A perspective published Nov 9, 2025, in The American Journal on Drug and Alcohol Abuse critically evaluates neuroscientific claims used to support a minimum legal age (MLA) of 25 for non-medical cannabis use. The article, “Challenging the 25-Year-Old ‘Mature Brain’ Mythology: Implications for the Minimum Legal Age for Non-Medical Cannabis Use,” reviews structural, microstructural, synaptic, and gene-expression evidence on brain development and assesses its policy implications. The article was co-authored by D4DPR president Bryon Adinoff and board member Julio C. Nunes.
Although synaptic pruning, gene regulation, and prefrontal cortical refinement continue into the third decade of life, the authors find no empirically defined neurodevelopmental endpoint at age 25. Brain maturation is shown to be nonlinear, region-specific, and influenced by sex and individual physiology. Importantly, current evidence does not demonstrate significant long-term cognitive or neurophysiological harm from cannabis use in individuals aged 18–25 compared with those older than 25.
The authors conclude that an MLA of 18–21 is consistent with neurobiological evidence, existing legal thresholds for alcohol and tobacco, and societal expectations. They emphasize that policy should integrate neurobiological findings with legal, justice, sociocultural, and historical considerations, rather than relying on a misapplied and inaccurate neuroscientific narrative.
The article was featured in Marijuana Moment on November 11, 2025.
Below is a preprint of the full paper.
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