Does Cannabis Use Shrink the Brain During Aging?

Research from the University of Colorado Anschutz Medical Campus indicates that cannabis use in middle-aged and older adults is associated with larger brain volumes and improved cognitive performance.

The findings, detailed in a study by Anika Guha, Zening Fu, Vince Calhoun, and Kent E. Hutchison, challenge previous assumptions that cannabis use leads to a reduction in brain volume. According to a February 3, 2026, report from the CU Anschutz newsroom, the research found that cannabis usage in these age groups was linked to better cognition and larger brain volumes.

The study was published in the Journal of Studies on Alcohol and Drugs and became available in PubMed Central on February 11, 2026.

Functional Connectivity and Age-Dependent Effects

Other research suggests that the effects of cannabinoids on the brain may vary based on the age of the user. A study published on February 10, 2022, in Frontiers in Aging Neuroscience examined resting state functional connectivity (rsFC) in older adults.

Researchers Karli K. Watson, Angela D. Bryan, Rachel E. Thayer, Jarrod M. Ellingson, Carillon J. Skrzynski, and Kent E. Hutchison found that older adult cannabis users exhibited stronger connectivity between targets in the anterior lobes of the cerebellum and sources in the parahippocampal cortex and hippocampus compared to non-users.

The 2022 study noted that pre-clinical models indicate cannabinoids affect cognition in an age-dependent manner, showing generally beneficial effects on older animals and deleterious effects on younger ones.

Context of Cannabis Use in Aging Populations

The need to understand these interactions has increased as cannabis use among adults aged 65 and older has risen sharply over the last decade. This trend is attributed to changes in legislation, the aging Baby Boomer generation, and an increased recognition of the therapeutic potential of cannabis.

Historically, empirical evidence regarding the impact of cannabis on the aging brain has been limited. A review published on September 30, 2019, and made available in PubMed Central on June 4, 2021, found that existing studies were few and inconsistent.

That earlier review noted that long-term cannabis use might have cumulative effects on multimodal brain systems that are similarly affected during the natural aging process.

While recent evidence from the University of Colorado suggests a positive association with brain volume and cognitive function in older adults, the scientific community has previously struggled with inconsistent data regarding how cannabis specifically interacts with the aging brain.