Demographic data shows rising cannabis use among older people, so what is the likely effect on cognitive function and brain health in this group? Animal research doesn't seem to bode well, with one study finding that rats exposed to THC for 30 percent of their lifespan suffer a level of brain cell loss at 12 months of age that equals that of unexposed animals twice their age.
Encouragingly though, a new human study seems to show no cause for alarm—in this case, those consuming cannabis for chronic pain showed no differences in cognitive performance as compared to non-users of cannabis, also with chronic pain.
Published in the journal Drug & Alcohol Review, the study assessed the cognitive capabilities of 63 long-term medical cannabis consumers versus 62 non-using controls. (Medical cannabis is available on prescription in Israel, but the patient must hold a license allowing them to receive it.)
Participants, averaging 61 years, were set a battery of cognitive tests by the investigators , who assessed participants’ memory recall, reaction time, and ability to learn new information, among other parameters.
Their results found no significant differences in cognitive performance between those using medicinal cannabis and those not using it. In addition, the researchers found “no significant associations of various aspects of medicinal cannabis use patterns, including [tetrahydrocannibinol/cannabidiol] concentration, frequency and length of use, dosage and length of abstinence with cognitive performance were detected.”
Moreover, the researchers added, both groups of patients with chronic pain—those who used cannabis and those who did not—performed similarly to a standardized population with no chronic pain.
The results have been published the same month as another study that also appears to show no harm of cannabis to brain health. Published in the Canadian Geriatrics Journal this review concluded, “low-dose, short-term medical cannabis does not carry significant risk of serious mental health and cognitive adverse effects in older adults without prior psychiatric history.”