Study Suggests Weed Harms Teen Brains More Than Alcohol

*The following is excerpted from an online article posted on Medical Daily.

With the increasing legalization of marijuana use for adults, there also comes an increased risk of teenagers giving it a try. While research is still trying to narrow down the exact effects of the drug on the brain, many have indicated a risk of impaired cognition in younger individuals.

In their new findings, researchers at the University of Montreal, Canada, suggested these negative consequences may be long-lasting and even worse than those of alcohol consumption.

The study titled “A Population-Based Analysis of the Relationship Between Substance Use and Adolescent Cognitive Development” was published in the American Journal of Psychiatry.

The research team recruited nearly 4,000 teenagers from over thirty different Canadian schools to track them for a period of four years. At the start of the study, the teens were in seventh grade i.e. around 13 years old.

On an annual basis, each participant was asked to rate if and how often they used marijuana and drank alcohol. The team gave their word the details would not be shared with parents unless there was a risk of harm. Participants were also instructed to take computer-based cognitive tests which measured their recall memory, perceptual reasoning, inhibitory control, and short-term memory.

Overall, teens who used cannabis and drank alcohol were more likely to fare poorly on all domains of the cognitive test. It was noted an increase in marijuana use, unlike alcohol consumption, showed “additional concurrent and lagged effects” on functions like memory. Cognition did not show improvement even after students reported stopping the use of cannabis.

“This study focuses on the neuropsychological effects of cannabis. We think it’s important because it is linked to how someone functions in life,” said lead author Patricia Conrad, a professor of psychiatry at Montreal.

“Cannabis causes cognitive impairment and delayed cognitive development in adolescents. Our study showed that early marijuana use has a lasting effect on cognitive ability,” she added.

Diving into lasting effects, one association Conrad found particularly concerning was between cannabis use and inhibitory control. Lower performance in this domain is believed to be a risk factor for other addictive behaviors. Conrad said this might explain why cannabis use, in some cases, has the potential to become a gateway drug for other addictions.

Source: Medical Daily

Help us reach the next generation of families

Back to Top

[reposted by] Jim Liebelt

Jim is Senior Writer, Editor and Researcher for HomeWord. Jim has 40 years of experience as a youth and family ministry specialist, having served over the years as a pastor, author, consultant, mentor, trainer, college instructor, and speaker. Jim’s HomeWord culture blog also appears on and Jim and his wife Jenny live in Quincy, MA.

  • About HomeWord

    HomeWord helps families succeed by creating Biblical resources that build strong marriages, confident parents, empowered kids and healthy leaders. Founded by Jim Burns, HomeWord seeks to advance the work of God in the world by educating, equipping, and encouraging parents and churches. Learn More »

  • Support Our Mission

    HomeWord is non-profit, donor supported ministry. If you would like to partner with HomeWord in our effort to help more parents and families you can make a donation. Your investment will allow us to expand this ministry by offering more resources to families and churches in need.

  • Contact Information

    • HomeWord
      PO Box 1600
      San Juan Capistrano, CA

    • Send us an email

    • 800-397-9725
      (M-F: 8:30am-5pm PST)