A recent study by researchers at the University of California San Diego School of Medicine found that people with cannabis use disorder (CUD) are more than three times more likely to develop oral cancer within five years than people without CUD.
This study shows that long-term cannabis use might come with serious health risks.
The study was published in the journal Preventive Medicine Reports.
Cannabis use disorder is a condition where someone becomes dependent on cannabis and finds it hard to stop using it. In 2022, over 17 million people used cannabis daily or nearly every day. Research suggests that about 3 out of 10 users may develop CUD.
As cannabis becomes more common and socially accepted, it’s important to understand the possible health effects. While some people think cannabis is safer than tobacco or alcohol, we still don’t know all the risks—especially when it comes to cancer.
Tobacco smoking is known to raise the risk of oral cancer. Since cannabis smoke also contains harmful chemicals, researchers wanted to see if cannabis use also increases this risk.
Dr. Raphael Cuomo from UC San Diego said that cannabis smoke has many of the same cancer-causing chemicals as tobacco smoke. These can damage the lining inside the mouth and possibly lead to cancer.
The study looked at the medical records of over 45,000 people. Among them, 949 had CUD.
The researchers found that people with CUD were more than 3 times (325%) more likely to develop oral cancer within five years. Tobacco smokers with CUD were over 6 times (624%) more likely to get oral cancer compared to smokers without CUD.
Even when the researchers adjusted for age, sex, weight, and smoking habits, the increased risk of cancer stayed. This suggests that cannabis use itself may raise cancer risk, not just smoking tobacco. One possible reason is that THC, the active ingredient in cannabis, can weaken the immune system.
This research shows that people with cannabis use disorder may need to be more aware of their oral health. Doctors and public health programs should consider talking about cancer risks when treating people with substance use issues. More research is still needed to fully understand how cannabis affects cancer risk.
If you care about cancer, please see recent studies about new way to increase the longevity of cancer survivors, and results showing new way to supercharge cancer-fighting T cells.
For more information about health, please see recent studies about how drinking milk affects risks of heart disease and cancer and results showing that vitamin D supplements could strongly reduce cancer death.
The study is published in Preventive Medicine Reports.
Copyright © 2025 Knowridge Science Report. All rights reserved.
