Cannabis use reduces the chances someone will try to quit smoking, according to findings published by UW-CTRI researchers in Drug and Alcohol Dependence.
Researchers found that, among 160 Options Study participants, cannabis co-use reduced switching from cigarettes to vapes or very-low nicotine cigarettes (VLNCs).
“I was surprised that almost half of participants reported cannabis use in the last year and that more than one-third reported cannabis use within the last month,” said UW-CTRI Director of Research and lead author Dr. Megan Piper. “Given that cannabis use – medical or recreational – is illegal in Wisconsin, these numbers seemed high to me.”
Participants were given vapes, VLNCs, or no product. They sampled their assigned study product while still smoking cigarettes for a week, then were asked not to smoke regular cigarettes and only use their vapes, VLNCs or no product (the first switch week). A washout week followed, then participants had another second switch week. During one switch week participants used a nicotine patch and during the other switch week they used a placebo patch – but they didn’t know which one they had each week.
Meanwhile, participants used cannabis as they typically did throughout the study.
“I think it is going to be important to understand how cannabis use might interfere with people’s ability to quit smoking,” Piper said. “Participants in this study were equally motivated to quit smoking tobacco and had similar confidence in their ability to quit smoking tobacco, whether they used cannabis or not. However, those who used cannabis still had more trouble substituting e-cigarettes or very low nicotine cigarettes for their usual cigarettes and were less likely to actually make a quit attempt.
“These results are consistent with other research findings, suggesting that this is an important phenomenon for us to understand so we can help people who use cannabis be successful if they want to quit using tobacco.”
This research builds on UW-CTRI’s decades of work with the Wisconsin Nicotine Treatment Integration Project (WiNTiP), and a meta-analysis of 19 studies that found people are 25% more likely to quit their other drug addictions when they simultaneously address their tobacco addiction.
“Although participants who joined the study were not initially planning to quit smoking cigarettes anytime soon, many said they had actually tried to quit when we checked back three months later.” said UW-CTRI Researcher Dr. Jesse Kaye. “People who used cannabis were about half as likely to try to quit cigarettes compared to those who didn’t use cannabis (16.7% vs. 31.4%). More research is needed to understand why people who use cannabis may be less likely to try to quit smoking cigarettes.”
“It was also interesting to note that 78% of participants who used cannabis in the last 30 days were smoking it,” Piper said. “Only 5.5% reported vaping (14.5% reported using edibles). This suggests that such participants are still being exposed to harmful products of combustion on a regular basis. Also, using tobacco and cannabis in the same form may be part of what makes it more difficult to quit smoking tobacco. Definitely something for us to explore further.”
Piper ME, Kaye JT, Piasecki TM, Yang JJ, Buu A. (2025) Cannabis Use Among Adults Who Smoke Tobacco: Relations with Switching from Combusted Cigarettes to E-Cigarettes or Very Low Nicotine Cigarettes. Drug and Alcohol Dependence. Online August 5, 2025.