Close to half of all states in the United States have passed laws in recent years allowing the use of marijuana as a medicine when a prescription from a doctor is obtained. Two states, Colorado and Washington, now allow cannabis for recreational use, meaning that no doctor prescription is required for its purchase or consumption. Yet, confusingly, marijuana use or possession is still illegal under federal law.
Many people may wonder if the government should have ever made the drug illegal, in the first place; it’s a natural herb that causes only mild, temporary cognitive effects in most infrequent or moderate users. Just like drinking alcohol, as long as someone isn’t driving, using heavy equipment or engaged in an activity requiring clear concentration, there is no real harm from occasional use of marijuana for most people.
In view of that, it would seem much more constructive — and far more cost-effective — to educate the public about the possible medical risks of excessive, frequent and long-term use.
And there are medical risks — though oddly enough, we seldom hear about those.
Studies have found that even among young adults, smoking marijuana poses risks to one’s health, albeit small, in the hours following use, and over time, if the use is frequent.
Marijuana Use and Stroke Risk
One study from New Zealand found that marijuana use may increase the risk of stroke. The study, presented at the 2013 American Stroke Association’s International Stroke Conference, examined urine samples from 160 people between the ages of 18 and 55, who had suffered strokes.
Researchers found that these stroke victims were twice as likely to have cannabis in their urine, compared to members of a control group, who had visited the hospital for reasons not related to stroke. Among the stroke patients, 16 percent had cannabis in their system, compared to 8.1 percent of the control patients.
Of the 160 stroke victims, 150 had suffered “ischemic” strokes and 10 had had a transient ischemic attack (TIA).
Strokes are caused by a disruption of blood flow to the brain. Eighty-seven percent of all strokes are ischemic (source: American Stroke Association). In a heart attack, clots or plaques in the coronary arteries block blood flow to a section of the heart; likewise, in an ischemic stroke, clots or plaque deposits on the linings of arteries feeding the brain block blood flow and oxygen to a section of the brain. This is different from the less-common hemorrhagic stroke, where a blood vessel in or around the brain ruptures; hemorrhagic strokes account for the lesser 13 percent of all strokes.
A TIA, also called a mini-stroke, is when a person experiences stroke symptoms that go away a few minutes later, without leaving any lasting damage; one-third of all people who suffer a TIA go on to have a stroke within a year (source: American Heart Association).
Study author Dr. Alan Barber, professor of clinical neurology at the University of Auckland in New Zealand, noted that he knew of case reports of people with no other vascular risk factors, having a stroke or TIA within hours of having smoked marijuana. In his study, however, all but one of the patients who had marijuana in their system and had suffered a stroke were also tobacco users. Still, Barber believed that marijuana was behind the strokes, being that many of the cannabis-using stroke victims were fairly young; in addition, some of them suffered their strokes while they were smoking marijuana.
Symptoms of stroke include:
- Severe headache
- Numbness or weakness in the face or limbs, especially on one side of the body
- Confusion, trouble speaking or understanding
- Sudden vision problems
- Trouble walking, dizziness, loss of coordination
Close to 800,000 Americans suffer a stroke each year, with 130,000 dying from it. While most victims survive stroke, it is the number one cause of permanent disability in the United States.
Marijuana Use and Arrhythmias
Johns Hopkins Medicine reports online that marijuana use is associated with a risk of developing heart arrhythmia. An arrhythmia is when your heart beats too fast, too slowly or irregularly. Different factors can cause arrhythmias, including diseases of the heart or its valves, thyroid disorders, some anti-arrhythmia drugs, stimulants like caffeine, excessive alcohol consumption and overdoses of cocaine, marijuana or antidepressants.
Smoking marijuana increases heart rate from 20-100 percent for up to 3 hours after use; this may or may not be connected to reversible heart rhythm disturbances (arrhythmias) following marijuana use that have been seen in studies. (Source: National Institutes of Health.)
Arrhythmias have a wide range in their level of seriousness; they may be relatively harmless if they only occur on occasion, they may require medical treatment if they happen often, or they may be life-threatening and require immediate medical attention if they’re continual.
Heart palpitations or arrhythmia also increase a person’s risk of stroke. When the heart beats irregularly, even if the beats occur much faster than normal, the heart’s upper chambers, the atria, don’t fully pump out all incoming blood into the lower chambers, the ventricles; blood can then pool in the upper chambers, and blood clots can form, which can be carried in the blood to the brain’s arteries, resulting in a stroke.
Symptoms of serious arrhythmias include:
- Ongoing palpitations or irregular-feeling heart beats
- Shortness of breath
- Chest pain
- Mental confusion
- Dizziness, fainting or loss of consciousness
If you experience any of these symptoms, call or see a health care professional right away.
Arrhythmias can also be “silent” and produce no symptoms; however, an irregular heartbeat can be detected by a doctor during a physical exam or through screenings. Seek medical advice if you have any questions about an arrhythmia or any other heart issues.
Marijuana Use and Heart Disease
Some American health authorities have observed that the numbers of people who have suffered cardiovascular problems as a result of smoking cannabis are probably under-reported, due to the drug being illegal, and some medical experts have called on governments to do more, to educate people about possible risks of marijuana use and abuse.
A small French study published in April, 2014 in the Journal of the American Heart Association concluded that marijuana use may contribute to heart and artery disease in young and middle-aged adults, and that those who are already at risk for cardiovascular events should be especially concerned about effects the drug may have on them.
Researchers examined cases of marijuana abuse in France reported between 2006 and 2010; they reviewed medical records for 1,979 people who were reported by doctors during the 5-year period as abusing marijuana. Most of these heavy cannabis users were male; average age was 34.
Thirty-five in the group had experienced cardiovascular problems: twenty had had heart attacks, 10 had arterial disease in their limbs, and 3 had had problems in brain arteries. There had been 9 deaths among the 35 cases. In 46 percent of the cases (16 out of the 35), the patients had risk factors for heart disease, such as high blood pressure or high cholesterol, or a family history of cardiovascular disease.
The percentage of heart disease cases more than tripled during the 5-year study period, from 1.1 percent to 3.6 percent.
Marijuana Use and the Lungs
It’s smart to also remember that using marijuana, even when it’s not smoked, puts chemicals into one’s system that give the body’s cells more work, to keep things clean and running smoothly. But smoking cannabis is especially bad for the lungs; studies have shown that smoking marijuana produces almost three times the level of tar that’s inhaled into the lungs when smoking cigarettes. In addition, studies have shown that marijuana smoke has up to 70 percent more cancer-causing compounds than cigarette smoke. Those are things to consider, especially given that cannabis smokers inhale the smoke deeper and hold it longer than cigarette smokers.
That said, with respect to lung function, studies have found that cigarette smokers fare worse than cannabis smokers. One study that measured lung function in more than 5,000 cannabis smokers over 20 years found that smoking marijuana long-term at “low” levels (defined as one joint a day for 7 years or one a week for 20 years) did not result in diminished lung function. (Source: Journal of the American Medical Association.)
This last point is in contrast to the harm that cigarette smoking is well-known to cause to smokers’ lung function. As for people who use cannabis as well as tobacco, health experts believe that there may be compounded risks.
By Cynthia Sanchez. A graduate of the University of Washington, Cynthia has extensive experience writing about health and wellness topics for different media.