A massive new study sheds light on how cannabis affects the brain, particularly during cognitive tasks.
Researchers analyzed over 1,000 young adults and found that both heavy lifetime use and recent cannabis consumption significantly reduced brain activity during working memory tasks. This impairment was linked to worse performance on tasks requiring focus, problem-solving, and instruction-following. Brain imaging revealed that key regions responsible for decision-making and attention were affected.
Cannabis Use and Brain Function: A Groundbreaking Study
A new study published in JAMA Network Open examines how both recent and long-term cannabis use affects brain function during cognitive tasks.
As the largest study of its kind, researchers analyzed over 1,000 young adults aged 22 to 36 using brain imaging technology. They found that 63% of heavy lifetime cannabis users showed reduced brain activity during a working memory task, with a similar impact seen in 68% of recent users.
Reduced Brain Activity and Working Memory Impairment
This decrease in brain activity was linked to poorer performance on working memory — a crucial function that helps people retain and use information for tasks. For instance, working memory enables someone to follow instructions, mentally visualize concepts, or solve problems like math equations.
“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 the study’s first author Joshua Gowin, PhD, assistant professor of radiology at the University of Colorado School of Medicine on the University of Colorado Anschutz Medical Campus.
In the study, heavy users are considered young adults who’ve used cannabis more than 1000 times over their lifetime. Whereas, using 10 to 999 times was considered a moderate user, and less than 10 times was considered a nonuser.
MRI Scans Reveal Cannabis’ Impact on Brain Function
The researchers studied the neural response of participants during a magnetic resonance imaging (MRI) session and gave them seven cognitive tasks to complete. The tasks tested working memory, reward, emotion, language, motor skills – such as tapping a finger to map brain control, relational assessment and theory of mind.
The researchers found that cannabis had a statistically significant effect on brain function during working memory tasks, meaning the observed impact is very unlikely to be due to random chance. This effect was seen in both recent and lifetime cannabis users. The impact was less significant for the other tasks.
“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,” adds Gowin.
Key Brain Regions Affected by Heavy Cannabis Use
During working memory tasks, the researchers found heavy cannabis use appeared to reduce brain activity in certain areas of the brain (dorsolateral prefrontal cortex, dorsomedial prefrontal cortex, and anterior insula). These regions of the brain are involved in important cognitive functions such as decision-making, memory, attention, and emotional processing.
However, Gowin mentions their research also suggests that abstaining from using cannabis before doing a cognitive task could help to 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 says.
Unanswered Questions: The Future of Cannabis Research
He adds, “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.”
Reference: “Brain Function Outcomes of Recent and Lifetime Cannabis Use” by Joshua L. Gowin, Jarrod M. Ellingson, Hollis C. Karoly, Peter Manza, J. Megan Ross, Matthew E. Sloan, Jody L. Tanabe and Nora D. Volkow, 28 January 2025, JAMA Network Open.
DOI: 10.1001/jamanetworkopen.2024.57069

News
Superbugs Are Losing to Science, Light, and a Little Spice
Texas A&M researchers have found that curcumin, when activated by light, can weaken antibiotic-resistant bacteria, restoring the effectiveness of conventional antibiotics. Curcumin: A Surprising Ally Against Superbugs In 2017, a woman admitted to a [...]
New Research Shatters the Perfect Pitch Myth
For decades, people believed absolute pitch was an exclusive ability granted only to those with the right genetics or early music training. But new research from the University of Surrey proves otherwise. It’s been [...]
Why Some Drinkers Suffer Devastating Liver Damage While Others Don’t
A study from Keck Medicine of USC found that heavy drinkers with diabetes, high blood pressure, or a large waistline are up to 2.4 times more likely to develop advanced liver disease. These conditions may amplify [...]
“Good” Cholesterol Could Be Bad for Your Eyes – New Study Raises Concerns
‘Good’ cholesterol may be linked to an increased risk of glaucoma in individuals over 55, while, paradoxically, ‘bad’ cholesterol may be associated with a lower risk. These findings challenge conventional beliefs about factors that [...]
Reawakening Dormant Nerve Cells: Groundbreaking Neurotechnology Restores Motor Function
A new electrical stimulation therapy for spinal muscle atrophy (SMA) has shown promise in reactivating motor neurons and improving movement. In a pilot clinical trial, three patients who received spinal cord stimulation for one [...]
AI’s Energy Crisis Solved? A Revolutionary Magnetic Chip Could Change Everything
AI is evolving at an incredible pace, but its growing energy demands pose a major challenge. Enter spintronic devices—new technology that mimics the brain’s efficiency by integrating memory and processing. Scientists in Japan have [...]
Nanotechnology for oil spill response and cleanup in coastal regions
(Nanowerk News) Cleaning up after a major oil spill is a long, expensive process, and the damage to a coastal region’s ecosystem can be significant. This is especially true for the world’s Arctic region, [...]
The Role of Nanotechnology in Space Exploration
Nanotechnology, which involves working with materials at the atomic or molecular level, is becoming increasingly important in space exploration. By improving strength, thermal stability, electrical conductivity, and radiation resistance, nanotechnology is helping create lighter, more [...]
New Study Challenges Beliefs About CBD in Pregnancy, Reveals Unexpected Risks
CBD is gaining popularity as a remedy for pregnancy symptoms like nausea and anxiety, but new research suggests it may not be as safe as many believe. A study from McMaster University found that [...]
Does COVID increase the risk of Alzheimer’s disease?
Scientists discover that even mild COVID-19 can alter brain proteins linked to Alzheimer’s disease, potentially increasing dementia risk—raising urgent public health concerns. A recent study published in the journal Nature Medicine investigated whether both mild and [...]
New MRI Study Reveals How Cannabis Alters Brain Activity and Weakens Memory
A massive new study sheds light on how cannabis affects the brain, particularly during cognitive tasks. Researchers analyzed over 1,000 young adults and found that both heavy lifetime use and recent cannabis consumption significantly reduced brain [...]
How to Assess Nanotoxicity: Key Methods and Protocols
With their high surface area and enhanced physicochemical properties, nanomaterials play a critical role in drug delivery, consumer products, and environmental technologies. However, their nanoscale dimensions enable interactions with cellular components in complex and [...]
Nanotech drug delivery shows lasting benefits, reducing need for repeat surgeries
A nanotechnology-based drug delivery system developed at UVA Health to save patients from repeated surgeries has proved to have unexpectedly long-lasting benefits in lab tests – a promising sign for its potential to help human patients. [...]
Scientists Just Found DNA’s Building Blocks in Asteroid Bennu – Could This Explain Life’s Origins?
Japanese scientists detected all five nucleobases — building blocks of DNA and RNA — in samples returned from asteroid Bennu by NASA’s OSIRIS-REx mission. NASA’s OSIRIS-REx mission brought back 121.6 grams of asteroid Bennu, unveiling nitrogen-rich organic matter, including DNA’s essential [...]
AI-Designed Proteins – Unlike Any Found in Nature – Revolutionize Snakebite Treatment
Scientists have pioneered a groundbreaking method to combat snake venom using newly designed proteins, offering hope for more effective, accessible, and affordable antivenom solutions. By utilizing advanced computational techniques and deep learning, this innovative [...]
New nanosystem offers hope for improved diagnosis and treatment of tongue cancer
A pioneering study has unveiled the Au-HN-1 nanosystem, a cutting-edge approach that promises to transform the diagnosis and treatment of tongue squamous cell carcinoma (TSCC). By harnessing gold nanoparticles coupled with the HN-1 peptide, [...]