A study of thousands of men followed for decades has found no significant harmful effects of cannabis use on age-related cognitive decline.
Given the prevalence of cannabis use, its potential association with cognitive decline has significant implications for public health. But any link to age-related cognitive decline hasn’t been thoroughly studied, and existing studies have shown mixed results. Now another study has added to that mix.
Danish researchers primarily from the University of Copenhagen set out to investigate the relationship between cannabis use and age-related cognitive decline from early adulthood to late midlife.
This involved 5,162 men who had participated in Danish follow-up studies on cognitive aging for a mean of 44 years. The results revealed men with a history of cannabis use had less cognitive decline from early adulthood to late midlife compared to those without a cannabis use history. The mean cognitive decline was found to be 6.2 IQ points and cannabis use was associated with 1.3 IQ points less cognitive decline than the reference group.
While acknowledging several limitations of the study, the authors say their results align with most existing studies, suggesting no association between cannabis use and greater cognitive decline (emphasis on greater).
“Further studies are needed to investigate whether these findings reflect that there are no adverse effects on cognitive decline or that the effects of cannabis are temporary and disappear after a prolonged period of time,” they state.
The study report has been published in the journal Brain And Behaviour.
Commenting on the study’s findings, NORML’s Deputy Director Paul Armentano lamented existing stereotypes often go unchallenged.
“These results contradict one of the more prominent and longstanding stereotypes about cannabis and cannabis consumers,” he said. “It is even more unfortunate that studies refuting these long-held stereotypes seldom receive the type of mainstream attention they deserve.”
Another recent study concluded adult medicinal cannabis patients do not experience adverse changes in either brain morphology or cognitive performance after a year of regular use.
It should be noted heavy exposure to cannabis during adolescence has been found to potentially alter cognitive function. The US Centers for Disease Control and Prevention (CDC) states:
“Cannabis use can have permanent effects on the developing brain when use begins in adolescence, especially with regular or heavy use … The teen brain is actively developing and continues to develop until around age 25.”
