Adolescent marijuana use and anticipatory guidance: What does the evidence support?

Contemporary PEDS JournalVol 38 No 4
Volume 38
Issue 4

Over the past 9 years, a number of states have legalized the recreational use of marijuana in adults aged 21 years and older. Although teenagers aren't legally allowed to consume the substance, the legalization for adults can make it more available to teenagers and young adults. This article covers the latest evidence and offers recommendations for talking to teenagers.

Even though marijuana, or cannabis, has been identified as the most commonly used illicit drug in the United States,1 in 2012, it was legalized for nonmedical, recreational use among adults aged 21 years old and older in Colorado and Washington State.2 Since then, 15 states and Washington DC, also legalized recreational marijuana use for adults and 36 states legalized medical marijuana.3 After its legalization, several studies were conducted to determine any changes in the use of marijuana among adolescents and college-aged students. A study in Oregon looked at data from adolescents who participated in Student Wellness Surveys in 35 counties (N= 247,403) in 6th, 8th, and 11th graders. The investigators concluded that the legalization and retail availability of recreational marijuana in the state were positively associated with marijuana use among adolescents.4 In another study conducted after the legalization of marijuana in 8 states, investigators examined 2 nationally-representative surveys, the Monitoring the Future and the National Survey on Drug Use and Health, administered to 12th grade students to determine trends in the prevalence of perceived no risk of harm in using marijuana on a regular basis and the prevalence of marijuana use.5 The investigators concluded that there was a resultant increase in the adolescents’ perception of no harm to using marijuana. However, there was not a concurrent increase in use in marijuana among the adolescent population.5

Stronger product, greater consequences

In 2019, the Surgeon General’s report detailed changes in concentration of delta-9-tetrahydrocannabinol (THC), the primary psychoactive ingredient in marijuana, from 1995 through 2014 that revealed a 3-fold increase in drug concentration, making the product much stronger.1 A national internet survey on drug use and health conducted by the US Department of Health and Human Services revealed that 18% of persons aged 12 years or older reported using drugs within the month prior to the survey and 1.5% of these adolescents met the criteria for cannabis use disorder.6 In addition, research studies on cannabis use during the adolescent years provide evidence for an altered trajectory in adolescent brain development and that this alteration may persist into adulthood, even following marijuana abstinence for several decades during the adult years.7,8 A study of 158 men aged 20 years, whose cannabis use was tracked during adolescence, showed a negative pattern of brain function. This was linked to higher levels of depression and mood symptoms and lower levels of attention, decision-making, educational achievement, memory, and motivation.9,10

The effect of prenatal drug exposure

Another study revealed that marijuana use in a person’s teenaged years may be a result of what happened in utero. Investigators examined the association between prenatal cocaine exposure (PCE) and adolescent substance use and hypothesized that alterations of neurotransmitter systems because of PCE affected fetal brain development and onset of substance use disorders during adolescence.11 Study results showed that adolescents with PCE were 2 times more likely to use tobacco and marijuana and have a substance use disorder at age 17 years compared with 17-year-old adolescents who were not prenatally exposed to cocaine.11 The availability and access to tobacco, marijuana, and alcohol during the adolescent years presents unique problems among pregnant and parenting adolescents. Two hundred and fifty-five pregnant adolescents, with a mean age of 16 years, participated in a study that tracked their substance use behaviors, as well as their intentions, attitudes, and beliefs about substance use, from pregnancy to 12 months’ postpartum.12 The investigators documented patterns of low-level use of cigarettes, marijuana, and alcohol during pregnancy and increased substance use in the first 6 months’ postpartum. They concluded that study participants were concerned about their infant’s well-being during pregnancy resulting in less substance use. However, the adolescents returned to their usual pattern of substance use in the postpartum period based on their perception that perceived social norms and attitudes towards substance use in the postpartum period was not opposed by friends, boyfriends, and siblings.12

Screening for substance use

Speaking with adolescents about substance use is a major tenet of pediatric practices whether the adolescent presents to a pediatric primary care office, a school-based health center, an urgent care center, an emergency department, a prenatal office, or a family health care center, including Federally Qualified Health Centers. Creating a safe environment for all adolescents to openly talk with the provider about substance use is the critical first step in creating the foundation for a meaningful conversation with adolescents. Assurance of confidentiality between provider and adolescent is essential and should be clearly explained by the provider at the beginning of the encounter based on individual state law mandates. The American Academy of Pediatrics recommends universal screening in pediatric primary care settings for substance use.13

There are 2 reliable and valid evidence-based substance use screening tools that can be integrated into the electronic medical record. The Screening to Brief Intervention and Brief Screener for Tobacco, Alcohol, and other Drugs tools can be completed in 2 minutes.13 Both tools screen for substance use within the past year and can be completed privately on a tablet by the adolescent while waiting to see the provider or by the provider in a face-to-face encounter with the adolescent.13 The CRAFFT Screening Interview tool, which is specifically designed for adolescents, can also be used to determine substance use by adolescents.13 The adolescent’s responses to whichever tool the provider selects must be evaluated by the provider and, if the adolescent has a positive screen, then it is imperative that a specific plan for action must be established by the adolescent and the provider on that day with appropriate follow-up plans in place.

Opening the conversation with parents

The provider should then address the substance use with the adolescent’s parents. But how does that conversation begin? First, the provider needs to ask the parents about their personal use of marijuana. If the parent or parents are marijuana users, then a provider should ask whether the adolescent is aware? Parental use of marijuana, in the more concrete thought patterns of preteens and younger adolescents, may provide silent permission for them to also use marijuana. Have the parents considered how their child feels about their use of marijuana? Does the adolescent have access to marijuana in their household? These may be difficult and uncomfortable conversations, but providers must ask them if they are to help the parents and their adolescent patients navigate this new world of legalization of recreational marijuana.

A good starting point is to provide evidence-based educational resources for parents on marijuana use in adolescents. Parents may not know that, according to literature, parental marijuana use is associated with an elevated risk of substance use among adolescent and young adult children living in the same household.14 Furthermore, the evidence shows that parental marijuana use in households with adolescents and young adults, that marijuana is a gateway drug for broader substance use including tobacco, alcohol, and opioids.14 Parental knowledge is key. They must know that their behaviors are placing their pre-adolescents and adolescents at risk for decreased brain growth and possible problems with the law. No states have legalized recreational marijuana use for anyone aged younger than 21 years. Parents are role models and encouraging parents to consider all the evidence about substance use in adolescents is step 1 for parents who use recreational marijuana on a regular basis in their homes.

For parents who do not use marijuana, the recommendations below addressing the health care providers role in speaking with adolescents can also be used by parents. It is important for parents to speak with their adolescent(s) in generalities that doesn’t accuse them of using marijuana, other drugs, or alcohol. Providers can suggest that parents use the approach of the CRAFFT tool to begin the conversation. The first question: Have you ever been with a friend or ridden in a car driven by someone who was high or had been using alcohol or drugs? This opens conversation in a non-threatening manner and allows opportunities to listen and provide parental guidance that can help their adolescent avoid dangerous substance use situations.


Whether an adolescent tests positive or negative for substance abuse, it is highly recommended that the adolescent-provider conversation about the topic become a routine part of health care. Providers have a unique opportunity to influence adolescent behaviors via a meaningful conversation that elicits the adolescent’s knowledge base about substance use, personal feelings, and ways to avoid the allure of engaging in substance use. Providers can engage adolescents in insightful conversations about substance abuse, the detrimental effects on brain growth, and the health and well-being of adolescents and young adults. If a provider’s busy schedule does not permit the allocation of time to converse about this topic, then providers may consider having a substance abuse office-based champion who will engage each adolescent in these most important conversations.


  1. Adams J. U.S. Surgeon General’s Advisory: Marijuana Use and the Developing Brain. August 29, 2019. Accessed February 20, 2021.
  2. Mason WA. Recreational marijuana legislation: What parents and adolescents know and discuss. Psychological Science Agenda. American Psychological Association. Accessed February 20, 2021.
  3. Berke J, Gal S, Yeji, JL. All the states where marijuana is legal — and 5 more that voted to legalize it in November. Business Insider. Accessed February 26, 2021.
  4. Paschall MJ, Grube JW. Recreational marijuana availability in Oregon and use among adolescents. ­Am J Prev Med. 2020;58(2):e63-e69. doi:10.1016/j.amepre.2019.09.020
  5. Sarvet AL, Wall MM, Keyes KM, et al. Recent rapid decrease in adolescents’ perception that marijuana is harmful, but no concurrent increase in use. Drug Alcohol Depend.2018;1(186):68-74. doi:10.1016/j.drugalcdep.2017.12.041
  6. National survey on drug use and health. Substance Abuse and Mental Health Services Administration. 2018. Accessed February 26, 2021.
  7. Crews F, He J, Hodge C. Adolescent cortical development: a critical period of vulnerability for addiction. Pharmacol Biochem Behav. 2007;86(2):189-199. doi:10.1016/j.pbb.2006.12.001
  8. Jager G, Ramsey NF. Long-term consequences of adolescent cannabis exposure on the development of cognition, brain structure and function: an overview of animal and human research. Curr Drug Abuse Rev. 2008;1(2):114-123. doi:10.2174/1874473710801020114.
  9. Lichenstein SD, Musselman S, Shaw DS, Sitnick S, Forbes EE. Nucleus accumbens functional connectivity at age 20 is associated with trajectory of adolescent cannabis use and predicts psychosocial functioning in young adulthood. Addict Abingdon Engl. 2017;112(11):1961–1970. doi:10.1111/add.13882
  10. Meruelo AD, Castro N, Cota CI, Tapert SF. Cannabis and alcohol use, and the developing brain. Behav Brain Res. 2017;325(Pt A):44–50. doi:10.1016/j.bbr.2017.02.025.
  11. Minnes S, Min MO, Kim J-Y, et al. The association of prenatal cocaine exposure, externalizing behavior and adolescent substance use. Drug Alcohol Depend. 2017;176: 33-43. doi:10.1016/j.drugalcdep.2017.01.027
  12. Morrison DM, Spencer, MS, Gillmore, MR. Beliefs about substance use among pregnant and parenting adolescents. Journal of Research on Adolescents: The Official Journal of the Society for Research on Adolescence. 1998;8(1):69-95. doi:10.1207/s15327795jra0801_4.
  13. Knight J, Roberts T, Gabrielli J, Van Hook S. Adolescent Alcohol and Substance Use and Abuse. Performing Preventive Services: A Bright Future Handbook. 103-111. Accessed February 27, 2021.
  14. Parental marijuana use was associated with elevated risk of substance use among adolescent and young adult offspring living in the same household. Substance Abuse and Mental Health Services Administration. November 27, 2019. Accessed February 28, 2021.
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