Many people today, especially younger ones, regard cannabis as a totally benign substance, not really a “drug” at all. (Of course, many people make the same mistake about alcohol.)  In fact, cannabis is a drug -- and one which, like any psychoactive substance, carries with it a unique set of risks. In addition to the legal risks, where cannabis is still forbidden, there are a number of health risks (both short and long term) that one should consider before "lighting up."  


Health Risks from Smoking Marijuana 

Many studies have looked at whether marijuana smokers run risks of lung and oral cancer, as tobacco smokers do. Cannabis smoke does contain some known carcinogens, but probably not enough to present a serious risk of cancer. Although one New Zealand study found that smoking a joint a day increased the risk of lung cancer by about eight percent per year, most research is either inconclusive or shows no increased risk.  For cannabis smokers who also smoke tobacco, it's unclear if and by how much adding cannabis to the mix might increase their risk.

Although the cancer risk appears minimal, smoking marijuana can cause lung irritations, phlegm and coughing, just as tobacco smoking does. Inhaling any kind of smoke is just not good for you and because marijuana is inhaled more deeply than tobacco, the amount of tars is roughly three times that of regular cigarettes. Some marijuana smokers respond to these concerns by using vaporizers or switching to edibles.

 Although less portable, higher quality vaporizers like the Volcano appear to be a good fix; lower quality vape pens as well as ingredients added to concentrates to make them burn better (e.g. propylene glycol) may create toxic by-products. 

Switching to edibles solves the lung related issues from primary and secondary smoke, but can create a new set of problems: The effects of edible marijuana are longer lasting, more intense, and harder to titrate than smoking. Even veteran marijuana smokers sometimes find edibles hard to handle, so novice users should proceed with caution.  

Psychological Risks

While marijuana isn’t directly fatal (it’s virtually impossible to die of an overdose of marijuana alone), tens of thousands of people end up seeking emergency care each year for reasons related to marijuana use. 

Marijuana can pose acute psychological risks, especially when it is used in high doses. It is still more dangerous when combined with alcohol or other drugs. Even low doses of marijuana and alcohol consumed together can greatly increase driving risk, and marijuana’s anti-emetic effect, which makes it valuable to chemotherapy patients, can pose a serious hazard to binge drinkers: vomiting is one way the body protects itself from alcohol poisoning.

Although marijuana won’t kill you, extremely high doses might make you wish you were dead (or even convince you that you’re dying). "Getting too high” sounds like “having too much fun” until it happens to you, as Lil Dicky and Maureen Dowd can testify.  Cannabis overdose can lead to panic attacks, paranoia, and, rarely, hallucinations and psychotic episodes. Those seasoned in the ways of marijuana are less likely to have severe adverse reactions, but dabbing and taking edibles are notoriously tricky methods of marijuana ingestion and have felled many a stoner. That’s because the methods involved in dabbing and in consuming edibles make it hard to control how much of the drug is in your system. Dabbing delivers a huge dose quickly, sometimes with frightening results; a single hit can be an overdose. Taking cannabis in the form of food or drink means that the drug effects come on more slowly but also last longer. The variability in potency and lengthy duration of effects suggests that edibles are a bad idea for the casual user. While those who smoke or vaporize cannabis can, with reasonable safety, take another puff if they find they’re not as high as they want to be, that strategy doesn’t work with edibles; the risk of an overdose is too great.

Risks of Dependency

The idea that cannabis is “non-addictive” has become widespread, but the facts are otherwise: of those who report using in the past month, about 20% – by their own self-reports – meet the diagnostic criteria for Substance Use Disorder. Although the degree of dependence is considered weak by most experts, as compared with alcohol, heroin or tobacco, the number of people seeking treatment for cannabis is troubling.

The risk that a marijuana user will become dependent on the drug varies according to many social and personal factors.  Statistically, one of the largest factors appears to be the age of onset - of first use. The younger a person is when introduced to cannabis, the more likely that person is to become dependent at some point. One 1990-1992 study in the U.S. found that that for those who first used marijuana after they were 25 years old, the probability that they would become dependent at some point in their lives was 9 percent, compared to 15 percent for alcohol and 16 percent for cocaine. The same study found that the “capture rate” for those who first used marijuana before age 24 was about 15 percent.The age of first marijuana use has been drifting downward (currently about age 16) while the potency of marijuana continues to rise. This poses a serious concern about the capture rate for present and future generations as well as questions about marijuana's effects on developing brains.

Quantifying the risks associated with marijuana and making a science based personal decision is difficult for several reasons. Cannabis is not a standardized good; the potency and the chemical composition of cannabis varies greatly across studies as does the definition of regular, heavy and occasional use. For ethical reasons, scientists cannot do controlled studies to answer some of the key questions: no one is going to randomly assign half of a group of 15-year-olds to the cannabis use group. Instead, we must rely upon converging lines of evidence from many observational studies, which are harder to interpret because the observed differences between users and non-users may reflect who chooses to use cannabis rather than actual drug effects. The lack of standard definitions, doses, and products makes it challenging for scientists and policy makers to tease out the intricate web of cause and effect and harder still for the consumer.