Adverse Effects of Cannabis on Adolescent Brain Development: A Longitudinal Study

Area of Science:

• Neuroscience
• Adolescent Psychology
• Addiction Research

Background:

• Cannabis use is increasing among adolescents.
• Understanding cannabis's impact on developing brains is crucial.
• Previous research lacks longitudinal data on adolescent cannabis use and brain connectivity.

Purpose of the Study:

• To investigate longitudinal changes in frontally mediated resting-state functional connectivity in adolescents with and without cannabis use disorder (CUD).
• To examine the relationship between baseline functional connectivity, subsequent cannabis use, and cognitive outcomes.
• To assess the long-term effects of adolescent cannabis exposure on intelligence and cognitive function.

Main Methods:

• Longitudinal study comparing 22 adolescents with CUD and 43 healthy controls (HCs).
• Resting-state functional connectivity MRI was used to assess frontally mediated networks.
• Cognitive function and intelligence quotient (IQ) were measured at baseline and follow-up.

Main Results:

• Healthy controls showed increased functional connectivity over time, unlike the CUD group.
• Adolescents with CUD exhibited decreased functional connectivity between caudal anterior cingulate cortex (ACC) and other frontal regions.
• Lower baseline connectivity predicted higher cannabis use, which in turn predicted lower IQ and slower cognitive function.

Conclusions:

• Adolescent cannabis use is associated with detrimental longitudinal changes in brain resting functional connectivity.
• Repeated cannabis exposure during adolescence may impair cognitive functions and intelligence.
• Findings highlight the neurodevelopmental risks associated with adolescent cannabis consumption.