Cannabis May Actually Improve Working Memory in Aging Brains | Research

The takeaway

Chronic oral THC enhanced working memory in aged rats of both sexes while having no effect in young adults, suggesting cannabis may reverse age-related cognitive decline in specific brain functions.

Older adults using cannabis, geriatric medicine researchers, neuroscientists studying aging, and anyone interested in cannabis's cognitive effects across the lifespan.

What the researchers found

Chronic oral THC enhanced prefrontal cortex-dependent working memory in aged rats of both sexes without affecting young adults. Acute cannabis smoke showed sex-dependent effects in aged rats (enhancement in males, impairment in females). Neither exposure worsened hippocampus-dependent memory at any age.

Why it matters

Cannabis use among older adults is the fastest-growing demographic. This counterintuitive finding — that THC may help aged brains while not affecting young ones — could shift how we think about cannabis and aging.

The numbers in context

Chronic oral THC enhanced working memory in aged rats of both sexes. Acute smoke: enhanced in aged males, impaired in aged females. Minimal age differences in THC pharmacokinetics.

How the study worked

Preclinical study testing acute cannabis smoke and chronic oral THC in young adult and aged rats of both sexes, measuring prefrontal cortex-dependent working memory and hippocampus-dependent spatial memory with pharmacokinetic profiling.

What this study cannot tell us

Rat cognition tests are simplified compared to human cognitive function. THC doses and routes may not match typical human use. Enhancement was specific to working memory — other cognitive domains were unaffected.

How to read the evidence

Well-designed study with both sexes, multiple age groups, and two routes of administration — strong preclinical evidence for an age-dependent effect.

When this study was published

Recent study providing the most comprehensive look at age-dependent cannabis cognitive effects across sex and administration route.

The bigger picture

The aging brain has a different neurochemical environment than young brains — the endocannabinoid system changes with age. This study suggests cannabinoids may have fundamentally different effects across the lifespan, potentially beneficial in aging.

Questions still open

Could low-dose THC become a cognitive therapeutic for age-related decline? Why does cannabis enhance working memory in aged brains but not young ones?

Common questions

Can cannabis help older adults' memory?

This rat study found THC improved working memory in aged animals while having no effect on young ones. This is promising but needs human clinical trials before recommendations can be made.

Does cannabis affect men and women differently as they age?

Acute cannabis smoke enhanced working memory in aged male rats but impaired it in aged females. Chronic oral THC, however, enhanced memory in both sexes, suggesting the route of administration matters.

Read the original research

Effects of cannabis smoke and oral Δ9THC on cognition in young adult and aged rats.

Psychopharmacology, 242(4), 835-853

View on PubMed ↗Publisher’s paper ↗

Citation

Zequeira, Sabrina; Gazarov, Emely A; Güvenli, Alara A; Berthold, Erin C; Senetra, Alexandria S; Febo, Marcelo; Hiranita, Takato; McMahon, Lance R; Sharma, Abhisheak; McCurdy, Christopher R; Setlow, Barry; Bizon, Jennifer L. (2025). Effects of cannabis smoke and oral Δ9THC on cognition in young adult and aged rats.. Psychopharmacology, 242(4), 835-853. https://doi.org/10.1007/s00213-025-06754-6