Long-Term Effects on the Body
People who smoke marijuana tend to pull in deep breaths of smoke and hold that smoke in their lungs for long periods of time. People who use marijuana in conjunction with tobacco could be exposing their lungs to dangerous amounts of carcinogens as a result of this practice. Even people who do not use tobacco with their marijuana could face a higher risk of chest colds and chronic coughs due to the constant exposure of smoke to their lungs.
The NIDA also reports that smoking marijuana can cause serious long-term damage to the heart. The drug increases heart rate 25 to 100 times, and it can cause some people to experience a skipping, jittering, out-of-control heart rhythm. People who have existing heart conditions may be at particular risk for this side effect, and it’s possible that some people could have heart abnormalities and not even know it. These people could be exposing their heart to damaging chemicals, making their underlying problem even worse.
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Long-Term Effects on the Mind
While these bodily side effects might be frightening, the mental risks of marijuana abuse are far more extensive and can be much more severe. For example, a study published in the journal The Lancet found a clear link between chronic use of marijuana and the mental illness schizophrenia. People who used marijuana on more than 50 occasions had a much higher risk of developing schizophrenia than did people who had used marijuana fewer than 50 times. That risk persisted, even when researchers controlled for other mental illness risks and economic status. In other words, marijuana use and this mental illness are closely linked. Researchers aren’t yet sure why this link exists, and more work is ongoing on this issue.
Chronic marijuana use has also been linked to a wide variety of other mental illnesses, including depression. A study published in BMJ found that daily use of marijuana resulted in a five-fold increase in the risk of depression in young adults. Weekly use of marijuana resulted in a two-fold increase in the risk of depression. Interestingly, the researchers also attempted to discern if these young adults used marijuana because they were depressed. In other words, they tried to discern if the link was there because people who are depressed used marijuana to help with their depression or if marijuana use itself caused the depression. Researchers found no link between depression scores and later augmented use. It seems that the depression was caused by the drug use.
In addition to serious and chronic mental illnesses, marijuana use has been linked to cognitive declines. People who abuse marijuana slow down the speed and function of their minds, and they may be working at an impaired level of cognition most, if not all, of the time. One study, published in the Journal of the American Medical Associationfound that people who used marijuana over a long period of time performed worse on tests of memory and learning than people who did not use marijuana. The poor scores on the test were directly correlated with the length of time the person used marijuana. In other words, the longer the person used the drug, the worse score the person got on the test. It’s clear that marijuana can have a serious impact on the brain’s ability to function properly.
Marijuana has also been linked to a form of apathy, particularly in young people. Smoking marijuana seems to make people feel disconnected, sedated and unable to work up the energy to achieve a goal. It’s possible that the underlying mental illnesses caused by marijuana use, combined with the lower level of brain activity caused by marijuana, could stand behind this lack of motivation. But, it’s also possible that this is a separate mental illness altogether.





