It all started with the release of Red Bull in 1997. Since then, the energy drink market has grown into a multibillion-dollar industry that uses aggressive and innovative marketing strategies to target teens and young adults, according to a new article published in JAMA.

Drink companies insist their products can help enhance mental or physical performance, but researchers have linked energy drinks to high heart rates and blood pressure along with insomnia and anxiety issues. When alcohol is mixed with them, the dangers are even higher.

Research shows that drinking alcohol and caffeine together can make a person less aware of how drunk they are, according to the National Institute on Alcohol Abuse and Alcoholism (NIAAA). When people don’t feel drunk, they tend to miss the signs of alcohol overdose and make poor choices.

“People feel less sleepy and less impaired, but when you look at their performance—like their ability to drive a car—they are still just as impaired by the alcohol” as without the caffeine, said Aaron White, Ph.D., health sciences administrator at NIAAA, in an institute article.

Popular Drinks Carry Risks

Alcohol mixed with energy drinks (AMED) has become increasingly popular, especially among teens and college students. A 2007 study found that almost half of the college students surveyed had tried the combo.

The trend includes cocktails served at bars such as Red Bull and vodka, premixed caffeinated alcoholic beverages, self-mixed beverages, and alcohol and energy drinks consumed separately but in the same night.

Brand names like Red Bull, AMP, and Rockstar tend to have high levels of caffeine, many added sugars, and other herbal stimulants like guarana and taurine. Researchers have found that these added ingredients are cause for concern in young adults.

One of the worst offenders was Four Loko, a premixed variety that after intense pressure from the Food and Drug Administration removed caffeine and other stimulants from its formula in 2010. The malt liquor drink was a favorite on college campuses, but was connected to several hospitalizations and deaths.

“There is an extremely strong association between drinking alcoholic energy drinks and serious injury,” said Mary Claire O’Brien, M.D., Associate Professor of Emergency Medicine at Wake Forest University School of Medicine in a statement.

Drinkers who consume alcohol mixed with energy drinks are three times more likely to binge drink (based on breath alcohol levels) than drinkers who do not report mixing alcohol with energy drinks, according to the Centers for Disease Control and Prevention. Binge drinking can result in alcohol poisoning, the symptoms of which include mental confusion, vomiting, seizures, breathing problems, and extremely low body temperatures.

“There is only a small safety window when it comes to alcohol,” said White. “You can quickly go from too much to way too much.”

In October, Healthline reported on the deaths linked to Monster Energy drinks and the continuing debate on caffeine drinks.