Cannabis Triples Your Risk of Death from High Blood Pressure, says US NHANES Study

by Leigh on June 19, 2018

cannabis risks green lightAccording to an analysis carried out by the U.S. National Health and Nutrition Examination Survey (NHANES), if you use marijuana you triple your risk of dying from hypertension (high blood pressure). The new study found that compared with non-users, marijuana users had 3.42 times the risk of death from hypertension. This is higher than the risk from cigarette smoking alone (hazard ratio of 1.06). Cannabis risks also appear to include symptoms of psychosis in teens, according to other research. And an unusual syndrome called cannabinoid hyperemesis is confounding many emergency physicians as marijuana use increases.

Cannabis Risks Include Death from Hypertension

This latest study, published in the European Journal of Preventive Cardiology, looked at survey answers from over 1200 individuals (average age was 37.7). The participants reported on their health, smoking habits, and marijuana use. Just over a third didn’t smoke or use marijuana (34%), 21% used marijuana only, 21% smoked and used marijuana, and 4% smoked cigarettes only. Some 16% used marijuana and had smoked in the past, and 5% were former smokers.

The study was limited by the small sample size and the use of self-reporting. However, the results certainly suggest that there are higher cardiovascular risks from cannabis use than there are with cigarette smoking. This isn’t all that surprising given the bevy of reports showing serious heart attacks and strokes occurring in marijuana users with no previous history of high blood pressure.

Indeed, many emergency department physicians are now encountering previously rare adverse effects of cannabis use at an increasing rate as legalization continues to spread across the U.S. Cannabinoid hyperemesis, for instance, is bringing more marijuana users to the ED and confounding many doctors who have never seen this particular presentation before. While beta blockers may help in the short term, the only known ‘cure’ for this condition is to stop using marijuana. This issue was discussed recently on episode 3 of the podcast DDx.

Legalizing Cannabis

In the U.S. there are currently 29 states and DC that allow cannabis use for medical reasons. Eight states and DC have fully legalized cannabis. As more states consider legalizing marijuana, activists tend to focus on the purported and proven benefits of the drug. This has the unfortunate effect of creating a dangerously unbalanced conversation that can put physical and mental health at risk. While legalization will make it easier to research the effects of marijuana in a more robust and comprehensive way, legalization itself could send a message that cannabis poses no risks. To give us a clearer picture of how cannabis affects all individuals, regardless of race, age, and sex, we need more research, and quickly.

Cannabis Increases Risk of Psychosis in Teens

Recent research has found, for instance, that cannabis use increases the risk of psychosis for all teens. This study was published in JAMA Psychiatry and debunked the commonly held view that cannabis only increases psychosis risk in vulnerable teens. The latest data strongly suggests that all teens are at risk, not just those with a family history of schizophrenia or specific biological risk factors.

This study used an interesting analytic technique, random intercept cross-lagged panel models (RI-CLPMs), to overcome the chicken/egg issue around marijuana use and mental health issues, i.e. do mental health issues lead people to use marijuana or does marijuana lead to mental health issues. This method looks for within-person differences to identify increased marijuana use preceding increased symptoms of psychosis and increased psychosis symptoms preceding increased marijuana use.

The participants in this study were grade 7 students (aged 13 at the start of the study) in the greater Montreal area. Survey data was anonymised and was collected over 4 years for 3720 adolescents. What the data showed was that teens who used cannabis in any given year had an increase in psychosis symptoms a year later. Having symptoms of psychosis is not the same as having a psychotic disorder, but they do increase the likelihood of developing a psychotic disorder.

Given these two recent studies, it seems that cannabis risks include psychosis in teens and death in some adults. So, while there is evidence for marijuana’s usefulness for pain, sleep problems, nausea, poor appetite, and some other issues, this natural remedy isn’t free from risks.


Bourque J, Afzali MH, Conrod PJ. Association of Cannabis Use With Adolescent Psychotic Symptoms. JAMA Psychiatry. Published online June 06, 2018.

Yankey BA, Rothenberg R, Strasser S, et al. Effect of marijuana use on cardiovascular and cerebrovascular mortality: A study using the National Health and Nutrition Examination Survey–linked mortality file. Eur J Prev Cardiol 2017.

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