Has Recreational Cannabis Legalization Changed Cannabis Use and Its Effects?

In 2012 Washington and Colorado took the leap and legalized recreational cannabis use. A year later, Uruguay became the first country to legalize cannabis for recreational use at a national level. Four years later, the Canadian government followed suit. Recreational Cannabis Legalization (RCL) is gaining popularity, yet opinions on RCL remain mixed, both socially and in research.

Research looking at how RCL’s impacts cannabis use and outcomes is mixed. This led researchers at York University’s Behavioural Alcohol and Cannabis Lab and McMaster University’s Peter Boris Centre for Addiction Research to review how cannabis use and outcomes have changed before and after RCL.

The researchers looked over 61 studies published between 2016 and 2022. Two thirds of these studies came from the United States, a third from Canada and just one from Uruguay. 

Many studies addressed concerns over RCL’s effects on teens. Across eight studies, there was a slight link between RCL and teens using more cannabis but the relationships were nuanced. For example, one finding was different in studies where varying cannabis products were used and five other studies showed mixed findings on the relation between RCL and teen use. Overall, research on teen use and RCL remains mixed. 

Unlike teens, RCL’s effect on young adults and the general population are relatively consistent. RCL has a consistent link with increased use amongst young adults and the general population. However, the relationship between RCL and cannabis use in the general population is mixed. Some findings have suggested that the rise in first time users increased, while others reported a general increase in frequency and quantity of use. Overall, 80% of the studies confirmed an increase in cannabis use post-RCL.

Another topic brought up in the RCL discussion was whether legalizing cannabis raised the use of other drugs? Of note, use of alcohol with cannabis had risen by around 6% in teens. This increase was even bigger in individuals who engaged in heavy drinking. For teens who mainly used cannabis, though, there was a 24% decrease in their use of alcohol. 

There have also been findings showcasing RCL’s effects on opioid use. One study compared daily opioid use in women with pelvic pain. It found that daily use of opioids decreased after RCL. Another study found a large decrease in opioid-related deaths after RCL. Overall 40% of studies show a weak link, and 60% showcase a potential link.

How about attitudes towards cannabis? One study found that 6 months after RCL in California, individuals switched from thinking of cannabis use as ‘slightly harmful’ to ‘slightly beneficial’. But overall, 55% of studies showcase small or inconsistent findings that RCL impacted attitudes towards cannabis use.

When looking at cannabis use and health outcomes, most studies found that there was an increase in cannabis-related emergency room visits in youth. However, these findings were not always seen in older groups. The research on RCL and mental health outcomes is sparse and conflicting. Some studies found no change in hospital admissions or psychotic disorders, but one study did report an increase in diagnoses of personality disorders. Overall, two thirds of the studies found no link or mixed results.

More and more countries are legalizing cannabis. Understanding the impact of such decisions is vital to making responsible policy changes. The impact of Recreational Cannabis Legalization (RCL) on cannabis use and consequences is still one of great debate and deviseness. Further research is needed to fully understand its effects. 

Interested In learning more? Check out the full article here:

New Article from BAC Lab shows that Young Adults Mix Cannabis with Alcohol when they are Stressed, Anxious, or Depressed

Many young adults mix alcohol with cannabis to combine their effects, known as co-use. Studies show that co-use is more harmful than using either alcohol or cannabis on its own. Young adults may want to combine alcohol and cannabis for many reasons. They may want to cope with stress, to be social, to conform with peers, or to enhance the benefits of the high. They may also combine alcohol with cannabis when feeling anxious or depressed. But why do young adults combine cannabis with alcohol when they feel anxious and depressed, and how does this affect co-use behaviours and negative outcomes?

To answer these questions, our research team asked 151 young adults from Ontario who co-use cannabis and alcohol to fill out surveys about how often they co-use and its negative consequences. The surveys were done daily in three 21-day periods spaced 6 months apart. Every 6 months, we also asked them why they were mixing cannabis with alcohol and if they had symptoms of stress, anxiety or depression.

We found a link between symptoms and reasons to co-use. Some young adults were more stressed, anxious, or depressed than others. Those who were also had stronger desires to co-use alcohol and cannabis. These desires include to cope with stress, to socialize, to fit in, and to enhance their high. There were also times when young adults reported increases in their stress, anxiety and depression. During these times, they also tended to combine cannabis with heavy alcohol drinking more often. This was explained by a stronger desire to co-use to feel more high and more positive drug effects. Young adults may believe that combining cannabis with more alcohol will do a better job of making them feel better. Importantly, they also experienced more negative consequences of their co-use when they were more depressed or anxious, suggesting that this is a risky behaviour that could cause problems.

Ultimately, these findings show how a person’s reasons for co-using cannabis and alcohol predict changes in their co-use behaviours. As such, young adults who are feeling depressed or stressed out and want to co-use alcohol and cannabis should think about their specific reasons for doing so. Asking yourself why you want to co-use alcohol and cannabis can give you a sense of how you will co-use them.  If you are a young adult who combines alcohol with cannabis to feel a stronger high when stressed or anxious, you are not alone. While a reason like this seems innocent enough, it can still lead to problems. Telling yourself you want to feel a stronger high can lead to drinking more heavily when using cannabis more often, leading to more negative outcomes in the long run. Thus, based on these findings, it is recommended that young adults try to find other ways to deal with anxiety and depressed mood instead of mixing alcohol with cannabis. 

Interested in learning more? Check out the full article here: https://onlinelibrary.wiley.com/doi/10.1111/acer.70147

Check out our recent interview with CTV News:

https://www.ctvnews.ca/toronto/video/2025/09/09/new-study-looks-at-alcohol-and-cannabis-use-in-young-adults/