Marijuana: What Parents Need to Know

Julie Fenn, LICSW

By Julie Fenn  |  The website recently reported that 90% of addictions start during teenage years. 9 out of 10 people, who meet the medical criteria for drug or alcohol abuse or dependence, start smoking, drinking or using other drugs before the age of 18 years. Recently, The Lexington Public Schools sponsored a forum on marijuana. Teenage marijuana use has steadily risen in correlation to the 2008 Massachusetts referendum decriminalizing possession of small amounts of Marijuana. The 2009 Centers for Disease Control’s Youth Risk Behavior Survey reports that Massachusetts’ youth marijuana rates are already nearly 30% higher than national rates. Lexington alone has seen a steady increase over the last 3 years. Those of us working with teens have seen an alarming increase in teens seeking treatment for marijuana use. With the current research on marijuana, it’s important to have an accurate understanding of why the teen brain is so vulnerable to marijuana, know the alarming effects marijuana has on learning, emotional development; it’s addictive nature and toxic effects on the other organs in the body. Teen Marijuana use not only impacts a student’s physical and emotional health but also lowers the ambition and potential of many bright and talented youth.


Some parts of the brain are not fully developed until the mid-20’s, including the brain’s center for judgement, self-control, planning, learning and decision-making (frontal lobe). This leaves teens especially vulnerable to making quick, often risky, impulsive choices.

The teen brain’s emotional center is functional but not well controlled, making teens more susceptible to unpredictable behavior and vulnerable to peer pressure. We know that the teen brain is tuned for making fast responses and for quickly acquiring new information. Drugs and Alcohol can “hijack” the brain’s development, increasing risk for brain rewiring and addiction. Drugs change the connections in the adolescent brain, sometimes permanently.

It’s important to note that teens feel more of a high than adults when they have pleasurable experiences, while at the same time not feeling impaired as quickly as adults. (teens don’t feel impaired even though they are). This leads to more risk of becoming hooked more quickly than the adult brain.

The longer a teen postpones their first use, the less likely they are to have a problem. The beauty of the adult brain is that if we keep a cool head, we can filter through all the facts and influences to help our children see the “big picture” and make safer choices. Most recent data shows that more 15-17 year olds are in treatment for marijuana dependence than all other illegal drugs combined. Risk of becoming dependent on marijuana is 4 times greater for first use at age 13 than for first use age 21 or older. Teens who smoke marijuana have a much higher risk of developing a mental illness than those who start as adults, doubling the risk of depression and anxiety disorders.

THC, the primary drug in marijuana impacts the memory center of the brain. This affects learning. Teens who use marijuana one or more times a week report difficulty concentrating and problems with memory. Marijuana has similar cancer causing chemicals as tobacco. Marijuana users are treated for the same chronic respiratory diseases as tobacco. Chronic marijuana exposure can affect the reproductive systems of both males and females, disrupting the regular production of hormones. Use can lower fertility of both males and females

Marijuana use is now linked to increased risk of an aggressive form of testicular cancer among adolescent and young adult males. (“Association of Marijuana Use and the Incidence of Testicular Germ Cell Tumors,” by Daling and Schwartz, The Fred Hutchinson Cancer Research Center) Current studies are looking at the effects on the female reproductive system and ovarian cancer for similar links.

Many of us grew up with the Marlboro Man and positive images for smoking/chewing tobacco. For years many adults chose not to heed the warnings regarding the dangers of teen tobacco use. It is clear from the research that we cannot be complacent about teen marijuana use and it’s availability to younger and younger children. Marijuana is more harmful than people think. Changes in attitude lead to changes in use. (The Monitoring the Future study, The University of Michigan study.)

Parents and the Lexington community need to send a strong and clear message that marijuana use is not only dangerous but is a growing public health problem.



  • Educate yourselves about the harmful effects and the laws.
  • Talk often to your teens about the dangerous consequences.
  • Teach them problem-solving skills and how to resist peer pressure.
  • Know your child’s friends, where they live and who their parents are. Supervise and monitor your teens.
  • Teach healthy coping strategies/skills and make sure they have trusting adults in their lives that they could go to.



  • NIDA-the national institute on drug abuse

 Sources used in preparation of this article include: SAMHSA Drug Abuse Warning Network, 2008; Center for Adolescent Substance Abuse Research, Children’s Hospital Boston.

Julie Fenn is an LICSW, as well LPS Prevention Specialist/Health Educator. She has worked with Children, Adolescents and Families for 30 years and is the parent of 3 daughters.

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