When Can Marijuana Be Harmful?

Marijuana is one of the most controversial and polarizing drugs available today. Its legacy in the U.S. is complicated. Marijuana arrests have been critical drivers in the war on drugs, accounting for 40% of all drug charges1. The federal government still classifies marijuana as a schedule I controlled substance, alongside drugs like heroin, LSD, and bath salts.

Marijuana’s reputation is not predominantly negative. Medical professionals have long advocated the benefits of weed for pain management and treating mental health conditions. Additionally, marijuana remains extremely popular among the public, with over 48 million Americans using it at least once2.

Many U.S. states have legalized weed for medicinal use, and nine states and the District of Columbia have fully legalized marijuana for recreational use. But the jury is still out on the drug; depending on who you ask, marijuana is either a “gateway drug” or a promising (and non-addictive) way to treat conditions from arthritis to HIV.

But what is the truth? Is marijuana harmful? Should people who use weed go to rehab, like others who seek drug and alcohol addiction treatment? Let’s look at some of the potentially bad effects of weed.

Is Marijuana Harmful to Your Body?

At Better Addiction Care, we are intimately familiar with how addiction can hurt your life, your relationships, and your body. We strive to help anyone struggling with addiction find a treatment program to help them recover. But is marijuana a drug that can truly be addictive?

According to research, yes. The National Institute on Drug Abuse (NIDA) reports that 30% of people who use marijuana develop a marijuana use disorder — which means they cannot stop using the drug, even when it negatively impacts their life3. Individuals with marijuana use disorder also experience withdrawal symptoms when they stop using marijuana, which suggests that weed can have negative effects on your health.

How harmful is weed? Here are just some of the ways it affects your body.

Negative Effects of Weed

Lung Health

Most people know that inhaling smoke harms the lungs (thanks largely to public awareness campaigns that discourage tobacco products). Smoking marijuana is one of the most common ways to consume the drug, so we must ask: is marijuana harmful to the lungs?

In a word: yes. Research shows that marijuana smoke contains many of the same toxins as tobacco smoke, including those that can cause lung cancer4. People who smoke marijuana may even face more exposure to these toxins than tobacco users because they typically inhale more deeply and hold the smoke in their lungs longer than those who smoke cigarettes or cigars.

However, it is important to remember that smoking is just one way to use marijuana. About 36% of daily marijuana users opt for edibles instead, which is generally considered a less harmful way to ingest weed5. A decline in smoking marijuana may help prevent lung problems, but that is far from the only bad effect of weed.

Bone Health

The way marijuana smoke affects the lungs may seem obvious to many users, which likely accounts for the recent rise in edible use. However, there are other harmful things weed can do to your body that often go unnoticed. For example, research shows that weed use can decrease your mineral bone density, putting you at an increased risk for bone fractures6.

Why does marijuana affect your bones? Because THC (the ingredient in marijuana that gets you “high”) activates the body’s CB1 receptors. Once activated, these receptors can inhibit bone production and harm your skeletal health.

Of course, it is important to note that the way weed affects your bone health depends largely on how much you smoke. Researchers typically connect bone density loss to “heavy use.” This suggests that the more you smoke or use edibles, the more likely you are to experience adverse health effects — and the better it will be to contact a private, free or funded rehab.

Heart Health

People use marijuana for many reasons, both recreational and medicinal. Among medicinal purposes, researchers have discovered that weed can benefit individuals with Parkinson’s disease, endometriosis, anxiety, nausea, and even PTSD. For this reason, groups like the Disabled American Veterans Organization work to make marijuana use acceptable in therapy programs and rehabs for veterans7.

However, marijuana will never be recommended to treat cardiovascular conditions. This is due to one simple reason: weed is harmful to your heart. According to Harvard Medical School, marijuana use raises your resting heart rate, dilates your blood vessels, and increases your blood pressure — all of which increase your risk of a heart attack8.

Admittedly, the cardiovascular risks associated with marijuana use are minimal for individuals who do not have a risk of heart disease. Unfortunately, about 18 million Americans have some form of heart disease, which means that many people might be taking a serious risk each time they use marijuana9.

Brain Health

Most people today are familiar with the “stoner” stereotype. This person uses marijuana daily (if not multiple times a day), have poor memory, and seem lazy or unmotivated.

Is there any truth to this stereotype? According to research, maybe. Studies conducted on rats found that marijuana use is directly connected to problems with learning and memory later in life, and studies on humans reveal a marked decline in IQ among people who start using marijuana in adolescence10.

These findings are troubling, but even more so are the results from a study on marijuana use and “cross-sensitization.” According to this study, rats exposed to THC demonstrated a heightened response when exposed to other drugs, like morphine10. This shows that long-term marijuana use changes your brain’s reward center by making you more sensitive to other drugs, crediting the idea that marijuana is a “gateway drug.”

Weed and Cancer

We’ve already discussed how marijuana use increases your risk of lung cancer. But according to some studies, that is not the only form of cancer connected to marijuana use. A 2019 meta-analysis of 25 studies reported an association between long-term marijuana use and the growth of testicular germ cell tumors11. Although the report concedes that the risk was low, individuals who use weed extensively should be aware of this risk.

Marijuana Use And Pregnancy

For many people, their individual health is not the only thing they must consider. A reported 4.2% of women use marijuana while they are pregnant12.

Smoking or taking edibles while pregnant can be hazardous for the developing fetus, leading to complications like low birth weight, pre-term birth, decreased brain development, and stillbirth13.

The THC in marijuana can also affect a woman’s breast milk, leading to problems with brain development for the nursing child. Therefore, it is vital that a woman who becomes pregnant stops using marijuana during her pregnancy and while nursing.

How Harmful is Weed?

Let’s examine our earlier question: Is marijuana harmful? Based on the information above, the answer is clearly “yes.” However, it’s also important to acknowledge that weed is only harmful when used in excess. People who are “heavy users” — which doctors classify as using every day or multiple times daily — have the greatest risk of suffering the bad effects of weed14.

How many Americans are “heavy users”? NIDA reports that 30% of people who use marijuana have a marijuana use disorder, suggesting an estimated 6 million people are putting their health at risk each time they consume marijuana — and it may not be easy for them to stop15.

Contact Better Addiction Care for Marijuana Addiction Help

If you believe that you or someone you love is suffering from dependence on weed, it’s important to get help from an addiction specialist as soon as possible. Better Addiction Care wants to help you connect with the right specialist for your unique needs. Our team can help you find a rehab facility that works for you to start your recovery journey on the right foot.

Our treatment advisors know that the right program is essential to your recovery. We’ll work with you to learn all we can about your medical needs, substance use history, recovery goals, insurance provider, and much more. Then, we’ll connect you with the addiction treatment center best fit for you! Before you know it, you’ll be on your way to recovery — and you’ll have plenty of support at your side.

Let Better Addiction Care be the helping hand you need to take that first step toward sobriety. Whether you’re looking for a place to attend court-ordered rehab, a private facility for a loved one, or you want more information about your treatment options; we are here to help 24/7.

Call us today at (800) 429-7690.


  1. Gramlich, J. (2020, January 22). “Four-in-ten U.S. drug arrests in 2018 were for marijuana offenses – mostly possession.” Pew Research. Retrieved June 3, 2022 from https://www.pewresearch.org/fact-tank/2020/01/22/four-in-ten-u-s-drug-arrests-in-2018-were-for-marijuana-offenses-mostly-possession/
  2. CDC. (2021, June 8). Marijuana and Public Health: Data and Statistics. CDC. Retrieved June 3, 2022 from https://www.cdc.gov/marijuana/data-statistics.htm#
  3. NIDA. (2020, July). Is marijuana addictive? National Institutes of Health. Retrieved June 4, 2022 from https://nida.nih.gov/publications/research-reports/marijuana/marijuana-addictive
  4. American Lung Association. (2020, December 17). Marijuana and Lung Health. American Lung Association. Retrieved June 4, 2022 from https://www.lung.org/quit-smoking/smoking-facts/health-effects/marijuana-and-lung-health
  5. Reboussin, B. et al. (2020, December 1). “Trends in marijuana edible consumption and perceptions of harm in a cohort of young adults.” Drug and Alcohol Dependence. Retrieved June 4, 2022 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7008857/#__ffn_sectitle
  6. O’Connor, C. et al. (2020, May 8). “Cannabinoid Use in Musculoskeletal Illness: a Review of the Current Evidence.” Current Reviews in Musculoskeletal Medicine. Retrieved June 5, 2022 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7340702/
  7. Hunter, M. (2018, November 6). The Cannabis Cure. Disabled American Veterans Organization. Retrieved June 6, 2022 from https://www.dav.org/learn-more/news/2018/the-cannabis-cure/
  8. Harvard Medical School. (2022, January 19). Marijuana and heart health: What you need to know. Harvard Medical School. Retrieved June 6, 2022 from https://www.health.harvard.edu/heart-health/marijuana-and-heart-health-what-you-need-to-know
  9. CDC. (2022, February 7). Heart Disease Facts. CDC. Retrieved June 6, 2022 from https://www.cdc.gov/heartdisease/facts.htm
  10. NIDA. (2020, July). What are marijuana’s long-term effects on the brain? NIH. Retrieved June 6, 2022 from https://nida.nih.gov/publications/research-reports/marijuana/what-are-marijuanas-long-term-effects-brain
  11. Ghasemiesfe, M. MD, et al. (2019, November 27). “Association Between Marijuana Use and Risk of Cancer: A Systematic Review and Meta-analysis.” Substance Use and Addiction. Retrieved June 6, 2022 from https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2755855
  12. Ko, J. PhD et al. (2020, August 14). “Characteristics of Marijuana Use During Pregnancy — Eight States, Pregnancy Risk Assessment Monitoring System, 2017.” Morbidity and Mortality Weekly Report. Retrieved June 6, 2022 from https://www.cdc.gov/mmwr/volumes/69/wr/mm6932a2.htm
  13. SAMHSA. (2022, April 27). Marijuana and Pregnancy. SAMHSA. Retrieved June 6, 2022 from https://www.samhsa.gov/marijuana/marijuana-pregnancy
  14. Powell, A. (2020, February 24). “What we know and don’t know about pot.” The Harvard Gazette. Retrieved June 6, 2022 from https://news.harvard.edu/gazette/story/2020/02/professor-explores-marijuanas-safe-use-and-addiction/
  15. Hasin, D. et al. (2015, December). “Prevalence of Marijuana Use Disorders in the United States Between 2001-2002 and 2012-2013.” JAMA Psychiatry. Retrieved June 6, 2022 from https://pubmed.ncbi.nlm.nih.gov/26502112/
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