Cannabis may affect the brain differently throughout life

Cannabis use among middle-aged and older adults has been consistently increasing, according to the study “Medical and Nonmedical Cannabis Use, Behaviors, and Attitudes Among Middle-Aged and Older U.S. Adults”, published in 2025 in the Journal of Studies on Alcohol and Drugs.

The research analyzed data from the Health and Retirement Study, one of the leading longitudinal health surveys in the United States, with a sample of 1,324 participants, stratified by age group (50–64 years; ≥65 years; 65–74 years; ≥75 years) and gender. Weighted prevalence analyses and multivariate logistic regression models adjusted for gender, race/ethnicity, household income, and employment status were used.

The results show that 18.5% of adults aged 50-64 years reported cannabis use in the past year. Among those 65 years and older, the prevalence was 5.9%, a percentage considered high compared to previous state and national surveys.

Smoking remains the primary consumption method

Despite the expansion of oils, extracts, and edibles, the study indicates that smoking continues to be the primary consumption method among middle-aged and older adults. From a public health perspective, this pattern is relevant as inhaled consumption is associated with higher respiratory and cardiovascular risks, especially in individuals with chronic diseases and concurrent medication use.

The authors also identified behaviors associated with greater potential for harm, such as frequent use and lack of clinical monitoring.

Medicinal use is increasing, but without adequate medical supervision

Among participants who reported cannabis use, approximately 25% of middle-aged adults and 20% of older adults stated using the substance for medicinal purposes, mainly for chronic pain, sleep disorders, and aging-related symptoms.

However, only about 20% of these medicinal users reported receiving prescriptions or formal recommendations from healthcare professionals, indicating that therapeutic use predominantly occurs autonomously.

Nevertheless, the study reveals high social acceptance: over 75% of respondents consider medicinal cannabis use acceptable. Older adults, however, showed greater concern about risks, a higher tendency to classify cannabis as a “gateway” to other drugs, and more support for restrictive legislation.

Cannabis and the brain: evidence in adults and older adults

Another relevant study, titled “Lifetime Cannabis Use Is Associated With Brain Volume and Cognitive Performance in Middle-Aged and Older Adults”, was published in 2025 in the American Journal of Preventive Medicine.

The research used data from the UK Biobank, which gathers health information from over 500,000 adults, and evaluated individuals aged 40 to 70 years, with an average age of 54.5 years. The aim was to examine associations between lifetime cannabis use, regional brain volume, and cognitive performance.

Greater brain volume in regions rich in CB1 receptors

The results indicate that lifetime cannabis use was associated with greater brain volume in regions with a high concentration of CB1 cannabinoid receptors, including the hippocampus, amygdala, caudate, and putamen — areas related to memory, learning, emotional regulation, and motor functions.

Furthermore, greater history of use was associated with better performance in learning, processing speed, and short-term memory.

Effects vary throughout life and between sexes

A significant finding is that individuals who reported limited use in adolescence also exhibited, in adulthood, larger brain volumes and better cognitive performance compared to non-users. The authors highlight that the effects of cannabis appear to vary depending on the life stage, with more evident risks in early neurodevelopment and potential neuroprotective effects in older ages.

The study also identified differences between men and women, possibly related to variations in the endocannabinoid system, emphasizing the importance of considering sex as a biological variable in research on cannabis and brain health.

Implications for public health and clinical practice

Collectively, the data indicate that the growth of cannabis use among mature and older adults occurs in a context of increased social acceptance, medicinal use without adequate supervision, and emerging evidence of potential positive effects on the aging brain.

The authors advocate for the expansion of specific education, prevention, and clinical guidance strategies capable of balancing potential benefits and risks, especially in aging populations.