When we talk to students about substance use, we usually focus on one thing at a time—a presentation on vaping here, a chat about drinking there. But public health data tells us that students often don’t stick to just one substance. Polysubstance use – mixing two or more substances together or using them back-to-back – is a growing trend in middle and high schools. For educators, understanding how these combinations work is key to spotting warning signs and keeping our kids safe.

What the Data Shows

According to the Monitoring the Future Study, individual past 30-day use in 2025 was:¹

THC and Nicotine

With the rise of multi-use vape pens and dual habits, mixing cannabis and nicotine has become extremely common.² According to research from the National Institutes of Health (NIH), combining these two puts double the strain on a student’s cardiovascular system, spiking heart rates and impacting blood pressure. On top of the physical strain, both substances hit the developing teenage brain at the same time. Data from the NIH PATH Study shows that teens who co-use cannabis and nicotine face significantly higher rates of severe anxiety, depression, and long-term addiction compared to those who only use one or the other.

THC and Alcohol

Mixing alcohol and weed – often called “cross-fading” – is another incredibly frequent combo among teens. Physiological studies show that alcohol causes blood vessels to dilate, which speeds up how fast the body absorbs THC. This leads to a much higher concentration of THC in the bloodstream than usual, frequently triggering severe panic, dizziness, nausea, and intense disorientation (often called “greening out”).

On the flip side, THC suppresses the body’s natural urge to vomit.³ That might sound like a minor detail, but it actually disables a critical safety mechanism, massively increasing the risk of alcohol poisoning and choking.

Prescription Meds and Alcohol

Combining prescription drugs – like ADHD stimulants, anti-anxiety meds, or painkillers – with alcohol creates a dangerous situation. CDC reports⁴ show that prescription drug misuse among teens goes hand-in-hand with binge drinking.

When kids mix alcohol with depressants like opioids or sedatives, the two multiply each other’s effects, drastically slowing down heart rate and breathing to life-threatening levels. When mixed with stimulants, the medication hides the feeling of drunkenness. Students feel totally sober even when their blood alcohol level is dangerously high, leading to accidental alcohol poisoning and extreme risk-taking.

Ketamine and Alcohol

While it’s less common than the others, mixing ketamine and alcohol is a major health emergency that staff should have on their radar. SAMHSA and NIH research highlight that because ketamine is a dissociative drug and alcohol is a heavy depressant, mixing them creates a compounding sedation effect.

Students can quickly experience total loss of motor control, memory blackouts, and deep dissociation. Physically, this combo can slow breathing down to dangerously low levels, putting a student at risk of losing consciousness or suffocating.

Common Combinations: What Educators Should Know

What This Means for Us

When we understand how these substances interact, we’re better equipped to help. A student showing up to class unusually disoriented, experiencing sudden panic, or showing dramatic mood swings might be dealing with a dangerous combination rather than just a single substance. By staying informed through clear, research-backed facts, we can have far more effective conversations, spot warning signs earlier, and keep our school communities safer.