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Gowin JL, et al. Brain Function Outcomes of Recent and Lifetime Cannabis Use. JAMA Netw Open. 2025;8(1):e2457069. doi:10.1001/jamanetworkopen.2024.57069

https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2829657

This research sought to answer the question: ”Are recent cannabis use and lifetime cannabis use associated with differences in brain function during cognitive tasks?”

“In this cross-sectional study of 1003 young adults, heavy lifetime cannabis use was associated with lower brain activation during a working memory task; this association remained after removing individuals with recent cannabis use. Differences in demographic variables, age at first cannabis use, alcohol use, or nicotine use did not explain these results. These findings suggest that cannabis use is associated with short- and long-term brain function outcomes, especially during working memory tasks. A lifetime history of heavy cannabis use was associated with lower brain activation during a working memory task. These findings identify negative outcomes associated with heavy lifetime cannabis use and working memory in healthy young adults that may be long lasting.”

Note: Marijuana use can harm the respiratory and cardiovascular systems in ways similar to tobacco use. How marijuana use affects the brain is under increased study with investigation of how effects interact with other drug use like nicotine and alcohol use. Results of this study show that nicotine affects marijuana functioning but that different effects occur in various areas of the brain and with short and long-term use. The complexity of drug interactions and the relationship of neural networks are becoming more explicit, and this research adds to an understanding of how marijuana drugs affect brain function with and without nicotine use. Stephen Hamann

TRC Research Commentary

Friedman AS, et al. Flavored E-Cigarette Sales Restrictions and Young Adult Tobacco Use. JAMA Health Forum. 2024;5(12):e244594. doi:10.1001/jamahealthforum.2024.4594

https://jamanetwork.com/journals/jama-health-forum/fullarticle/2828404

Findings in this US study support the notion that e-cigs are replacing combustibles for young adult smokers, and flavoring restrictions decrease e-cig use more than they increase combustible cigarette use. In Maryland USA, where specific provisions allowed menthol e-cigs in open source devices used by older e-cigarette smokers, both e-cig and combustible use declined in young adults. This methodologically complex study suggests that there should be adjustments to what is allowed to show decreases for both types of cigarettes. This suggests that mixed restrictions on e-cigarettes would work. This has not been demonstrated in real-world situations where e-cigarette bans have been utilized to control young adult use. It reflects the dilemma of a complex of restrictions that are impossible to enforce.

Comment: An enforced, complete ban on e-cigarettes, as in some existing countries, is better since there is an emergence of alternative nicotine products where combustible cigarette use is declining. Alternative nicotine products are designed to maintain harmful consumer addictions and profits for nicotine sellers. Stephen Hamann