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By: David Warmflash

Recent david-warmflashyears have seen changes in the legal status of cannabis (tetrahydrocannabinol, THC) in several U.S. states. Currently, 25 states permit marijuana for medical use. Four of those states—Alaska, Colorado, Oregon, and Washington—also permit recreational marijuana, and use will be expanding, due to passage of ballot measures in the recent election. On November 8, California, Massachusetts, Maine,, and Nevada voted to legalize recreational cannabis, while Arkansas, Florida, North Dakota, and Montana all voted up measures favoring medical use.

Prior to the election, California’s Lieutenant Governor Gavin Newsom remarked, “If we’re successful, it’s the beginning of the end of the war on marijuana.” He meant at the federal level, where the Drug Enforcement Administration classifies marijuana as a Schedule 1 drug—meaning no prescriptions can be written, because it is considered dangerous with no medical use.

Newsom’s prediction could turn out to be right, as the sheer size of the Golden State makes it a possible tipping point for the country. Also, politicians run the risk of being labeled anti-progressive if they oppose legalization of recreational cannabis. Favoring legalization for recreational use implies support for de-scheduling, which is to say making cannabis like tobacco and alcohol; adults could purchase it, no prescription required.

Changing Perspective in Society

Medical cannabis is gaining acceptance based on real or perceived benefits in patients undergoing cancer chemotherapy and those with neurodegenerative conditions, such as Parkinson disease. Furthermore, a political movement for decriminalization is based on sober assessments of drawbacks versus benefits of imprisoning people for marijuana offenses. Many in the prison system are there merely for possession and there’s racial inequality to boot.

A policy position intermediate between the status quo and de-scheduling is rescheduling cannabis down to a lower level. Schedule 3 might be logical, because it implies some level of abuse potential and dependence (physical or psychological) and some accepted medical use, but chances are that it would first go to Schedule 4, the same level that includes cocaine.

Negative Health Effects

Evidence that marijuana has detrimental effects on multiple organ systems exists, but strength and consistency of evidence varies depending on the effect and organ system. In terms of behavioral symptoms, a fair amount of evidence implicates cannabis as a cause of anxiety, panic disorder in particular. The case is somewhat weaker, but still plausible, when it comes to psychotic symptoms and other psychiatric sequelae. THC at blood levels 2‒5 ng/mL are linked to significant substantial impairment of driving skills. The impairment lasts up to 24 hours after cannabis use, because the drug is metabolized more slowly than other drugs affecting motor skills, such as alcohol.

The possibility of marijuana causing pulmonary disease, including lung cancer, has been a concern for many decades for a couple of reasons. Firstly, smoking is the most common way to take marijuana, which contains most of the same carcinogens that tobacco contains. These include several polyaromatic hydrocarbons found in tars, and marijuana contains more tars per cigarette compared with tobacco. Second, since marijuana is inhaled more deeply and held within the lungs longer compared with tobacco smoking, the carcinogens are thought to penetrate better. Various epidemiological studies have associated heavy use of cannabis (generally defined as more than one cigarette [joint] per day for several years) with chronic bronchitis as well as destruction of alveolar macrophages, leading to pneumonia. When it comes to lung cancer, epidemiologic data are somewhat conflicting; a few studies reveal a connection while others do not. This is consistent with the hypothesis that cannabis smoke may be carcinogenic in certain people but not others, due to genetic differences affecting susceptibility. Cannabis also has been implicated in malignancies outside of the respiratory system. Additionally, a recent study has implicated heavy marijuana use as causative of osteoporosis.shutterstock_297172937

Coming to an Agreement

Advocates of marijuana legalization have effectively emphasized the prison paradigm. Large segments of the nation’s incarcerated people are in for merely for possession. Most of us do not find this situation palatable. But let’s remember the health paradigm as well. Those unsatisfied with rescheduling will continue to push for de-scheduling. Realizing the growing national consensus that jailing people for possession is not practical, perhaps policymakers should hash out the details on what form legalization should take. In doing so, they might also consider growing evidence for marijuana’s negative health effects, at least when it is smoked. What is the best solution for the country? Or, could it be that marijuana policy should be handled very differently state by state?

David Warmflash, M.D., is an astrobiologist, science writer, and physician. He is principal investigator on a Planetary Society-sponsored investigation of the effects of the space environment on organisms.