An fMRI study found cannabis-using youth had decreased activation in frontostriatal brain circuits during cognitive conflict resolution, including the ventromedial prefrontal cortex, striatum, and thalamus, compared to non-using peers.
Neuroscientists studying adolescent addiction, clinicians assessing youth cannabis use, and researchers developing circuit-based interventions.
Weaker self-regulation circuits
What the researchers found
Cannabis-using youth (n=28) showed decreased conflict-related activation in ventromedial prefrontal cortex, striatum, pallidum, and thalamus compared to healthy controls (n=32) during a Simon task. Frontostriatal connectivity did not differ between groups. Findings are consistent with adult cannabis studies and suggest these circuit disturbances appear early.
Why it matters
Self-regulatory control deficits are thought to both contribute to and result from addiction. This study shows frontostriatal circuit changes appear early in the course of cannabis use, not just after years of chronic use.
The numbers in context
28 cannabis-using youth, 32 controls. Decreased activation in vmPFC, striatum, pallidum, thalamus during conflict. Connectivity was similar between groups. Findings consistent with adult literature.
How the study worked
fMRI study of 28 cannabis-using youth and 32 age-matched healthy controls during a Simon conflict task. General linear modeling compared brain activation patterns. Psychophysiologic interaction analyses examined frontostriatal connectivity.
What this study cannot tell us
Cross-sectional design cannot determine causality. Cannabis use history varied. Other substance use and psychiatric comorbidities may contribute. Small sample. Cannot distinguish pre-existing traits from cannabis effects.
How to read the evidence
Rated moderate because the study is well-designed with appropriate controls and methodology, though cross-sectional design and moderate sample size are limitations.
When this study was published
Published in 2019.
The bigger picture
Frontostriatal circuits are the brain's self-regulation infrastructure. Finding deficits in youth cannabis users suggests these circuits may be both a vulnerability factor for cannabis use and a target of its effects, creating a potential feedback loop.
Questions still open
- Do frontostriatal deficits precede cannabis use or result from it? Could these circuit measures predict who will develop cannabis use disorder? Would circuit-based interventions (e.g., neurostimulation) help?
Common questions
Does cannabis affect self-control brain circuits in young people?
Read the original research
Deficient Functioning of Frontostriatal Circuits During the Resolution of Cognitive Conflict in Cannabis-Using Youth.
Journal of the American Academy of Child and Adolescent Psychiatry, 58(7), 702-711
Citation
Cyr, Marilyn; Tau, Gregory Z; Fontaine, Martine; Levin, Frances R; Marsh, Rachel. (2019). Deficient Functioning of Frontostriatal Circuits During the Resolution of Cognitive Conflict in Cannabis-Using Youth.. Journal of the American Academy of Child and Adolescent Psychiatry, 58(7), 702-711. https://doi.org/10.1016/j.jaac.2018.09.436
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