To Puff or Not to Puff: Science’s Two Cents in the Marijuana Debate

Photo credit to Wikimedia Commons
Photo credit to Wikimedia Commons

By Shannon Kelleher
BU News Service

With marijuana now legalized for medical use in twenty-three states and for recreational use in two (Colorado and Washington), American interest in the leafy green drug is on the rise. In fact, according to the Pew Research Center, 48% of American adults report that they have tried marijuana, up from 40% only two years ago. However, despite its increasing popularity there appears to be a lack of both scientific knowledge and public awareness about the risks and possible benefits of marijuana.

Despite pre-clinical research explaining the drug’s mechanism and many case-control studies of people with a history of use, scientists have conducted few clinical marijuana studies. This is largely because it is considered a schedule 1 controlled substance, the most dangerous government drug listing. Heroin is also schedule 1, while cocaine and methamphetamines are schedule 2. Alcohol and tobacco are not listed. Marijuana is further restricted in that researchers must receive permission from a host of federal agencies in order to study it in clinical trials. Even then, they can only obtain it from the National Institute on Drug Abuse (NIDA).

There has scarcely been a point in American history when the government did not restrict marijuana research. According to Associate Professor of History Dr. David Herzberg at the University of Buffalo, as far back as the 19th century most states recognized marijuana as a poison and limited its sale. Restrictions have only tightened over the years, with the Marijuana Tax Act of 1937 requiring physicians to receive federal permission before prescribing the drug (although by that point most states had prohibited it). In 1970, marijuana was officially listed as a schedule 1 drug under federal law, resulting in the current series of hurdles that researchers must clear in order to obtain it. At the Center for Medicinal Cannabis Research, the largest facility of its kind in the United States, Dr. Atkinson acknowledges that it initially took his research team two and a half years to receive the marijuana they needed for clinical trials; the process has now been streamlined to about a year and a half.

While existing studies suggest that marijuana poses less severe health threats than legalized drugs like tobacco and alcohol, researchers nonetheless worry about two of its effects on frequent users: addiction and lowered IQ. NIDA states on its website that about 9% of users become addicted, although the number rises to 17% for those who start in adolescence. According to a 2014 study of marijuana use by college students published in the journal Addictive Behaviors, cannabis smokers performed worse on memory and cognition tests than non-smokers. McLean Hospital clinical researcher Dr. Kevin Hill, who treats marijuana addicts with gradually smaller doses of FDA-approved marijuana to combat withdrawal symptoms, says that “research is quite clear that regular use is going to catch up with you.” While it may be less addictive than some other drugs, marijuana poses a risk of dependency that can detract from a user’s quality of life.

Frequent marijuana use may also impair attention, executive function, and memory in adults—and it may weaken cognitive development in adolescents. A 2007 study published in the Journal of the International Neuropsychological Society found that 16-18 year-old marijuana users who quit for a month scored significantly lower on tests measuring their ability to sequence information than their peers who never used it. This suggests they might have a harder time learning, which could explain their lower GPAs; the users averaged a 3.0 whereas the controls averaged a 3.4.While it is difficult to definitively assess the effect of heavy marijuana use on IQ, Hill says that brain imaging studies at McClean show that users require more mental energy to carry out the same tasks as non-users. According to Dartmouth Professor of Psychiatry Dr. Alan Budney, even weeks after quitting long-term use, subsequent improvements in cognitive functioning cannot account for the level of mental aptitude a user would have had if he or she never started using.

Additionally, marijuana smoke has been shown to cause irritation in the lungs and excessive phlegm just like with tobacco smoke, although, as Budney notes, it has not been linked to cancer. The drug has not been directly correlated with psychosis, although researchers believe that it may cause psychosis to be expressed in those with a genetic predisposition.

On the other hand, the drug seems to have benefits. From the handful of clinical trials they have conducted and through observational and case study data, researchers have determined that marijuana can be effective in treating certain health conditions. Well-substantiated data suggests that it is an effective treatment for three ailments: chronic pain, neuropathy, and nausea. Dr. Atkinson’s research shows that marijuana works well with other pain treatments which are not sufficient by themselves. When doctors paired marijuana with these treatments, 30% of patients noticed decreased pain compared with a placebo sample. However, as Hill says, “Outside of [chronic pain, neuropathy, and nausea], the data’s not good. It’s not a yes/no, black/white thing.”

While marijuana may indeed have legitimate therapeutic benefits, it is extraordinarily difficult to standardize the dosage of smoked substances—and that’s where researchers have a problem with medical marijuana dispensaries. “With marijuana, what would you tell anybody?” Budney says. “You should take a 6% THC cigarette and you should puff on it 3 times a day for 6 weeks? We haven’t worked any of that out. That’s why we don’t have any smoked medicines right now.” For this reason, doctors don’t actually write prescriptions to dispensaries. These function more like herb stores: unregulated, offering varying concentrations and making sometimes unsubstantiated claims about cures.

It may be challenging at best to determine marijuana’s medicinal value, but scientists have found another way to tap into the drug’s silver lining. By designing compounds that mimic THC—the chemical kick behind marijuana’s intoxicating effect—rather than relying on the cannabis plant, researchers avoid a mess of clinical complexities and political inefficiencies. The National Institute of Health has funded research for these synthetic siblings of marijuana, like Dronabinol and Nabilone, to treat pain and nausea in chemotherapy and AIDS patients. But despite the government’s burgeoning interest in synthetic cannabinoids, there is no sign that federal roadblocks to researching the plant itself will be lifted anytime soon. And so the debate rages on.

“There’s only two types of people in the marijuana debate,” says Atkinson. “Those that are for it think it’s wonderful and there are no ills, and those that are against it think it’s the device of the devil and has no benefit.”

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