Where the substance comes from
Caffeine comes from coffee, tea, cocoa, kola nut and guarana, but most of the caffeine teenagers consume today is synthetic, added to drinks. A cup of filter coffee holds roughly 80 to 100 mg, an espresso 60 to 80 mg, a can of cola 30 to 40 mg, a 250 ml energy drink about 80 mg — but 500 ml formats hold twice that, and “extreme” drinks far more. Add taurine, glucuronolactone and up to twenty-seven grams of sugar a can.
A little history
Tea has been drunk in China for at least two thousand years and was codified in the eighth century by Lu Yu in The Classic of Tea; coffee, native to Ethiopia, was adopted by the Sufis of Yemen in the fifteenth century to stay awake during night prayers. The coffee houses of Constantinople (1554), Venice, London (1652) and Paris became places of trade and debate that rulers sometimes tried to close. Caffeine itself was isolated in 1819 by the young chemist Friedlieb Ferdinand Runge, at the suggestion of Goethe, who had given him some coffee beans.
The twentieth century industrialised the molecule: Coca-Cola contained it from its creation in 1886, sodas made it universal, and the energy drink was born in Thailand in 1976 with Krating Daeng, which an Austrian entrepreneur turned into Red Bull in 1987. France banned it until 2008; the European Union has required since 2014 the warning "High caffeine content. Not recommended for children or pregnant or breast-feeding women", and the European food safety authority set the 400 mg a day benchmark for an adult in 2015.
Caffeine is today the most widely consumed psychoactive substance in the world, and the only one whose daily use passes for entirely normal — which prevents neither dependence, nor the accidents linked to energy drinks mixed with alcohol, nor powdered caffeine, a few grams of which are enough to kill.
The forms it takes
- Coffee, tea, maté, chocolate.
- Cola drinks and energy drinks.
- Caffeine tablets and gums, pure powders sold online — a teaspoon of which is a potentially fatal dose.
- Pre-workout supplements whose dose is not always declared.
What the user is looking for
Alertness, staying awake through revision or a night out, sporting performance, and a group effect: the can is shared and displayed. Many teenagers drink it not for the effect but because the brand is part of the scenery.
Immediate unwanted effects
- Palpitations, tremor, sweating, anxiety, panic attacks.
- Insomnia: caffeine takes around five hours to halve in concentration, longer in some people. A can at four in the afternoon is still working at midnight.
- Abdominal pain, reflux, diarrhoea.
- Mixing with alcohol: caffeine masks the feeling of drunkenness without lowering blood alcohol. The person feels clear-headed, drinks more, drives. It is the commonest accident mechanism linked to energy drinks.
- Arrhythmia at high dose, particularly in people with an unrecognised cardiac abnormality.
Medium and long-term risks
In adolescents three effects are well documented: shorter, poorer sleep affecting learning and mood; sustained anxiety, in a loop where tiredness calls for caffeine which prevents sleep; and the sugar load, which explains part of the caries and weight gain. Stopping abruptly after daily use produces a real withdrawal syndrome — headache, irritability, fatigue, poor concentration — for two to nine days. Tapering is better.
One or two cups of coffee a day is not a problem for an adult. The question energy drinks raise is different: high doses, in smaller bodies, late in the day, and often alongside alcohol.
How to spot use
Numerous empty cans in the bedroom or bag, falling asleep very late, hard mornings, irritability and headache on days without, reported palpitations, school results falling from lack of sleep rather than lack of work.
Why the effect is stronger in adolescents
At the same dose in a lighter body, the concentration reached is higher in an adolescent than in an adult. More importantly, the reward circuit matures well before the prefrontal cortex that is supposed to restrain it: the pull to repeat is stronger and the brake weaker, which markedly shortens the gap between first use and problem use. Use established before eighteen multiplies the risk of adult dependence whatever the substance — including legal ones such as the caffeine in energy drinks, alcohol or nicotine.
When to call an ambulance without hesitating
Loss of consciousness, seizures, severe confusion, slow or irregular breathing, blue lips, chest pain, very high temperature, uncontrollable agitation, suicidal thoughts. In those situations call the emergency services and say what was taken: treatment depends on it, and nobody is prosecuted for calling to save someone.