“As cannabis use continues to grow globally, studying its effects on human health has become increasingly important. By doing so, we can provide a well-rounded understanding of both the benefits and risks of cannabis use, empowering people to make informed decisions and fully comprehend the potential consequences," said first author of the study, Joshua Gowin, PhD, assistant professor of radiology at the University of Colorado School of Medicine, in a press release.
For the study, the researchers analyzed data from 1003 adults aged between 22 and 36 years old from the Human Connectome Project. Participants completed seven cognitive tasks- including tests of working memory, reward, emotion, language, and motor skills while undergoing magnetic resonance imaging. Measures of urine toxicology and cannabis use were also included in the analysis.
Individuals were identified as heavy lifetime cannabis users if they used the substance more than 1000 times, moderate users if they used the substance between 10 and 999 times, and nonusers if they used the substance less than 10 times.
Ultimately, the researchers found that 63% of heavy lifetime cannabis users and 68% of recent users demonstrated reduced brain activity and worse performance in working memory tasks. The researchers noted that no other tasks were linked to lifetime history of heavy use, recent use or dependence diagnosis.
"We applied the highest standards to our research, setting rigorous thresholds for statistical significance across all seven cognitive function tests. To minimize the risk of false positives, we employed false discovery rate (FDR) correction. While some of the other tasks indicated potential cognitive impairment, only the working memory task showed a statistically significant impact,” said Gowin
“There are a lot of questions we still need answers to regarding how cannabis impacts the brain. Large, long-term studies are needed next to understand whether cannabis use directly changes brain function, how long these effects last and the impact on different age groups,” he concluded.
Sources: EurekAlert, JAMA Network Open
