US researchers have uncovered a potentially surprising link between recreational cannabis use and a decreased risk of cognitive decline.
The team from Upstate Medical University in Syracuse, New York analysed a substantial dataset from the CDC (Centres for Disease Control and Prevention).
Their findings revealed a striking association: compared to non-users, individuals engaging in non-medical cannabis use, primarily for recreational purposes, exhibited a remarkable 96 per cent reduced likelihood of subjective cognitive decline (SCD).
While medical and dual users also displayed decreased odds of SCD, the results were not statistically significant. Notably, the frequency and method of cannabis consumption did not show significant associations with SCD.
SCD is a critical measure as previous research indicates that individuals experiencing it face twice the risk of dementia, a condition currently lacking a cure or definitive prevention methods.
Study lead Professor Roger Wong emphasised the unexpected nature of the findings, given previous studies linking cannabis use with cognitive decline. However, he cautioned that the study had limitations and its results represent only a snapshot of one year.
He said the main takeaway is that cannabis might offer protection for cognitive health, but stressed that longitudinal studies are essential.
Wong added it was important to understand if non-medical cannabis use leads to better cognition or if individuals with better cognition are more likely to use non-medical cannabis.
Long-term research is crucial, said Wong, but that is currently hindered by cannabis remaining illegal at the federal level in the US.
The study drew data from 4,744 US adults aged 45 and older participating in the 2021 Behavioural Risk Factor Surveillance System (BRFSS). SCD was self-reported as an increase in confusion or memory loss within the past year.
The odds of SCD were examined by reason for cannabis use, frequency, and method, after adjusting for various sociodemographic, health, and substance-use factors.
The study stands out for its focus on middle-aged and older adults, as well as its comprehensive consideration of cannabis-use nuances: medical versus non-medical, frequency, and mode of consumption.
Wong said he was surprised that mode and frequency had no bearing on SCD since other studies involving younger participants found a negative connection between brain health and cannabis use, perhaps suggesting that the age of the participants plays a role in the different results.
While limited by its inability to consider state-specific cannabis regulations, the study’s strengths include the utilisation of a national dataset. It also sheds light on the different protective effects of medical versus non-medical cannabis, attributed to the varying compositions of CBD and THC in each.
Wong theorised that the protective effect against SCD observed in non-medical users could stem from improved sleep and stress relief, common reasons for recreational use. Conversely, medical cannabis, often sought for pain relief, did not demonstrate the same cognitive health benefits.
“Based on our findings, we don’t see the CBD in medical cannabis being beneficial for cognitive health,” he concluded.
