Dangers of Using Marijuana in Adolescence

Recent Trends in Teen Marijuana Use

Marijuana use among teens has been increasing over the past few decades, reflecting broader shifts in cultural attitudes, accessibility, and perceived risk. A 2022 study found that 30.7% of 12th graders in the U.S. reported using marijuana within the past year, and 6.3% said they had used it daily over the previous 30 days⁠^[1].

CDC’s 2024 summary reports that, in the 2022 Monitoring the Future survey, 30.7% of U.S. 12th graders reported cannabis use in the previous year and 6.3% reported daily use in the previous 30 days. These are dated survey estimates, not a measure of current use⁠^[1].

These rising usage rates do not just reflect access or availability; they also point to a more profound shift in how teens think about marijuana and the role it plays in their lives. What was once considered a dangerous behavior is now increasingly seen as a normal part of adolescence. 

Lower Perceived Risks of Marijuana Use

The rise in adolescent marijuana use is closely linked to a dramatic shift in how teens perceive its risks. In 1992, 80% of 17- to 18-year-olds considered marijuana use to be a "great risk," but by 2002, that figure had dropped to 45%.

This sharp decline in perception over just a decade suggests a significant shift in societal attitudes toward marijuana use. It could help explain the corresponding increase in usage⁠^[2].

A key factor driving this change is the ongoing legalization of marijuana in various U.S. states, which has helped normalize its use in the eyes of the public. With less stigma attached, marijuana is increasingly seen as less harmful, especially by young people. This shift is further amplified by its portrayal in media, where marijuana use is often depicted as casual or even glamorous.

As marijuana becomes more entwined with youth culture and mainstream media, teens may feel less deterred by its potential risks. When the dangers of marijuana use are downplayed or obscured by positive portrayals in the media, it's easier for young people to underestimate the real impact it can have on their health. 

The reduction in perceived risk plays a crucial role in the increasing prevalence of marijuana use among teens.

Adverse Effects of Marijuana on Cognitive Health

Marijuana can harm health and well-being of a person at any age. However, adolescents are at greater risk because their brains are still developing. The human brain continues to mature through the teenage years and doesn't fully finish this process until around 25.

During adolescence, the brain undergoes rapid changes that help form the neural pathways needed for efficient thinking, decision-making, and emotional regulation, all crucial in adulthood. When adolescents use marijuana, it can disrupt this development, leading to impairments in memory, attention, and learning⁠^[1].

Cannabis use during adolescence may affect a developing brain. Reported concerns include attention, memory, learning, and mental health. Associations with psychosis are stronger with earlier and more frequent use, although an association does not mean every person will develop a disorder⁠^[1].

Short-Term Effects of Marijuana Use

Short-term marijuana use can have a range of immediate effects, many of which can negatively impact both daily functioning and long-term development for teens and adolescents. 

Short-term effects of marijuana use can lead to⁠^[3]:

• Memory and Concentration Issues: Using marijuana at any age can impair short-term memory and concentration, and this is especially true for adolescents. Their brains are still developing and rely on memory and concentration for academic and social development. In daily life, this can show up as struggling to complete homework tasks or difficulty retaining new information presented in class. 

• Increased Aggression: Some teens may experience increased aggression or irritability when using marijuana. Since adolescents are still learning how to regulate their emotions, marijuana use can intensify mood swings and make it harder to manage stress. This may lead to conflicts with friends, family members, or teachers.

• Risky Sexual Behaviors: Marijuana can impair judgment and inhibitions, leading adolescents to engage in risky behaviors like unprotected sex or making impulsive decisions they later regret. These behaviors can also lead to unintended consequences, like a sexually transmitted disease or an unplanned pregnancy. 

• Increased Risk of Mental Illness: While mental health conditions can develop at any age, marijuana use during adolescence heightens that risk. Acute marijuana use can trigger symptoms of anxiety, paranoia, and, in extreme cases, psychosis or schizophrenia. Adolescents who have a family history of mental illness may be extra vulnerable, as marijuana use can act as a trigger for underlying conditions. 

• Worsening Mental Health Conditions: Teens already struggling with anxiety or depression may find that marijuana use worsens their symptoms. Although using marijuana can provide temporary relief from these feelings and symptoms, they usually worsen after the effects wear off. Relying on marijuana to cope can make it harder to develop more effective strategies for managing difficult emotions⁠^[4].

Considering the many changes adolescents experience during their formative years, it’s important to understand the impact cannabis has on mental health. In fact, in some cases, it can have long-term consequences. 

Long-Term Effects of Marijuana Use

While occasional marijuana use may seem harmless to some, long-term use can lead to serious health problems like cannabis use disorder (CUD), respiratory issues, and cognitive decline. 

More frequent use and starting in adolescence are associated with a greater risk of cannabis use disorder. Possible difficulties include:⁠^[1]

• Cannabis Use Disorder (CUD): Regular marijuana use can lead to dependence, which manifests as marijuana cravings, difficulty controlling usage, and experiencing withdrawal when not using. CUD can negatively affect daily life, including work, school, and personal relationships.

• Breathing Difficulties: Chronic marijuana use can cause respiratory issues such as coughing, wheezing, and an increased risk of lung infections. Similar to tobacco smoking, long-term marijuana smoking can damage the airways and pose a higher risk for contracting lung cancer later on in life.

• Decreased Motivation or Interest: Known as "amotivational syndrome," prolonged marijuana use among teens can result in reduced motivation and a lack of interest in hobbies and activities they once enjoyed.

• Lower IQ: Research indicates that regular marijuana use during adolescence can lead to a decline in IQ, particularly in those who begin using at an early age. The impact on cognitive function may be long-lasting⁠^[2].

• Increased Mental Health Risks: Long-term marijuana use is linked to a higher risk of developing mental health conditions like anxiety, depression, and psychosis. Adolescents who use marijuana heavily are particularly vulnerable to these health risks, which may worsen over time. 

Misconceptions about Marijuana

Educating adolescents about the dangers of using marijuana is a good way to counter beliefs and reduce recreational use of the drug. There are three common misconceptions that lead many adolescents to view marijuana as safer than alcohol or other drugs. 

Misconceptions about marijuana use include:

• Marijuana isn’t Addictive: Marijuana can be, and often is, addictive among users of all ages. Approximately 3 in 10 people who use marijuana develop cannabis use disorder. This condition may require treatment such as therapy, drug rehabilitation, and ongoing support. Individuals who begin using marijuana during adolescence are at higher risk for developing a dependence on the drug. 

• No Long-Term Effects: Some believe that marijuana usage does not have any long-term effects. However, there are several long-term effects of marijuana usage. For example, deficits in learning and processing speed, altered brain development, poor educational outcomes with increased likelihood of dropping out of school, and symptoms of chronic bronchitis are just a few of the known effects teens experience with long-term marijuana usage. 

• Natural Means Safe: While it’s true that marijuana is a plant, not all natural substances are safe. Plants and naturally occurring substances are often harmful or even deadly when consumed. The chemical makeup of recreational marijuana has also changed significantly over the last decade. Levels of THC, which is the compound responsible for marijuana’s psychoactive effects, have increased, while levels of CBD, the marijuana compound believed to offer the most medicinal benefits, remain at about 1%. 

Adolescents and Marijuana Use Going Forward

Marijuana remains the most commonly used illicit drug among teens in the U.S., with recent data showing that an increasing number of adolescents have tried it at least once, many using it more regularly⁠^[1]. Legalization in several U.S. states, along with more relaxed and often positive portrayals of marijuana in movies and TV shows, has contributed to this upward trend.

While marijuana can affect individuals of any age, adolescents are particularly vulnerable to its short- and long-term effects. Because the brain is still developing during the teenage years, marijuana use can interfere with memory, concentration, and emotional regulation. Ongoing use may also lead to addiction, reduced motivation, and an increased risk of developing mental health disorders.

Misconceptions about marijuana continue to shape how teens perceive occasional or recreational use. As the legal market expands, newer products often contain significantly higher levels of THC than in the past, and this often goes unnoticed. Educating teens about the risks of marijuana is key to challenging common myths and encouraging healthier choices.

Subject matter expert

Holly Schiff Psy.D.

Children, adolescents, and families

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