According to a new report this week from a United Nations health commission, marijuana consumption has increased among Americans over the past four years, and more people are seeking treatment for marijuana-related health concerns. The number of people over the age of 11 who’ve used marijuana at least once in the last year rose from 10.3 percent to 12.1 percent in 2012, while there was a 59 percent increase in cannabis-related hospital visits from 2006 and 2010. At the same time, public perception of marijuana-related health risks has declined, whileTHC levels in marijuana have increased. While the measurements were taken before Colorado and Washington legalized recreational marijuana use, the report is sure to factor into the ongoing national debate on marijuana legalization.We thought now would be a good time to take a look at some common marijuana-related health claims and see how much water they actually hold. We'll give you both sides of the argument so you can decide for yourself.
Claim: Marijuana harms the lungs
Argument It Does: Marijuana requires smokers to take a longer and deeper inhalation than tobacco in order to feel its effects, and burns at a higher temperature than tobacco. As such, on a “per puff” basis, marijuana smoke is more harmful to the lungs than cigarettes: It contains about five times the concentration of carbon monoxide and three times as much tar. In addition, about one-third the tar is retained in the respiratory tract after smoking marijuana when compared with tobacco.Marijuana smoke also contains higher concentrations of certain carcinogens, notably benzopyrene and benzathracene, than cigarettes, and lung biopsies from marijuana-only smokers have shown tissue damage that’s recognized to be a precursor to cancer.Argument It Doesn't: Despite the carcinogens, tar content, and tissue damage that marijuana causes, no study has found that marijuana use actually leads to an increased risk of lung cancer.To take a recent example, a 2013 study from the University of California at Los Angeles concluded that “habitual use of marijuana alone does not appear to lead to significant abnormalities in lung function,” and furthermore, “findings from a limited number of well-designed epidemiological studies do not suggest an increased risk for the development of either lung or upper airway cancer from light or moderate use.” This confirmed the findings of a2004 study from Washington State and 2006 study published by the American Association for Cancer Research.
Of course, when baked and ingested orally, marijuana has no effect whatsoever on the lungs. LOL Claim: Marijuana has an adverse effect on brain development
Argument It Does: Numerous studies have concluded that early marijuana use, particularly during the teenage years, has measurable effects both on brain structure and cognitive performance. In a 2013 study published in Oxford University Press, researchers observed “cannabis-related shape differences” in numerous parts of the brain in marijuana smokers, and “subcortical neuroanatomical differences” between those who smoke and those who don’t. It also found that people who smoke marijuana have poorer working memory, a conclusion that’s been backed up by other studies.In addition, people who begin smoking marijuana during their late teens have been found to have shorter attention spans, poorer visual searchabilities, and worse abstract reasoning skills. One study also found that people who start smoking marijuana as teens have lower IQs as adults — and even when they stop smoking, their IQs don’t increase.Argument It Doesn't: It’s very difficult to determine whether the relationship between brain functioning and marijuana use is actually causal or merely correlative. The problem is confounding factors — especially socioeconomic status, which is correlated both with poorer cognitive functioning and early exposure to marijuana.Researchers in Norway concluded in 2013 that most, if not all, of the correlation between neuropsychological function and marijuana use can potentially be chalked up differences in socioeconomic status between smokers and non-smokers.Education is another confounding factor. Mandatory schooling gives people a boost in their IQ, but that boost slowly disappears as schooling ends. As a result, people who don’t go to college often show decreases in IQ during their 20s — and such people are also more likely to be marijuana smokers.
Claim: Marijuana is addictive
