Negative consequences do not deter young adults from using alcohol and cannabis together, study finds

Young adults who experience negative consequences from using both alcohol and cannabis simultaneously are likely to have fewer drinks the next time they drink, but are more likely to use cannabis and alcohol together.

This unexpected finding from a study just published in Alcohol: Clinical and Experimental Research may suggest that young adults associate negative consequences with their drinking, not the combination of alcohol and cannabis use. The study highlights nuanced opportunities for ‘teachable moments‘ to help reduce the harmful consequences of using cannabis and alcohol together.

Prior studies have shown that simultaneous use of alcohol and cannabis puts young adults at a greater risk for harm than using either alcohol or cannabis alone. Yet, concurrent use is quite prevalent among this age group, with nearly one out of five young adults using cannabis and alcohol together.

The current study sought to analyze how any consequences that young adults may experience while using alcohol and cannabis together influence whether they use the two substances simultaneously the next time they drink. Researchers tracked consequences reported by 18- to 25-year-old drinkers across the span of 60 days.

The 89 participants reported almost 1,000 episodes of simultaneous alcohol and cannabis use. When participants used both alcohol and cannabis at one event, 75 percent of the time they used both substances at the subsequent drinking event and consumed about four alcoholic drinks.

While participants who experienced more negative consequences from simultaneous use of alcohol and cannabis at one event were more likely to use cannabis and alcohol together at the next event and also more likely to consume less alcohol, positive consequences did not independently influence simultaneous use or quantity of alcohol consumed at the next event.

But, when participants experienced both positive and negative consequences from simultaneous use, increased positive experiences dissolved any reductions in drinking if they used both substances together at the next event.

The researchers suggest that this may indicate a bias toward reframing negative consequences as positive, or that young adults are using both substances simultaneously simply because they are both available. Future research exploring the relationship between young adults’ perceptions of negative and positive consequences and their motives, expectations, and social contexts for simultaneous use of alcohol and cannabis.