A new federally funded study published by the American Medical Association (AMA) suggests that long-standing stereotypes about cannabis negatively impacting cognitive functions like memory and control may not hold up under scientific scrutiny. Contrary to the belief that cannabis impairs brain health, this research reveals that cognitive processes such as working memory, reward, and inhibitory control are not significantly affected by medical cannabis use over the course of a year.
This study, funded by the National Institute on Drug Abuse (NIDA), offers a fresh perspective on the cognitive effects of medical cannabis use, particularly for those consuming it for conditions like pain, anxiety, depression, or sleep disorders. The findings, published in JAMA Network Open, indicate that light to moderate use of cannabis for medical reasons has minimal long-term impact on brain function.
The Study's Parameters and Findings
The study involved 57 newly certified medical cannabis patients from the Boston area. Researchers used functional magnetic resonance imaging (fMRI) to observe participants’ brain activity during tasks that required working memory, reward processing, and inhibitory control. These tasks were repeated after a year of consistent medical cannabis use to assess any changes in brain activity.
According to the study, “Working memory, reward, and inhibitory control tasks did not differ statistically from baseline to one year and were not associated with changes in cannabis use frequency.” In other words, cannabis use, in this context, did not lead to measurable cognitive decline over the year.
Researchers found "no statistically significant difference in brain activation between the two time points (baseline and one year) in those with medical cannabis cards and no associations between changes in cannabis use frequency and brain activation after one year."
These findings challenge the notion that regular cannabis use harms cognitive abilities. Instead, the study concluded that adults using medical cannabis for various symptoms experienced few significant long-term neural changes in these areas of cognition.
Cannabis Use and Cognitive Function: No Major Changes
The research offers reassurance to those who rely on medical cannabis to manage their health conditions. Many patients are concerned about potential long-term effects on brain health, given the stigma surrounding cannabis. However, this study adds to a growing body of evidence that suggests light to moderate use of cannabis does not significantly impair cognitive function.
As the study's authors from Harvard Medical School, MIT’s McGovern Institute for Brain Research, and the University of Pennsylvania School of Engineering and Applied Science stated, “Marijuana use did not have a significant association with brain activation or cognitive performance.”
The study’s findings are especially significant because they come from a year-long observation, providing a more comprehensive look at cannabis' effects on the brain over time, rather than relying on short-term assessments.
Previous Studies and the Broader Picture
This new research aligns with other recent studies that have suggested the cognitive impacts of medical cannabis may be less severe than previously thought. For example, a study from earlier this year found that prescribed medical cannabis has minimal acute effects on cognitive function in patients with chronic health conditions. That research concluded, “The absence of evidence for cognitive impairment following medical cannabis self-administration was surprising,” as recreational cannabis has been shown to impair cognitive functions in other contexts.
Furthermore, a study published last year that reviewed dispensary data revealed that cancer patients using medical cannabis actually reported clearer thinking while managing their pain. This stands in contrast to the fear that cannabis use could cloud the mind or interfere with decision-making.
Even studies involving younger populations have shown results contrary to what some might expect. A study involving teens and young adults at risk of developing psychotic disorders found that regular cannabis use over a two-year period did not trigger early onset of psychosis symptoms. In fact, some participants showed modest improvements in cognitive functioning and reported reduced use of other medications.
Long-Term Studies and Future Research
While the results of these studies are promising, they are far from the last word on the subject. The study authors themselves acknowledge that more research is needed, particularly studies that examine the effects of higher doses of cannabis, more frequent use, and usage in younger age groups. Larger, more diverse cohorts could also offer more robust insights into the long-term impacts of medical cannabis use.
“The results warrant further studies that probe the association of cannabis at higher doses, with greater frequency, in younger age groups, and with larger, more diverse cohorts,” the research team recommended.
These additional studies could help clarify whether the findings apply universally or if there are subgroups of the population that might be more vulnerable to cognitive changes related to cannabis use.
Challenging Long-Held Misconceptions
This new research also challenges older claims, such as the one made by former President Donald Trump, who once stated that cannabis use makes people “lose IQ points.” In fact, studies have shown that while cannabis users may show declines in verbal ability or general knowledge, these deficits are likely due to shared familial factors, such as genetics or upbringing, rather than cannabis use itself. The National Institute of Drug Abuse (NIDA) has even pointed out that two longitudinal studies “did not support a causal relationship between marijuana use and IQ loss.”
A New Understanding of Cannabis and Cognitive Health
This federally funded study adds to a growing body of research suggesting that the long-term cognitive effects of cannabis use, particularly in medical contexts, may be less severe than previously thought. For many medical cannabis patients, this is reassuring news. While the debate around cannabis and brain health is far from over, these findings offer a more nuanced view that challenges stereotypes and opens the door to further exploration.
As more research unfolds, it is becoming clearer that medical cannabis use, especially in moderate doses, does not pose the significant cognitive risks once feared. While further studies are necessary to examine higher doses, diverse populations, and younger age groups, the existing evidence provides hope for those seeking relief through cannabis without compromising their brain health.
