Combining Cannabis, Alcohol, and Energy Drinks on the Same Day Means the Heaviest Drinking and Most Problems | Research

The takeaway

College students who used cannabis, alcohol, and energy drinks on the same day drank more and experienced more negative consequences than on days using any combination of just two substances.

College health educators, substance use prevention specialists, and young adults who combine multiple substances.

What the researchers found

Days with simultaneous alcohol + cannabis + energy drinks (SAM+AmED, 15.4% of drinking days) were associated with increased drinking quantity and more negative consequences compared to days with only SAM or only AmED. SAM-only and AmED-only days were also riskier than alcohol-only days.

Why it matters

The triple combination of cannabis, alcohol, and energy drinks is common (15% of drinking days) and represents the highest-risk pattern for college students. Identifying this specific pattern helps target prevention efforts at the most dangerous behavior.

The numbers in context

21% of drinking days were AmED days, 19% were SAM days, 15.4% were SAM+AmED days. SAM+AmED days had increased drinking and negative consequences vs both SAM-only and AmED-only days. SAM-only and SAM+AmED (but not AmED-only) days had more positive consequences than alcohol-only days.

How the study worked

30-day timeline followback interview with college students who engaged in both simultaneous alcohol-cannabis (SAM) use and alcohol mixed with energy drinks (AmED). Day-level data classified drinking days by substance combination and compared consumption and consequences.

What this study cannot tell us

Selected sample of college students who already engage in multi-substance use — not generalizable to all students. Retrospective recall over 30 days. Cannot determine causality or the order of substance use within a day. No measure of quantity for cannabis or energy drinks.

How to read the evidence

Day-level analysis with timeline followback provides detailed behavioral data, but selected sample and retrospective design limit generalizability.

When this study was published

Published 2025.

The bigger picture

Prevention programs typically address substances individually, but this study shows the combination matters. The finding that SAM days had both more negative AND positive consequences suggests students experience rewarding effects that reinforce this risky pattern.

Questions still open

Why does adding cannabis to alcohol increase positive consequences as well? Do energy drinks mask intoxication, leading to more drinking? Would targeted messaging about the triple combination reduce its occurrence?

Common questions

Why is the triple combination so risky?

Each substance affects judgment and consumption differently. Cannabis and energy drinks may both alter perception of intoxication, leading to heavier drinking. The compounding effects on cognition and risk-taking increase the likelihood of negative consequences.

Do energy drinks make the combination worse than just cannabis and alcohol?

Yes — days with all three substances showed more drinking and more negative consequences than days with cannabis+alcohol or alcohol+energy drinks alone.

Read the original research

Simultaneous use of alcohol, cannabis, and energy drinks predicts increased daily alcohol consumption and alcohol consequences.

Experimental and clinical psychopharmacology, 33(1), 8-15

View on PubMed ↗Publisher’s paper ↗

Citation

Waddell, Jack T; McDonald, Abigail E; Quiroz, Selena I; Corbin, William R. (2025). Simultaneous use of alcohol, cannabis, and energy drinks predicts increased daily alcohol consumption and alcohol consequences.. Experimental and clinical psychopharmacology, 33(1), 8-15. https://doi.org/10.1037/pha0000736