Marijuana Use Linked to Consequences in Young Users

As cannabis research continues, scientists and researchers are finding many dangerous health complications intimately connected to cannabis.

Young woman in a hospital

Contrary to some narratives, cannabis is not harmless or safe. Experimenting with cannabis carries a variety of negative effects, and while most people are familiar with the short-term effects of cannabis, there is a body of new research that point to the serious long-term consequences of using this drug.

From increased risk for certain types of stroke complications to a higher likelihood for stroke events in young people, from memory loss to potentially permanent drops in IQ, people who use cannabis are putting their health at serious risk.

Increased Risk for Stroke Complications

Doctor pointing at x-ray

A January 2022 study focused on how, when people who use marijuana experience a particularly rare stroke, they are twice as likely to go through very serious complications from that stroke than people who do not use marijuana but who do experience a stroke. To be clear, the study does not say that people who use marijuana are more likely to experience a stroke than people who do not use marijuana. The study simply reports that people who do suffer a certain type of stroke while on marijuana are more likely to experience serious harm as a result.1

All Americans face some degree of risk for experiencing a stroke. But stroke events vary greatly in severity. Dr. Michael T. Lawton, the senior author of the study and the president and CEO of Barrow Neurological Institute, stressed that people who use marijuana are simply at more risk of experiencing serious and harmful outcomes of a stroke incident. In his own words, “We’re all vulnerable to a bleeding stroke or a ruptured aneurysm, however, if you’re a routine marijuana user, you may be predisposed to a worse outcome from a stroke after the rupture of that aneurysm.” From this, we can infer that a way to reduce the risk for severe stroke outcomes would be to abstain from using marijuana.2

Increased Risk of Stroke for Young People

This next set of research is still being assessed, but preliminary findings show there is reason to believe that young people who occasionally use cannabis are 1.8 times more likely to experience a stroke than young people who do not use cannabis. Further, young people who frequently use cannabis are 2.5 times more likely to experience a stroke than young people who do not use it.3

This research is backed up by another independent body of information that shows a link between young people who use cannabis, experience a stroke, and who then experience a second, repeat stroke. According to the separate data, young people who use cannabis and experience a stroke are 50% more likely to experience a second stroke than young people who experience a stroke but who do not use cannabis. It’s unclear how or why cannabis use would increase risk for repeat stroke, more severe stroke complications, or higher likelihood of stroke incidents in young people, but there does seem to be a connection.4

Cannabis Use a Potentially Permanent Detriment to IQ in Young People

College student having troubles

Emerging data shows a concerning connection between cannabis use and IQ, suggesting that using cannabis drops IQ a few points in young people. Further, the research indicated that those IQ points don’t necessarily come back, even if the person stops using cannabis. Professor Mary Cannon, one of the researchers who contributed to the findings, was quite concerned about the risks of young adults’ use of cannabis. In her own words, “Previous research tells us that young people who use cannabis frequently have worse outcomes in life than their peers and are at increased risk for serious mental illnesses like schizophrenia. Loss of IQ points early in life could have significant effects on performance in school and college and later employment prospects.” She went on to say, “Cannabis use during youth is of great concern as the developing brain may be particularly susceptible to harm during this period.” In the face of existing and known harmful side effects of youth cannabis use, new data on the risk for IQ-drop adds yet another harmful effect to the list.5

“Previous research tells us that young people who use cannabis frequently have worse outcomes in life than their peers and are at increased risk for serious mental illnesses like schizophrenia. Loss of IQ points early in life could have significant effects on performance in school and college and later employment prospects.”

The research published by Professor Mary Cannon and the RCSI University of Medicine and Health Sciences is backed up by information published by the National Institute on Drug Abuse.6 NIDA was hesitant to officially draw a direct cause and effect relationship between marijuana use and a permanent drop in IQ, but the institution did cite relevant research indicating that possibility. For example, NIDA referenced a New Zealand study that found adults who had begun using marijuana frequently in their adolescence were associated with a loss of an average six to eight IQ points when measured at mid-adulthood. Conversely, the research indicated that adults who had not used cannabis in adolescents but who did begin using the drug in adulthood did not experience a drop in IQ. Those findings suggest that marijuana can have potentially permanent, damaging effects on IQ when consumed during a young person’s critical, developmental stages of life.

Marijuana and Memory

An emerging body of research links heavy cannabis use with memory loss, particularly among young people. The same NIDA research cited in the previous section indicated that young people who use cannabis might experience memory loss. The NIDA researchers were again hesitant to draw a direct cause and effect relationship, but in their own words: “Some studies suggest regular marijuana use in adolescence is associated with altered connectivity and reduced volume of specific brain regions involved in a broad range of executive functions such as memory, learning, and impulse control compared to people who do not use.”6 Even if there is just a risk for memory loss, that should be enough to dissuade young people from experimenting with cannabis.

Though experts in addiction science and neurology are still hesitant to definitively claim that marijuana use causes memory loss, the biology of how this might occur is well known. The Harvard Medical School has written extensively on this, publishing a summary in November 2021 about marijuana’s effect on the brain. From that summary, “There’s no question that marijuana…can produce short-term problems with thinking, working memory, executive function, and psychomotor function…This is because marijuana’s main psychoactive chemical, THC, causes its effect by attaching to receptors in brain regions vital for memory formation, including the hippocampus, amygdala, and cerebral cortex.”7 Those concerned about keeping their memories intact should take this research as a warning of a potentially unwanted outcome and abstain from using marijuana.

Addiction Treatment is Needed for Those Who Struggle with Cannabis Addiction

There are real medical harms from experimenting with cannabis, no matter one’s age or when they began using the drug. Further, cannabis is addictive, and when people become hooked on this mind-altering substance, they will need professional help to stop using it and to abstain from using it.

If you know someone who is using marijuana and who cannot stop, please help them enter into a qualified drug and alcohol addiction treatment center today. Please don’t wait until it is too late for them, until their addiction worsens and they experience permanent harm from it.


  1. AHA. “Cannabis Use and Delayed Cerebral Ischemia After Aneurysmal Subarachnoid Hemorrhage.” 2022. ↩︎

  2. Science Daily. “Marijuana users’ risk of deadly complication doubles after rare type of bleeding stroke.” 2022. ↩︎

  3. Harvard Health Publishing. “Marijuana use linked to higher risk of stroke in younger adults.” 2020. ↩︎

  4. Medical News Today. “Young cannabis users at increased risk of repeat stroke.” 2022. ↩︎

  5. Science Daily. “Frequent cannabis use by young people linked to decline in IQ.” 2021. ↩︎

  6. NIDA. “What are marijuana’s long-term effects on the brain?” 2020. ↩︎ ↩︎

  7. Harvard Health Publishing. “The effects of marijuana on your memory.” 2021. ↩︎


After working in addiction treatment for several years, Ren now travels the country, studying drug trends and writing about addiction in our society. Ren is focused on using his skill as an author and counselor to promote recovery and effective …
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