United States: A 44-year study with over 5,000 men found that cannabis users really showed less cognitive decline as they aged as compared to non-users. The study suggests that long-term cannabis use may not harm brain function and could even help, but more research is also needed to confirm this. The age when people actually start using cannabis and how often they use it didn’t seem to affect their brain health.

A Danish longitudinal sample consisting of more than 5 000 men followed for 44 years showed that cannabis users showed deficits equal to a reduction of 6.93 IQ points from childhood to adulthood but less decline than nonusers from early adulthood to ‘‘late midlife.’’

As reported by the neurosciencenews.com, that may be because while cannabis is currently categorized as a Schedule I substance blamed for harm, today’s studies indicate it could potentially have different impacts on brains that are aging.

This study analyzed cognitive changes by comparing intelligence test results of the participants at young ages, and in later years, after four decades.

They found that users of cannabis have a narrow lead in terms of Genes’ index scores, and an increased ability to sustain IQ levels into adulthood, regardless of the lifestyle factors, including education and drug taking.

Further, we failed to observe an association between cannabis initiation age and cognitive decline, or accelerated decline associated with frequent use of cannabis.

Overall, these implications of task performance contrast prior predictions concerning escalated use of cannabis bringing about steeper cognitive deterioration.

Rather, they suggest that HCN may be due, in part, to factors such as baseline intelligence, attained education, and lifestyle more generally.

Nevertheless, even if the identified differences are quite small and can be deliberated to have little clinical relevance, the study provides a starting point for investigating other long-term effects of cannabis on cognition.

Funding: The following works were supported by several grants. The DanACo cohort was generated consolidating the two follow-up studies, namely the LiKO-15 and DiaKO-19 studies.

Phenotypes in Alcohol Use Disorders project was funded by Innovation Fund Denmark, Health and Clinical Research (Grant number 603-00520B), and further by the Center for Healthy Aging, University of Copenhagen as well as PhD scholarship grant to MG from the Faculty of Health and Medical Sciences, University of Copenhagen.

Cannabis is far more commonly used and abused substance in relation to other substances which is listed under DEA’s Schedule I, substances that has high potential for abuse.