years, past-year use of at least one of 5 illicit drugs (cocaine or crack, speed, hallucinogens (excluding salvia), ecstasy, and heroin) decreased from 11.3% in 2004 to 4.8%.
• The rate of drug use by youth 15-24 years of age remains much higher than that reported by adults 25 years and older: three times higher for cannabis use (21.6% versus 6.7%), and five times higher for past-year use of any one of five drugs excluding cannabis (4.8% versus 1.1%).
• The rate of past-year psychoactive pharmaceutical use decreased among Canadians aged 15 years and older from 26.0% in 2010 to 22.9%. Of those who indicated they had used an opioid pain reliever, a stimulant or a sedative or tranquilizer in the past year, 3.2% reported they abused such a drug. Abuse is use for the experience, the feeling caused, to get high or for other non-prescribed reasons.
• Among Canadians 15 years and older, the prevalence of past-year alcohol use was 78.0%, not statistically different from previous years.
• Less than three quarters of youth (70.8%) reported consuming alcohol in the past year. This is a decrease from 2004 when 82.9% of youth reported past-year use of alcohol.
• Canada’s Low-Risk Alcohol Drinking Guidelines were received in November 2011 by the Canadian federal, provincial and territorial health ministers. Of the five guidelines, the first two apply to all Canadians and address long-term (chronic) effects like liver disease and certain cancers, and short-term (acute) effects such as injuries and overdoses, respectively. In 2011, 14.4% of Canadians aged 15 years and older exceeded the recommended quantity of alcohol outlined in guideline 1 for chronic risk and 10.1% exceeded the recommended quantity of alcohol outlined in guideline 2 for acute risk.

Source: CAMH