The appeal of caffeine is no mystery. In moderate doses, it wakes us up, elevates our mood, and speeds up our thinking. But in very high doses we feel wired, get tachycardic, and can’t sleep.

Kids are not immune to either the positives or the negatives of caffeine intake. As the energy drink industry has exploded, we are learning more about the effects of caffeine and other legal stimulants on kids, and the information is enough to make any child psychiatrist positively jittery.

Caffeine is one of the most widely available psychotropics in the world and roughly 73% of kids consume it on any given day. Historically, sodas have been the primary source, but in the last decade, this has shifted—soda consumption decreased from 62% to 38%, coffee increased from 10% to 24%, and energy drinks steadily took off, with about 35% of teens regularly partaking (Branum AM et al, Pediatrics 2014;133(3):386–393; Blankson KL et al, Pediatr Rev 2013;34(2):55–62).

Energy drinks first came on the scene in the late 1960s in Europe and Asia. Red Bull, the brand that basically created the industry, was introduced in the US in 1997, and by 2012 energy drinks were a $12.5 billion per year industry in the US (projected to be $21 billion in 2017). There are hundreds of different options available on the market and young people are now the primary target for advertising. What’s the draw and what should we know about it?

Anatomy of an Energy Drink

Most energy drinks have the same basic ingredients: guarana, taurine, ginseng, sugars, B vitamins and, of course, caffeine. But how much caffeine? Unfortunately, it’s hard to know. Caffeine itself is rarely listed as an ingredient; instead it’s often lumped into the “proprietary blend” listing. In addition, other ingredients actually contain caffeine. For example, one gram of guarana, a plant extract, provides the equivalent of 40 milligrams of caffeine. Taurine, an amino acid, potentiates the effect of caffeine.

Even if the amount is listed, it can be inaccurate or misleading. While the US Food and Drug Administration (FDA) regulates the amount of caffeine in sodas, it has lax regulatory requirements for energy drinks compared to many other countries (eg, sales of Red Bull in Norway are restricted to pharmacies and completely prohibited in Denmark).

Nonetheless, there are a number of websites you can look to for information on caffeine content of specific products kids might tell you they are drinking (eg, http://bit.ly/QzWxrR ). The caffeine in a single serving size of an energy drink ranges from 80 mg to 160 mg, or nearly two to four cans of soda (Reisig CJ et al, Drug Alcohol Depend 2009;99(1–3):1–10; Blankson KL et al, op. cit). Some energy drinks (eg, Wired X505, ALRI Hypershot) contain more than 500 mg in a single can.

By comparison, here are the caffeine contents in products we’re more familiar with: a 6.5 ounce mug of coffee, depending on how it’s brewed, may have about 100 mg of caffeine; a “tall” Starbucks drip at 12 ounces may have closer to 250 mg; a cup of tea about 50 mg; a 12-ounce can of soda usually between 35 mg and 55 mg; one tablet of Anacin has 32 mg of caffeine; Excedrin has 65 mg; and NoDoz has 200 mg.

Effects of Energy Drinks

There hasn’t been much research on the effects of energy drinks on kids. Lab studies in adults have shown that energy drinks may help with attention and psychomotor skills such as reaction time in driving tests, but effects on long- and short-term memory, complex cognitive function, and athletic performance have been mixed—likely reflecting the wide variety of energy drink formulas tested.

To get a sense of the positive or negative effects of energy drinks on kids, we have to look at the pretty extensive literature on caffeine in kids. It’s not always clear how applicable these studies are to energy drinks, which have so many ingredients in addition to caffeine.

Energy Drinks and Physical Health

The best review of energy drinks’ effects on kids was published as a report by the American Academy of Pediatrics (Committee on Nutrition and the Council on Sports Medicine and Fitness, Pediatrics 2011;127(6):1182–1189). The group strongly discouraged use of energy drinks and other sources of caffeine in kids, for several reasons:

• Potential side effects of caffeine. Caffeine does what you would expect a stimulant to do: it increases anxiety, arousal, vigilance, blood pressure, heart rate, tremor, and motor activity and decreases hunger and sleep. In general, small positive effects may be seen at lower doses (1 mg to 3 mg/kg, which translates to 70 mg to 210 mg for a 155-pound adult, or 35 mg to 100 mg for a 75-pound child) while negative side effects usually override any positive effects at higher doses.


• Troubling evidence from increasing emergency room visits. The number of emergency room visits and calls to poison control centers involving energy drinks has increased in recent years. In very young kids (under 6), consumption of energy drinks is usually accidental. About twelve percent of older kids will be hospitalized for an energy drink-related emergency room visit and, in rare cases, toxicity can be fatal. Caffeine intoxication, per DSM-5, can present as severe anxiety, agitation, restlessness, insomnia, nausea and vomiting, tremors, dizziness, racing heart, and chest pain. Kids who don’t drink caffeine regularly can experience this at doses less than 3 mg/kg or less than 100 mg for a 75-pound child—the equivalent of two cans of soda or less than one energy drink.


• Potential for obesity and dental decay due to sugars added to such drinks. When kids choose energy drinks and other caffeinated drinks, they are replacing healthier drinks such as milk and water with these high calorie and sugar-filled substitutes, leading to both weight gain and cavities.

Energy Drinks and Psychiatry

In terms of psychiatric issues, there’s not much real evidence to hang our hats on. But here are a few things we can be reasonably certain of:

• Potential for addiction to energy drinks. For those of us who drink coffee regularly, we know it can be hard to go cold turkey. The same can be said for kids drinking energy drinks, who experience the same uncomfortable withdrawal effects of headache, tiredness, sleepiness, miserable mood, and irritability.


• Caffeine tends to worsen symptoms of anxiety in kids. We probably don’t need a study to know that a stimulant such as caffeine from energy drinks can worsen anxiety. But, there is a study of 53 kids between 7 and 17 years old, in which depressed kids were more likely to drink caffeinated drinks and when they did, they experienced more anxiety (Whalen DJ et al, J Pediatr Psychol 2008;33(4):358–67).


• Kids who drink energy drinks later in the day may have insomnia. Kids who drink caffeine have shorter overall sleep time, take longer to fall asleep, and are awake more during the night once they do fall asleep (Roehrs T & Roth T, Sleep Med Rev 2008;12(2):153–162). This can lead to a vicious cycle of increased consumption to stay awake during class, in turn leading to chronic sleep issues. In addition, in adults caffeine decreases slow-wave sleep and changes rapid eye movement (REM) sleep patterns, both of which are critical for learning and memory consolidation. Although there are no studies on sleep architecture and caffeine in kids, it’s likely that they respond to caffeine in similar ways. Therefore, look for concentration and memory issues in children who are big caffeine drinkers.


• Are kids using caffeine to self-medicate ADHD? Ask kids with ADHD whether they use caffeine to improve their focus, because many of them do, and potentially in unhealthy quantities. Caffeine as an ADHD treatment isn’t well studied but based on the limited data it seems that low to moderate doses (<150 mg/day) may be helpful and better than placebo (but not as good as stimulants) in the disorder. But caffeine at doses higher than 150 mg is probably not effective (Leon MR, J Atten Disor 2000;4:27­–47). Kids and their parents should know about these data so they can make informed decisions about what their kids are consuming.


• Some kids will combine energy drinks with alcohol. This can lead to increased alcohol consumption and with potential alcohol poisoning. A recent survey of a national sample of 1,031 people between 13 and 20 years old found that from 48% to 58% consumed caffeinated alcoholic drinks in the previous 30 days (Kponee KZ et al, Addict Behav 2014;39(1):253–258). When mixing energy drinks and alcohol, kids may not feel the effects of the alcohol and will continue to drink. This has resulted in higher rates of alcohol-related problems including being taken advantage of sexually, being or riding with an intoxicated driver, and being hurt or injured.

CCPR’s Verdict: Bottom line: Caffeine is a fact of life, and in moderate doses is unlikely to be dangerous for most older kids or adults. But counsel your patients about the dangers of energy drinks, because their caffeine content is hard to determine, and they have associated health risks.