Marijuana and Teens

marijuana-teenMarijuana is one of the most common drugs of abuse among teens. A mix of dried pieces of leaves, seeds, stems and flowers, marijuana is usually smoked by teenagers, but it can be ingested in baked goods and other food items as well.

Many parents believe that marijuana use among teens is relatively harmless, a “rite of passage” that many of them say they indulged in and survived without a problem. However, today’s marijuana strands have a much higher amount of THC (delta-9-tetrahydrocannabinol), the active ingredient in the drug, as compared to the versions available in the 1970s. In fact, the National Institute on Drug Abuse (NIDA) reports that, on average, today’s marijuana contains almost 10 percent THC.

Prevalence of teen marijuana use.
Marijuana is the most commonly used illicit drug in the United States, ranking just behind alcohol and tobacco as the most commonly used addictive substance among teens. Usage rates for high school students increased between 2009 and 2010 from 5.2% to 6.1% for high school seniors, 2.8% to 3.3% for 10th grade students and 1.0% to 1.2% for 8th grade students. In 2007, the majority of youth age 17 or younger entering drug abuse treatment programs said marijuana was the drug they used most often.

A study published in the journal Clinical EEG and Neuroscience reported that use of marijuana during the teen years negatively impacted:

  • Brain structure volume
  • Quality of white matter
  • Ability to perform cognitive function

According to the report, “The proportion of adolescents aged 12–14 reporting ‘strong disapproval’ of marijuana use initiation increased significantly from 74.4–78.9%. Concurrently, a significant decrease in past 12-month marijuana use … was observed among younger adolescents.” In that 12-14 age range, the percentage of those who had used marijuana in the past year decreased from 6 percent in 2002 to 4.5 percent in 2013. For older teens, from 15 to 17, disapproval of pot didn’t change, but the percentage of teens who had smoked weed in the previous year declined from 26 percent in 2002 to 22 percent in 2013.

Teen Development

teen-use-marijuanaUnlike adults, the teen brain is actively developing and often will not stop until the mid-20s. Drinking and drug use during this period can have a hugely detrimental impact, affecting your teen’s ability to progress and grow on numerous fronts, including:

  • Emotional development
  • Academic retention
  • Social interactions

How does this happen? The THC in marijuana affects the way that sensory information is processed by the hippocampus, part of the limbic system in the brain that controls learning and memory as well as the combination of sensory experiences with emotion and motivation. By suppressing the neurons in the hippocampus, THC causes learned behaviors to deteriorate; thus the teen’s ability to handle stimuli productively is stunted.

Mental Health Effects

Marijuana’s lasting effects on the brain impact both physical and mental health in teens. The Rhode Island state government reports that teen mental health can be impacted by frequent use of the drug in the following ways:

  • Doubles the risk of developing symptoms of depression and anxiety
  • Three times as likely to have suicidal thoughts as compared to peers who do not smoke marijuana
  • Increased risk of developing schizophrenia in later teen years

Why is mental and emotional development so hindered by marijuana use? In teens, the area of the brain responsible for emotion and memory is very well developed, but the area of the brain dedicated to judgment still needs time to mature. Marijuana use stops this growth, and those emotional highs and lows of the teen years can become overwhelming, resulting in mental health issues.

Marijuana’s effects on teenagers.

Marijuana causes a host of negative side effects for everyone, but regular marijuana use is particularly detrimental for young students. It decreases learning, judgment and motor skills and diminishes initiative and motivation. Clinical studies show that smoking marijuana leads to cognitive delays that can last up to 24 hours, causing reductions in one’s ability to concentrate, consolidate memories and develop verbal and mathematical abilities. In the long term, The National Institute on Drug Abuse (NIDA) warns that high rates of marijuana use place teenagers at risk for future brain development abnormalities.


Dr. Megan Bell




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