By Julia Milzer, University of Colorado Anschutz Medical Campus
The largest cannabis study ever investigates the effects of heavy and recent cannabis use on brain function, finding potential health risks for young people
A new study, published yesterday and the largest of its kind ever completed, examined the effects of cannabis use on over 1,000 young adults, aged 22 to 36, through brain imaging technology. Researchers found that 63 percent of heavy lifetime cannabis users exhibited reduced brain activity during a working memory task while 68 percent of recent users also demonstrated similar deficits.
Working memory is the ability to retain and use information to perform tasks. For example, working memory allows a person to follow instructions they’ve just been given or to mentally visualize and manipulate information, like solving a math problem.
‘Make informed decisions’
“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 one of the study's authors, Joshua Gowin, PhD., assistant professor of radiology at the University of Colorado School of Medicine on Anschutz Medical Campus.
The study considered young people who’ve consumed cannabis more than 1,000 times "heavy" users, 10 to 999 times "moderate" users and less than 10 times as "nonusers."
A silent video of Justin Juvera, senior professional research assistant, finishing a brain scan of a study participant. Video by University of Colorado School of Medicine.
The researchers then studied the neural response of participants during a magnetic resonance imaging session and gave them cognitive tasks to complete. The tasks tested working memory, reward, emotion, language and motor skills, such as tapping a finger to map brain control.
Significant effects on function and performance
The researchers found that cannabis had a statistically significant effect, meaning the observed impact was not caused by random chance. This effect was seen in both recent and lifetime cannabis users.
"We applied the highest standards to our research, setting rigorous thresholds ... across all tests, said Gowin.
During working memory tasks, the researchers observed that heavy cannabis use appeared to reduce activity in certain areas of the brain. These regions are involved in important cognitive functions, like decision-making, memory, attention and emotional processing.
Gowin said the research also suggested that abstaining from cannabis before doing a cognitive task could help improve performance.
“People need to be aware of their relationship with cannabis since abstaining cold turkey could disrupt their cognition as well. For example, heavy users may need to be more cautious,” Gowin said.
He added, “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.”
The University of Colorado Anschutz Medical Campus is a medical destination at the forefront of transformative science, medicine, education and patient care. This article was emailed to us for publication.
