Sign in Subscribe
Youth

Marijuana Use Linked to Disrupted Brain Development in Adolescents and Young Adults

Strategic Insights

— 2 min read

Adolescents and young adults who heavily use marijuana are more likely to have disrupted brain development, according to a new study by pediatric researchers. The study found abnormalities in areas of the brain that interconnect brain regions involved in memory, attention, decision-making, language, and executive functioning skills. The researchers caution that the study is preliminary and does not demonstrate that marijuana use causes the brain abnormalities. However, the findings are of particular concern because adolescence is a crucial period for brain development and maturation.

Key Takeaways:

  • The study found abnormalities in areas of the brain that interconnect brain regions involved in memory, attention, decision-making, language, and executive functioning skills.
  • The researchers used diffusion tensor imaging (DTI) to measure water movement through brain tissues, which suggested damage or an arrest in development of the myelin sheath that surrounds brain cells.
  • Myelin provides a coating around brain cells similar to insulation covering an electrical wire, and its proper function is essential for signaling within the brain.
  • The study involved 14 young men from a residential drug treatment center and 14 age-matched healthy controls, with an average age of 19.
  • The subjects with a history of heavy marijuana use smoked nearly 6 marijuana joints daily in the final year before they stopped using the drug.
  • The study team found abnormal patterns of water diffusion among the young men with histories of marijuana use, suggesting damage to the myelin sheath.
  • The findings suggest that early-onset substance use may alter the development of white matter circuits, especially those connections among the frontal, parietal, and temporal regions of the brain.
  • Abnormal white matter development could slow information transfer in the brain and affect cognitive functions.
  • The study's limitations include a small sample size, with five of the 14 subjects with heavy cannabis use also having a history of alcohol abuse.
  • The study does not demonstrate a causal link between marijuana use and brain abnormalities, but rather an association.

Statistics:

  • The average age of the study subjects was 19.
  • The subjects with a history of heavy marijuana use smoked nearly 6 marijuana joints daily in the final year before they stopped using the drug.
  • The study involved 28 subjects, with 14 from a residential drug treatment center and 14 age-matched healthy controls.
  • 5 of the 14 subjects with heavy cannabis use also had a history of alcohol abuse.
  • The study was supported by a grant from the National Institute of Mental Health.

Sources:

  • Ashtari, M., et al. (2009). Marijuana Use as a Risk Factor for Disrupted Brain Development in Adolescence. Journal of Psychiatric Research, 43(11), 937-945.
  • The Children's Hospital of Philadelphia. (n.d.). Brain Development. Retrieved from
  • National Institute of Mental Health. (n.d.). Grant Support for Research. Retrieved from

Read more