The world’s most common psychoactive drug is not what you might think. After hearing the words “psychoactive” and “drug” most people immediately think of illegal substances and hippies from the 1960’s. But what you might not realize is that you probably are addicted to a psychoactive substance that you consume every morning: coffee. And in coffee, you’ll find the drug affectionately known as caffeine (yes, even most decaffeinated varieties contain some caffeine).

Caffeine is so common that 90% of people in the world use it in one form or another. In the U.S., 80% of adults consume caffeine every day and the average adult has an intake of 200 mg per day, the amount in two 5-ounce cups of coffee or four cola soft drinks. And it’s not just adults using caffeine: a study of 7th, 8th, and 9th grade students in Ohio found that students consumed an average of 53 mg of caffeine per day, but almost one in five students consumed more than 100 mg of caffeine each day!
So, most people are aware that caffeine makes you more alert but does that really qualify it as a “psychoactive drug”? The answer is a resounding YES! It is a drug because it works as a central nervous system (CNS) stimulant to change the way your brain and body work and also changes how you behave and feel. While a little caffeine has the positive benefit of making you more alert for a while, too much will cause problems and can:
- Make you jittery and shaky
- Make it hard to fall asleep, stay asleep, or get a good night’s sleep
- Make your heart beat faster
- Cause an uneven heart rhythm
- Raise your blood pressure
- Cause headaches, nervousness, and/or dizziness
- And in extreme cases, can lead to death (yes, it is possible to overdose on caffeine)
And just like any drug, you can become dependent on it so that you’ll need more of it to get the same effect. This is referred to as “building up a tolerance”. And also just like any drug, giving up caffeine can cause withdrawal symptoms such as severe headaches, muscle aches, temporary feelings of depression, and irritability. And also like many drugs, the high doesn’t last forever, causing many of us to crave a second cup sometime before lunch. Caffeine levels in the blood usually peak within one hour and linger for about four to six hours.
Question: So, if caffeine is a drug, why don’t I hear about more people overdosing on it?
A toxic dose is roughly 10 grams per day which equates to roughly 50–100 cups of coffee. That’s a lot of coffee! But what’s really troubling is the marketplace trend of highly caffeinated energy drinks, chewing gums, caffeine pills, and pure powdered caffeine, which is available as a dietary supplement. Many of these things are much more potent than your typical cup of coffee. In fact, pure powdered caffeine can be lethal in tablespoon-sized amounts!
There are several cases of documented caffeine overdoses. Here are just a couple of incidents: 1) in 2010 a 23-year-old British man from Mansfield, England died after taking 2 spoonfuls of pure caffeine powder washed down by an energy drink at a party. His death was ruled accidental. 2) In 2007, a 19-year-old named James Stone died after taking over 25 NoDoz (caffeine) pills.
And in case you are wondering how much caffeine you are getting, here are some amounts found in common foods, beverages, and medications:
Size | Caffeine content | |
Brewed Coffee | 8 oz. | 95-200 mg |
Brewed, decaffeinated | 8 oz. | 2-12 mg |
Espresso, restaurant-style | 1 oz. | 47-75 mg |
Specialty drink (latte or mocha) | 8 oz. | 63-175 mg |
Black tea | 8 oz. | 14-70 mg |
Green tea | 8 oz. | 24-45 mg |
Ready-to-drink, bottled iced tea | 8 oz. | 5-40 mg |
Coca-Cola | 12 oz. | 23-35 mg |
Mountain Dew, regular and diet | 12 oz. | 42-55 mg |
5-Hour Energy shot | 2 oz. | 200-207 mg |
Energy drinks, regular or sugar-free | 8.4 oz. | 75-80 mg |
Excedrin Extra Strength | 1 tablet | 65 mg |
NoDoz Max Strength | 1 tablet | 200 mg |
Dark chocolate-coated coffee beans | 28 pieces | 336 mg |