Canberra, Australia: Cannabis exposure is not associated with significant changes in brain morphology in young adults, according to a meta-analysis of neuroimaging studies published in the journal Cannabis and Cannabinoid Research.
A team of Australian researchers reviewed sixteen studies in order to assess whether cannabis exposure is associated with changes in brain volume. The review samples included 830 participants with a mean age of 22.5 years old. Of these, 386 were marijuana users (with cannabis use onset at 15-19 years) and 444 were controls.
Researchers identified no significant differences between youth cannabis users and controls in global and regional brain volumes.
“This meta-analysis of structural MRI findings specific to youth regular cannabis users suggests no volume alterations, and no effect of age and cannabis use level on group differences in volumetry,” authors concluded. “Important areas for future work include measuring and embracing the role of cannabis potency, pubertal stage, and personal (and parental) education, to identify which brain maturation stage is most vulnerable to cannabis-related brain and mental health/wellbeing. New knowledge will be necessary to provide clear recommendations for preventive interventions targeting youth at risk and update addiction theory with novel mechanistic insights into neurodevelopment.”
Full text of the study, “Brain anatomical alterations in young cannabis users: A meta-analysis of structural neuroimaging studies,” appears in Cannabis and Cannabinoid Research. Additional information is available from the NORML fact sheet, ‘Marijuana Exposure and Cognitive Performance.’