Brain reward responses in young people with cannabis use disorder with Martine Skumlien and Valentina LorenzettiBrain reward responses in young people with cannabis use disorder with Martine Skumlien and Valentina Lorenzetti
Addiction Audio
Dr Martine Skumlien and Professor Valentina Lorenzetti discuss their FMRI study on brain reward function in young people with cannabis use disorder and what their largely unexpected findings might suggest. The conversation also touches on brain plasticity, cognitive effects and the ongoing debate about describing addiction as a brain disease.
23:36•25 Sept 2026
Cannabis, Young Brains and Reward: What Martine Skumlien and Valentina Lorenzetti Found
Episode Overview
- The study compared young people with cannabis use disorder directly with controls, rather than just heavy cannabis users, making it a rare large-scale investigation of this specific group.
- Contrary to some addiction theories, there were no clear differences in core reward regions between those with cannabis use disorder and controls using the monetary incentive delay task.
- A difference was found in the superior medial frontal cortex during reward anticipation, but its meaning remains unclear and did not strongly relate to symptom levels.
- Current evidence on cannabis and cognition suggests effects that are often mild, variable between people and potentially reversible after a period of abstinence.
- Framing addiction as brain-based does not have to imply permanence; the conversation highlights that while substances can alter the brain, plasticity allows for change and recovery.
“"Substances can change our brains, but we can also change our brain as well."”
Understand the complexities of addiction with insights from researchers Martine Skumlien and Valentina Lorenzetti as they talk cannabis and the brain. Aimed at researchers, clinicians, students and anyone curious about how substances affect young people, this conversation stays grounded in data while keeping the tone relaxed and accessible.
Host Dr Tsen Vei Lim chats with Martine and Valentina about their study on brain reward function in young people with cannabis use disorder, using functional MRI and a well-known task called the monetary incentive delay task. You’ll hear how long‑standing theories suggest that addiction dampens the brain’s response to everyday rewards while cranking up reactions to drug-related cues.
As Martine explains, their work is "the first large scale study to compare people with cannabis use disorder … with people who don’t have" it, rather than just heavy users. The surprise? In key reward regions, they didn’t see the differences many expected. They did spot a small change in the superior medial frontal cortex during reward anticipation, but as Martine admits, "we don’t really know what it means" yet.
Valentina brings in context from animal studies, other drugs like alcohol and opioids, and what current evidence actually shows about cognition, memory and brain structure in cannabis users. You’ll also hear a careful discussion on the hot topic of whether addiction should be framed as a brain disease. Valentina stresses that brain changes are real, but so is brain plasticity: substances can alter the brain, and stopping can shift it back.
Rather than preaching, they focus on giving people information so they can make better choices and reduce harm. If you’re interested in science-based takes on cannabis, brain health and how evidence can shape treatment and policy debates, this conversation might give you plenty to think about next time you hear bold claims about weed and the brain. What kind of evidence do you feel you need to make your own decisions about substance use?
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