Marijuana use among older adults may not have a major effect on cognitive function.

That is the takeaway of a new review published late last year in Archives of Clinical Neuropsychology. Reviewing a combination of both human and animal trials, the researchers examined the studies “to critically examine the extent of literature on this topic and highlight areas for future research” on the effect of cannabis exposure on older subjects.

“Six articles reported findings for older populations (three human and three rodent studies), highlighting the paucity of research in this area. Human studies revealed largely null results, likely due to several methodological limitations,” the researchers wrote. “Better-controlled rodent studies indicate that the relationship between [THC] and cognitive function in healthy aging depends on age and level of THC exposure. Extremely low doses of THC improved cognition in very old rodents. Somewhat higher chronic doses improved cognition in moderately aged rodents. No studies examined the effects of cannabidiol (CBD) or high-CBD cannabis on cognition.”

In conclusion, the authors wrote that their “systematic scoping review examined current research on the relationship between cannabis use and cognitive function in healthy aging and provides a starting point for future research,” as quoted by NORML.

“Ultimately, given the recent increase in cannabis use among older adults, future human research should examine the relationship between both early and later-life cannabis use on cognitive function within more homogenous, older adult samples of people who use cannabis,” they wrote.

Cannabis Use Among Seniors

A study conducted in 2018 found that marijuana use among older Americans has been on a steady rise in recent years, both in states where prohibition has been lifted and where it has not. The research found that male Americans between the ages of 60 and 64 had the highest rate of cannabis use, with nearly 13 percent reporting having used it in the last 30 days, almost a nine percent increase since 2016. 

Another study published last year produced similar findings. That study, published in JAMA Internal Medicine, found that “use of cannabis in the past year by adults 65 years and older in the United States increased sharply from 0.4% in 2006 and 2007 to 2.9% in 2015 and 2016.” 

Aside from the rise in legalization and the resulting drop in stigma, marijuana use among older adults is in some ways a logical pairing. After all, aging can bring about chronic pain that is often treated with prescription drugs. But a study last year from a group of Israeli researchers may have also provided peace of mind to such older cannabis patients. The researchers found “no significant differences in cognitive function” between the groups of chronic pain patients aged 50 and older who have medical cannabis licenses, and a separate group of those who do not have such a license.

“Considering the increasing use of [medical cannabis] in older populations, this study could be a first step towards a better risk-benefit assessment of [medical cannabis] treatment in this population,” the researchers wrote in their conclusion. “Future studies are urgently needed to further clarify the implications of late-life cannabis use for brain health.”