NIDA for Teens: The Science Behind Drug Abuse
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Weeding Out the Grass (Module 4)

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Marijuana is the most commonly abused illegal drug in the United States. Nearly half of all high school students have used marijuana. Many children and adolescents—and even adults—think it is a harmless drug, especially when compared to heroin, cocaine, and cigarettes.

But marijuana is hardly harmless. Today’s marijuana is 10 to 15 times stronger than it was in the 1960s. Recent research shows that this drug has a strong physical impact on the brain and body. Because young people’s brains are still developing, it is particularly important for them to understand the effects of marijuana. This module is designed to teach students about the serious effects of marijuana.

Learning Objectives

At the end of this module, students can:

  • Explain the short- and long-term effects of marijuana use and the seriousness of these effects.
  • Understand how THC, the active ingredient in marijuana, disrupts neurotransmission.
  • Explain how marijuana can adversely affect the hippocampus and other parts of the brain.


Download this entire module in PDF format at the following link: Module 4 (PDF, 640 KB).