CANNABIS (MARIJUANA) MYTHS: WHAT SCIENCE SAYS

We all know the stereotypes: Marijuana users are lazy couch potatoes or free-wheeling hippies who are unmotivated to work, exercise, or otherwise engage in a healthy lifestyle. But does the research bear out those assumptions? Or, are they myths?

Marijuana usage comes with a host of misconceptions, but the myths don’t stand up to the latest research.

Marijuana laws—and attitudes—are changing at a swift pace across the United States. The drug, also commonly referred to as cannabis, has been legalized for recreational and medicinal use in numerous states, with legalization in more states on the way. Consider these facts:

• According to data from Statista, the estimated number of cannabis consumers in the United States was 40.3 million people in 2019; that number is expected to rise to 46.6 million by 2025.
• A recent Gallup poll shows that 68% of American adults now support legalization of recreational marijuana.
• Legal sales of marijuana at cannabis dispensaries skyrocketed during the early months of the coronavirus outbreak in 2020, with reports of average store revenue increasing by 52% to 130% across the nation at that time.

Given marijuana’s increasing popularity and acceptance, perhaps it’s time to take a look at some of the preconceptions about the drug. Here are three myths about cannabis use and what the latest research says about their veracity.

Myth No. 1: Smoking cannabis leaves you unmotivated

Does using marijuana make you a slouch? This reputation has been perpetuated by stonier characters in popular movies and culture, but the perception goes beyond that. As noted in a review published in Psychology of Addictive Behaviors, “amotivational syndrome” has been associated with heavy cannabis use for over 50 years, and this is largely due to the drug’s interactions with dopamine motivational circuitry in the brain. The authors note that the dopamine neurotransmitter reward system is activated by cannabis use, and several theories suggest that this may lead users to become uninterested in activities–other than consuming cannabis. However, the review’s authors found that there isn’t a lot of evidence to support this. They analyzed the findings of 22 studies, focusing on questions about whether cannabis users are less motivated than others and whether there is a causal relationship between cannabis use and motivation. Of the 22 studies, nine found that heavy cannabis use was associated with decreased motivation. However, only six of these studies controlled for the influence of confounding variables, which were not consistent across the studies. For example, depression was not measured, despite its scientifically supported effect on motivation. In fact, one of the studies found that, after controlling for depression, the apparent relationship between cannabis use and “reward learning” did not persist. “Importantly, studies have varied in the extent to which they controlled for confounding variables, as well as in their definition of motivation, their assessment tools, and the levels of cannabis use in their sample,” the authors wrote. The authors ultimately concluded that study findings are mixed on whether reduced motivation is a common condition for cannabis users. While there is some evidence of a causal relationship between cannabis use and reduced motivation, there are still too many research gaps—including questions over whether reduced motivation is related more to addiction, rather than cannabis specifically.

Myth No. 2: Cannabis users don’t exercise

On a similar note, the idea that cannabis users spend all their time on the couch and avoid any kind of physical activity has persisted for years. However, a new study published in Preventative Medicine may put an end to this apparent misconception. The research involved pulling information from the National Longitudinal Study of Adolescent to Adult Health, a study which began in 1994 and includes data on 20,745 students in middle school or high school. The study involved five sets of surveys conducted throughout the participants’ lives, with the fifth completed in 2018 when the participants were between 34-42 years old. Surprisingly, researchers found no significant negative associations between light, moderate, or heavy cannabis use and levels of exercise within the past 30 days. “In fact, in instances of significant correlation, the relationship points to increased exercise activity for cannabis users, though this finding does not necessarily indicate a causal effect,” the authors wrote.

These findings are at odds with much of the existing literature, they noted, which generally shows a negative relationship between marijuana use and exercise. “As additional states legalize the medicinal and recreational use of marijuana, perhaps its impact on exercise, one of the leading social determinants of health, is not necessarily a primary concern.”

The study findings line up with those of previous research conducted by the same research team, which found no relationship between cannabis use and weight status—in fact, daily cannabis users in that study were found to have about 2.7% lower weight than non-users.

But if stoners are more active physically than perhaps we imagined, what about the effects of cannabis on their sex lives? According to some research, male and female marijuana users had more monthly and daily sex compared with those who never used it.

Myth No. 3: Stoners are always happy and carefree

We may have an image in our head of a smiling user, but according to a study published in the Proceedings of the National Academy of the Sciences, that perception is not entirely correct.

The study set out to investigate the impacts of chronic marijuana use on the participants’ emotions. Researchers looked at a cohort of 48 individuals, half of whom were heavy cannabis users and half of whom were a control group. They gave all the participants methylphenidate (commonly known as Ritalin), a drug that stimulates extracellular dopamine, in order to test participants’ dopamine reactivity.

Researchers found that, while dopamine receptor availability between the two groups didn’t differ at the beginning of the study, the cannabis users exhibited “markedly blunted responses” when challenged with the methylphenidate. Specifically, they found that the chronic marijuana smokers reported lower “positive” and higher “negative” scores of emotionality, along with increased stress and irritability. Researchers noted that these reactions are consistent with decreased dopamine reactivity. So, maybe marijuana users are not as happy-go-lucky as we thought.

Myth Number 4: Cannibus is a “gateway” drug that leads to a high rate of addiction to “hard” drugs such as opiates.

The conventional attitude expressing the relationship between marijuana and opiate use holds that use of marijuana commonly, if not inevitably, leads to the use of opiates, such as morphine and heroin. Many proponents suggest there is a “domino” effect as individuals begin their addiction with cigarettes, which leads successively to marijuana and opiates. But is there evidence for such an association?

Among confirmed opiate addicts, there is a high rate of use of marijuana, which often begins prior to narcotic use. But these data are derived retrospectively from a select group likely to have underlying personality traits that cause them to seek more than one drug or experience. Also undermining the likelihood of a direct association between marijuana and opiates is the fact that their relative use is influenced by a person’s environment. For instance, in metropolitan areas where drug dealers are numerous, there appears to be greater acceptance of narcotics among those who have at least experimented with marijuana. On the other hand, in many Southern states, opiate addiction is often unassociated with marijuana. And according to a recent study of people who have used marijuana at least once, they have only a 1 in 26 chance of using opiates at any time in their life. The author concluded that marijuana experimenters rarely turn to hard drugs, which is further substantiated by the fact that, in general, there are far more marijuana nationwide than narcotic users. Finally, there is no evidence that marijuana is more of a gateway drug than is alcohol, a substance that possesses a greater potential threat of subsequent addiction than does marijuana.

Lung pollution: A potential, non-mythical, threat

Much like tobacco smoke, marijuana is an irritant to the throat and lungs, and causes cough. It contains tar and volatile chemicals that could raise the risk of cancer and lung disease.

According to the NIH, inhaled marijuana smoke is linked to large airway inflammation, higher airway resistance, and lung hyperinflation. People who regularly toke experience chronic bronchitis, and are more likely to seek outpatient treatment. Other concerns presented by the NIH include immunosuppressive effects on the respiratory system, as well as the increased risk of lung infections such as pneumonia. We know that inflammation, infection, and immunosuppression are closely tied to cancer, but more research will be needed to establish such a link. In the meantime, however, if one desires marijuana, it might be more safely consumed through ingestion rather than inhalation.

Marijuana is not associated with serious health problems for most young, healthy users, although occasional myocardial infarction (heart attacks), stroke, and other adverse cardiovascular events have been reported.. However, marijuana smoking by people with cardiovascular disease is potentially risky because of its ability to raise cardiac work, to induce carbon monoxide into the blood, and to produce certain unfavorable blood pressure effects.

BOTTOM LINE

While these studies mostly highlight the need for further research on cannabis—particularly in light of its increasing popularity and availability—perhaps the findings will at least make us think twice before buying into stereotypes about cannabis and its users.