Lesson “The Real Risks of Marijuana”

First published 2019. To view the latest Heads Up content, click here.

As many states legalize the recreational use of marijuana for adults, teens
may be getting the message that the drug is safe. While marijuana is the most
commonly used illicit drug among middle and high school students, the drug
poses serious health risks
to teens. By sharing the student article “The Real
Risks of Marijuana,” teaching the lesson, and engaging students with the activity
sheet, you’ll help students understand the dangers of marijuana use.


Science Literacy, English Language Arts, Health/Life Skills


RST.6-8.1 / RST.9-10.1

  • Cite specific textual evidence to support analysis of science and technical texts

  • Obtaining, Evaluating, and Communicating Information

Cross – Cutting Concept

  • Cause and Effect: Mechanism and Prediction

Core Idea

  • Structure and Function
  • 8. Science, technology, and society



  1. How does marijuana affect the brain? (The chemical compound THC alters the
    communication between neurons. This can affect coordination and reaction time, and is associated with problems with attention, memory, learning, and decision-making.)
  2. Why are teens more vulnerable to the harmful effects of marijuana? (The brain continues to develop until the mid-20s. Using drugs—including marijuana—can
    negatively impact brain development. Since the adolescent brain is still developing, these changes may be long-lasting.)
  3. Why may CBD products not have the health benefits they claim? (CBD products are not FDA-regulated, so they have not been rigorously tested by an independent agency to make sure they are safe and contain exactly what their labels claim.)


  • Grades 6–8: Use your own words to explain how marijuana use can cause changes to a person’s brain.
  • Grades 9–10: Describe at least two ways marijuana use may negatively impact a person’s life in the long term.
  • Grades 11-12: Imagine that you have a friend who is using marijuana. What would you say to them to convince them to stop?


“The Science of Marijuana: How THC Affects the Brain”

Writing prompt: Explain why using marijuana could have a negative impact on a student’s performance. Use evidence from “The Science of Marijuana: How THC Affects the Brain” and
“The Real Risks of Marijuana” to support your reasoning.

Student Activity Sheet


  1. False. Supporting evidence may include: Marijuana today contains roughly three times the concentration of THC than the drug did 30 years ago. People can end up in the emergency room with severe symptoms after taking too much THC.
  2. False. Supporting evidence may include: Teens who use marijuana recreationally are four to seven times more likely than adults to develop what is known as marijuana use disorder.
  3. False. Supporting evidence may include: Marijuana is associated with problems with attention, memory, learning, and decision-making. Using marijuana can cause people to develop marijuana use disorder. The severe types of this disorder are considered addiction. Inhaling or ingesting too much THC can result in people ending up in the emergency room.
  4. True. Supporting evidence may include: Marijuana can lead to problems with attention, memory, and learning. These effects may last for days or weeks.
  5. True. Supporting evidence may include: Marijuana (specifically, the presence of THC in the brain) can impact a person’s coordination and reaction time, making it dangerous to drive a car.
  6. False. Supporting evidence may include: Teens are more susceptible to the effects of drugs like marijuana because their brains are still developing. Drug use during the time of adolescent brain development may have long-lasting impacts on brain function. Because their brains are still developing, teens also have a higher risk of becoming addicted to marijuana.

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