I have written previously about some of the medicinal effects of the CBD (cannabinoid) component of marijuana. Despite the fact that cannabis is legal in most states of America and perceived to be harmless for recreational use, newer evidence has emerged showing that regular heavy use of cannabis causes a number of adverse health effects. Furthermore, it triggers cardiovascular complications of various types, and has even caused death, in young people.
THC (psychoactive) versus the CBD (medicinal) portions of marijuana (cannabis)
Delta 9-tetrahydrocannabinol (THC) is the psychoactive substance that is produced from marijuana. Its use for relaxation and euphoria is becoming more widespread since the decriminalization and legalization of cannabis began with Uruguay in 2012. This was done to replace links of organized crime to cannabis trade, with state regulation to allow for accountable and safe sale and distribution. Soon after this, Washington and Colorado States led the U.S. movement to legalize recreational cannabis. Yet its adverse effects are not being told.
Cardiovascular risk with marijuana use
Case reports of acute coronary syndrome (heart attack) and cerebrovascular episodesd (stroke) have been reported from marijuana use. When this occurs, it is more likely to occur during the first hour after marijuana inhalation.  Moreover, marijuana can aggravate heart vessel ischemia in patients with known coronary artery disease, potentially triggering a myocardial infarction. This is partially explained by the fact that there are endocannabinoid receptors in the heart.
Case studies can be illustrative. One case series identified three young patients in which marijuana use appeared to be the only cause of cardiac arrest. One of these patients was found collapsed at home in asystole (heart not pumping) and was resuscitated and taken to coronary angiography which showed a pronounced and diffuse arterial vasospasm. Two other patients were found to have occlusion of a coronary artery which caused ventricular fibrillation and were resuscitated by electrical cardioversion.
Marijuana smoking was also reported to be the likely cause of paroxysmal atrial fibrillation in a young female patient following marijuana intoxication.
Another case report identified a 21-year-old student with frequent inhalation of marijuana who was found to have multiple pauses in the heart beat lasting up to 5.8 seconds using a 24-hour Holter monitor. A repeat Holter was completely normal after he abstained from marijuana usage for 2 weeks, and again after 3 months. This provides other possible mechanism for sudden death seen in marijuana users who have no prior evidence of ischemic heart disease.
There are yet other case reports of unexpected death by cannabis intoxication in which full postmortem investigations (autopsy with toxicological, histological, immunohistochemical, and genetical examinations) excluded specific causes other than marijuana inhalation.
In one case series of cannabis-related stroke patients, 5 out of 17 patients suffered a recurrent event after they re-exposed themselves to marijuana.
In one study, French researchers analyzed adverse effects reported from marijuana use from 2006 to 2010. Of the 1979 reports, 35 were for cardiovascular complications. Eighty-five percent of the patients were men with mean age of 34.3 years. Of these complications:
20 were acute coronary syndromes (heart attack)
10 were peripheral vascular complications
3 were cerebrovascular (brain) complications
9 of these events led to patient death
In all this, it’s important to remember that the effect of cannabis is dose dependent. Also, know that the combination of alcohol with cannabis is likely to increase the cardiac toxicity of the THC component.
Other health problems with marijuana (cannabis) use
Let’s look at other significant health risks of cannabis use you may not have been told before.
Accident risk: significantly higher accident risk of drivers using cannabis. This was proven by measurable levels of Delta(9)-tetrahydrocannabinol (THC) found in the blood of injured drivers (in the absence of alcohol or other drugs) and also by surveys of “driving under the influence of cannabis,” and increased accident culpability of drivers using cannabis.
Schizophrenia: cannabis can precipitate the onset (or relapse) of schizophrenia based on large epidemiological studies linking the two.
Depression: a significant link between cannabis use and depression has been demonstrated in various cohort studies.
Precancerous lung changes: chronic inflammatory and precancerous changes in the lungs and airways of cannabis smokers has been demonstrated, which is proportional to the amount of cannabis used.
Cannabis dependence: both behavioral and physical cannabis dependence occurs in 7-10% of regular users. Daily and even weekly use are strong predictors of future dependence.
Cognitive impairments: during acute cannabis intoxication there are clearly cognitive impairments seen, but we cannot prove yet that permanent or even long-lasting functional losses result from chronic heavy cannabis use in adults.
Congenital abnormalities: the offspring of some women who used cannabis during pregnancy have been found to have higher risk of subtle yet permanent effects on their memory and information processing capabilities.
We now can see that cannabis has the potential for some serious adverse effects, and we will expect to see more of them as cannabis use becomes more widespread.
I know that we all want to be happy. I recommend to my patients to avoid taking any drug if you can find happiness in better, healthier ways.
To healthy ways to feeling good,
Michael Cutler, M.D.
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