Cannabis Effects on Cognition Depend Heavily on Age: Harmful for Young Brains, Possibly Helpful in Old Age | Research

The takeaway

A scoping review of animal studies found cannabinoid exposure during brain development (prenatal and adolescent periods) was associated with lasting cognitive harm, while exposure in older animals showed potential cognitive benefits.

People interested in how age affects cannabis risks and benefits for cognition

Age determines harm vs benefit

What the researchers found

Prenatal and adolescent cannabinoid exposure consistently led to long-term cognitive deficits in animal models, while exposure in aged animals showed potential beneficial effects on cognition. The role of dosage was difficult to establish clearly, especially during adolescence, though emerging evidence suggests dose may matter more at other life stages.

Why it matters

Different age groups are using cannabis at increasing rates, from pregnant women to elderly patients seeking medical cannabis. Understanding that the same substance may be harmful during development but potentially beneficial in old age has major implications for policy and clinical guidance.

The numbers in context

Review covered 2015-2021 literature; three exposure windows examined (prenatal, adolescent, aged); consistent cognitive harm found during development; potential cognitive benefit found in aged animals; dose effects unclear for adolescent exposure

How the study worked

Systematic scoping review of PubMed from 2015 to December 2021. Included studies examining effects of natural or synthetic cannabinoids on cognitive performance in animal models where exposure occurred prenatally, during adolescence, or in older animals.

What this study cannot tell us

Animal studies have limited translatability to humans. The review focused on cannabinoid exposure broadly, including synthetic cannabinoids that differ from what humans typically use. Publication bias may favor significant findings. Dose-response relationships remain poorly characterized.

How to read the evidence

Systematic scoping review of animal literature with consistent findings across studies, but animal-to-human translation limited

When this study was published

2022 study

The bigger picture

This age-dependent pattern aligns with what we know about the endocannabinoid system's role in brain development versus maintenance. During development, cannabis may disrupt critical neural processes, while in aging brains, it may compensate for declining endocannabinoid function.

Questions still open

At what age does the transition from harmful to potentially beneficial effects occur? Would low-dose cannabis exposure in adolescence still cause cognitive harm? Could targeted cannabinoid therapies improve cognition in elderly patients with dementia?

Common questions

Is cannabis worse for young brains than old brains?

In animal studies, yes. Cannabinoid exposure during brain development (prenatal and adolescent periods) consistently caused lasting cognitive problems, while exposure in aged animals sometimes improved cognitive function.

Does the amount of cannabis matter for cognitive effects?

This review found it was difficult to establish a clear dose-response relationship, especially for adolescent exposure. The age of exposure appeared to be a more important factor than dose in determining long-term cognitive outcomes.

Read the original research

Dos(e)Age: Role of Dose and Age in the Long-Term Effect of Cannabinoids on Cognition.

Molecules (Basel, Switzerland), 27(4)

View on PubMed ↗Publisher’s paper ↗

Citation

Zamberletti, Erica; Rubino, Tiziana. (2022). Dos(e)Age: Role of Dose and Age in the Long-Term Effect of Cannabinoids on Cognition.. Molecules (Basel, Switzerland), 27(4). https://doi.org/10.3390/molecules27041411