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The expanding number of states legalizing marijuana for medical and/or recreational use reflects a growing acceptance of the drug in the United States as an alternative therapy for specific medical conditions as well as a perceived legitimate drug for recreational use more akin to alcohol or cigarettes than heroin or cocaine.
Reviewed by Miriam Anne Schizer, MD, MPH, FAAP
The expanding number of states legalizing marijuana for medical and/or recreational use reflects a growing acceptance of the drug in the United States as an alternative therapy for specific medical conditions as well as a perceived legitimate drug for recreational use more akin to alcohol or cigarettes than heroin or cocaine. To date, 23 states and Washington, DC, have legalized marijuana for medical use, and 4 states and Washington, DC, for recreational use. As such, marijuana is increasingly being seen as a safe drug (albeit similar to the way alcohol and cigarettes are perceived), and legitimate access to it is growing.
However, is it safe? Also, what are the ramifications of easier access? Answers to these questions remain important as more states consider legalization, and evidence mounts on the pros and cons of marijuana use, especially for medicinal use.
Of particular interest is understanding and recognizing the effect of both short-term and long-term marijuana use in young persons as marijuana use among adolescents has increased over the years. Data show that 5.4 million persons aged 12 years or older used marijuana every or nearly every day during 2012 compared with 3.1 million persons during 2006.1 In addition, a Monitoring the Future survey funded by the National Institute on Drug Abuse (NIDA) in 2013 found that among 8th, 10th, and 12th graders, 12.7%, 29.8%, and 36.4%, respectively, had used marijuana at least once in 2012, and 7%, 18%, and 22.7%, respectively, had used marijuana in the last month.2
These increased numbers run parallel to, and appear to reflect, the diminishing perception over time of the risks of marijuana use, with the survey data showing a perceived risk among 12th graders at a nearly historic low of 36%, with 21% using marijuana in the past month.2 Undoubtedly, legalization is contributing to this increased use of marijuana in adolescents as well as the diminishing perception of its harms.
Despite the changing perception of the diminishing risks of marijuana, however, data still show that this drug is anything but benign and, in young minds in particular, still poses a danger that warrants clear education on its use. As such, the American Academy of Pediatrics (AAP) recently published a policy statement3 and technical report4 in which it opposes legalization of marijuana and supports further study to better define the best ways to reduce marijuana use among adolescents.
Given the increased number of adolescents using marijuana, along with the increased perception of its safety and easier access through state legalization, it is critical that parents and adolescents receive guidance on what the evidence on marijuana use actually shows. Pediatricians play an important role in providing this guidance.
At the recent AAP National Conference and Exhibition in Washington, DC, Miriam A. Schizer, MD, MPH, staff physician in the Adolescent Substance Abuse Program, Division of Developmental Medicine, Boston Children's Hospital, and instructor of Pediatrics at Harvard Medical School, Boston, Massachusetts, spoke on what pediatricians need to know when counseling teenagers and families about marijuana.
This article provides a summary of Schizer’s presentation, highlighting the misperceptions among adolescents and their parents about marijuana, particularly in the current climate of legalization for medical and/or recreational use in many states in which marijuana may increasingly be seen as a benign substance. Schizer provides data countering that perception and details the many adverse effects of marijuana, particularly on the adolescent brain. Finally, she provides resources for pediatricians to help educate themselves and their patients on both marijuana use and treatment options for marijuana use.
Opening her talk with a description of what marijuana is, Schizer emphasized that marijuana is not a medicine.
“The debate surrounding medical marijuana has led to a great deal of confusion on the subject,” she said. “While there are potential cannabinoid compounds in marijuana that might have therapeutic potential as individual pharmaceutical products, marijuana itself is not a medication and should not be considered as such.”
Marijuana is a form of cannabis made from the hemp plant (Cannabis sativa). It is comprised of more than 400 chemicals, of which delta-9-tetrahydrocannabinol (THC) is the primary psychoactive chemical. A fat-soluble molecule, THC accumulates in adipose tissue resulting in a long elimination half-life of several days to 1 week. With the ability to cross the blood-brain barrier and the placenta, THC acts on the body’s endogenous cannabinoid receptors found in the central and peripheral nervous system.5
Marijuana is used in multiple ways and goes by a variety of names (Table 1).5 The way in which it is used is 1 variable that determines the strength and duration of marijuana’s effects. Peak effects occur around 30 minutes after inhalation and between 2 to 4 hours after ingestion, and include tachycardia (20 to 50 beats per minute above baseline), elevated blood pressure, bronchial relaxation, dry mouth and throat, and conjunctival injection. Table 2 lists the positive and negative psychological effects.
Schizer emphasized that although there is some evidence on the therapeutic efficacy of medical marijuana, such as modest evidence of its benefit in adult patients with chemotherapy-induced nausea and vomiting,6 no studies to date have included children.
She also emphasized that only 2 pharmaceutical products have received approval by the US Food and Drug Administration (FDA; Table 3). Therefore, she stressed the need for further study to explore the therapeutic potential of pharmaceutical cannabinoid products.
“Pediatricians should be aware of the growing misperception among adolescents and their parents that marijuana is a benign substance,” said Schizer, emphasizing the currently changing climate in which more people are likely to view marijuana as benign given the efforts to legalize its use.
She stressed the need for pediatricians to know about and feel comfortable with educating parents and adolescents on the significant harmful effects of marijuana particularly on the developing adolescent brain (see “Resources for pediatricians”). These include effects on cognitive decline, mental health disorders (especially psychosis), and addiction (Table 4).7 All these effects can, in turn, increase participation in risky behavior, for which adolescents already are primed.
One particular risk that Schizer highlighted was impaired driving associated with marijuana use. Data show a significant increase in fatal motor vehicle crashes in drivers who were using marijuana (marijuana-positive) in Colorado after legalization of marijuana in 2009 compared with before legalization.8 Additional data from another study that looked at trends in alcohol and other drugs detected in fatally injured drivers in the United States between 1999 and 2010 found a significant increase in nonalcohol drugs detected in these drivers. Detected nonalcohol drugs rose from 16.6% in 1999 to 28.3% in 2010, with cannabinol the most commonly detected nonalcohol drug (increase from 4.2% in 1999 to 12.2% in 2010).9 In persons aged younger than 25 years in this study, the prevalence of cannabinol among fatally injured drivers was the highest.
Another risk that Schizer highlighted was that of addiction. Data from substance abuse treatment services between 1992 and 2011 showed that marijuana steadily increased to become the primary drug of abuse among people aged 12 years. Furthermore, marijuana was involved in 88% of all substance-abuse treatment admissions in adolescents aged 12 to 17 years. Overall, Schizer said the data show that 1 in 6 teenaged users of marijuana become addicted.10
Adding more fuel to these risks is the emergence over the past decade or so of the increasing potency of THC that is linked to more adverse effects and increased emergency department (ED) visits. In 1994, THC comprised less than 4% of marijuana products and in 2008 it comprised 9%.11 This increase in potency has resulted in an increased rate of ED visits because of marijuana use, with 96.2 per 100,000 persons visiting EDs because of marijuana use in 2004 and 146.2 per 100,000 in 2011 (with the highest peak of 149.0 per 100,000 in 2010). Adverse effects included paranoia, anxiety/panic, hallucinations, hyperemesis, erratic mood swings, and aggressive behavior.
Given these adverse effects of marijuana, Schizer encouraged pediatricians to give clear and direct medical advice in support of abstinence when counseling adolescents and their parents about marijuana use. “Adolescents who have already begun to use marijuana should be advised to quit,“ she said, “and should be offered substance use treatment if necessary.”
As legalization of marijuana rapidly changes the landscape of marijuana use in the United States, ongoing research is critical to better understand the many still unanswered questions about the impact of legalization. Schizer stressed that having effective surveillance in place will be key to detecting changes in adolescent patterns of marijuana use, as well as other downstream effects such as adverse psychiatric and medical effects, motor vehicle accidents related to marijuana use, and unintentional ingestion of marijuana by younger children. “As in other fields of medicine, there is no substitute for good data,” she said.
The need for good data is underscored by lessons learned from the history of the US tobacco industry. In a commentary that looked at what can be expected from a legal marijuana industry by looking at the history of the tobacco history, Richter and Levy trace the transformation in tobacco use from the 1880s when few people consumed tobacco products (and only 1% consumed manufactured cigarettes) to the 1950s when nearly half the population used tobacco (with 80% use by cigarette smoking) to the 1970s when lung cancer became the leading cause of cancer deaths.12 This transformation was done through innovations in product development, marketing, and lobbying by the tobacco industry. Richter and Levy point out that the marijuana industry is already doing similar types of innovations, including increased potency of the product, creation of new delivery devices, marketing on the Internet, and forming an advocacy organization called the National Cannabis Industry Association.
“The history of the tobacco industry should make us cautious about allowing a marijuana industry to develop,” said Schizer.
Contrary to a growing perception of the safety of marijuana, as well as its medical efficacy, evidence still points to the many adverse health effects of this drug, particularly in young persons. These effects include cognitive impairment, mental health disorders, and addiction. Pediatricians can help adolescents and their parents better understand the risks of marijuana and advocate against its use. Further research is needed to study the effects of marijuana use as it becomes more widely used and accessible with legalization.
1. Substance Abuse and Mental Health Services Administration. Results from the 2012 National Survey on Drug Use and Health: Summary of National Findings. NSDUH Series H-46, HHS Publication No. (SMA) 13-4795. Rockville, MD: Substance Abuse and Mental Health Services Administration; 2013. Available at: http://www.samhsa.gov/data/NSDUH/2012SummNatFindDetTables/NationalFindings/NSDUHresults2012.htm#ch2.13. Accessed January 21, 2016.
2. American College of Pediatricians. Marijuana use: Detrimental to youth. Available at: http://www.acpeds.org/marijuana-use-detrimental-to-youth. Published January 2007. Revised September 22015. Accessed January 21, 2016.
3. Committee on Substance Abuse, Committee on Adolescence. The impact of marijuana policies on youth: clinical, research, and legal update. Pediatrics. 2015;135(3):584-587.
4. Ammerman S, Ryan S, Adelman WP; Committee on Substance Abuse, the Committee on Adolescence. The impact of marijuana policies on youth: clinical, research, and legal update. Pediatrics. 2015;135(3):e769-e785.
5. National Institute on Drug Abuse; National Institutes of Health; US Department of Health and Human Services. DrugFacts: Marijuana. Available at:
Updated September 2015. Accessed January 21, 2016.
6. Borgelt LM, Franson KL, Nussbaum AM, Wang GS. The pharmacologic and clinical effects of medical cannabis. Pharmacotherapy. 2013;33(2):195-209.
7. Volkow ND, Baler RD, Compton WM, Weiss SR. Adverse health effects of marijuana use. N Engl J Med. 2014;370(23):2219-2227.
8. Salomonsen-Sautel S, Min SJ, Sakai JT, Thurstone C, Hopfer C. Trends in fatal motor vehicle crashes before and after marijuana commercialization in Colorado. Drug Alcohol Depend. 2014;140:137-144. Erratum in: Drug Alcohol Depend. 2014;142:360.
9. Brady JE, Li G. Trends in alcohol and other drugs detected in fatally injured drivers in the United States, 1999-2010. Am J Epidemiol. 2014;179(6):692-699.
10. Substance Abuse and Mental Health Services Administration, Center for Behavioral Health Statistics and Quality. Treatment Episode Data Set (TEDS): 2001-2011. National Admissions to Substance Abuse Treatment Services. BHSIS Series S-65, HHS Publication No. (SMA) 13-4772. Rockville, MD: Substance Abuse and Mental Health Services Administration; 2013. Available at: http://archive.samhsa.gov/data/2k13/TEDS2011/TEDS2011N.pdf. Accessed January 21, 2016.
11. Malone DT, Hill MN, Rubino T. Adolescent cannabis use and psychosis: epidemiology and neurodevelopmental models. Br J Pharmacol. 2010;160(3):511-522.
12. Richter KP, Levy S. Big marijuana-lessons from big tobacco. N Engl J Med. 2014;371(5):399-401
Ms Nierengarten, a medical writer in Minneapolis, Minnesota, has over 25 years of medical writing experience, authoring articles for a number of online and print publications, including various Lancet supplements, and Medscape. Dr Schizer is instructor in Pediatrics at Harvard Medical School, Cambridge, Massachusetts, and principle of the adolescent substance abuse program at Boston Children’s Hospital. The author and the reviewer have nothing to disclose in regard to affiliations with or financial interests in any organizations that may have an interest in any part of this article.