Combined alcohol and cannabis use linked to adverse consequences in young adults, York U led study finds

TORONTO, Sept. 9, 2025 – A new longitudinal study led by York University’s Department of Psychology published today finds that young adults experiencing periods of high stress, anxiety and depressed mood more frequently combined binge drinking with cannabis use in order to get more high and drunk, and were also likely to report more adverse life consequences when combining these substances. Lead author Jeffrey Wardell, Associate Professor in York University’s Faculty of Health, says that since cannabis use among young adults has increased after Canada legalized the drug, understanding why people combine the drug and outcomes when they do is important.  

“Studies suggest that human brains are still developing into their 20s and alcohol and cannabis dependencies are more prevalent in this age group than any other,”  says Wardell, also director of the Behavioural Alcohol and Cannabis Research Lab (BAC Lab) at York. “While occasional combined use may not be a cause for concern, the study clearly shows increased risk when combining these substances. Understanding combined use can help young adults mitigate the risk, understand when they might have an issue and seek support to develop healthier coping mechanisms.” 

For the paper, published in the journal Alcohol: Clinical and Experimental Research and funded by the Canadian Institutes of Health Research (CIHR), Wardell and his research team recruited 151 young adults, ages 19 - 25, in Ontario who already used cannabis and alcohol. The participants were asked to complete daily surveys on their cannabis and alcohol use and any negative consequences they experienced as a result on their phones for three 21-day periods spaced 6 months apart. Participants also filled out surveys about their stress, anxiety and depression symptoms, as well as their motives for co-using alcohol and cannabis. 

The results showed a clear link between mental health symptoms and motivation to combine alcohol and cannabis use. 

“When they were feeling depressed or anxious, the participants were motivated to double things up because the thought was that it would make them feel better,” says Wardell. “They also reported that they were combining cannabis with binge drinking more frequently during these times.”

Wardell says that while studies show that over the short term, using substances can give people temporary relief from feelings they are seeking to escape, they can often lead to more adverse outcomes over the long term, both in terms of mental health and negative life consequences. 

Other coping mechanisms that can be more helpful include breathing exercises, meditation, physical activity, talking to a friend and seeking out help from a peer-support hotline or medical professional. Wardell says there are a number of questionnaires young adults can access online that can help them determine if their use of a substance might be problematic, with one big clue being a reliance on substances to cope with stress and unwanted feelings. 

While young adults are the most likely age group to develop an alcohol or cannabis use disorder, Wardell says it is also the age where early interventions can be helpful. 

“While they are not immune to effects on the developing brain, they're also at a stage where most of the time these behaviors are just getting started, or the patterns are just getting laid. It's a good time to give people feedback, give them advice, give them the information so they can make changes before their substance use habits become too ingrained.”  

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York University is a modern, multi-campus, urban university located in Toronto, Ontario. Backed by a diverse group of students, faculty, staff, alumni and partners, we bring a uniquely global perspective to help solve societal challenges, drive positive change, and prepare our students for success. York's fully bilingual Glendon Campus is home to Southern Ontario's Centre of Excellence for French Language and Bilingual Postsecondary Education. York’s campuses in Costa Rica and India offer students exceptional transnational learning opportunities and innovative programs. Together, we can make things right for our communities, our planet, and our future. 

Media Contact: Emina Gamulin, York University Media Relations, 437-217-6362, egamulin@yorku.ca