By MIKE MAGEE

Question: What is the world’s most widely used psychoactive drug?

Answer: Caffeine

In the U.S., caffeine is consumed mainly in the form of coffee, tea, and cola. But coffee dominates. Worldwide, humans consume over 10 million tons of coffee beans a year. Roughly 16% (1.62 million tons) is devoured by Americans. The daily intake of caffeine varies depending on type of beverage and brand as the chart below indicates. 

On average, each American consumes approximately 164 mg of caffeine each day. That’s roughly 1 small cup of Dunkin or (3.5) 12-ounce Diet Cokes (Trump consumes at least 12 cans of Diet Coke a day). 

Across the globe, daily consumption of caffeine is close to universal. Eight in 10 humans consume a caffeinated beverage daily. That makes this chemical substance the “most commonly consumed psychoactive substance globally.” Its popularity is related to its ability to deliver three useful physiological enhancements – wakefulness, motor performance, and cognition.

Chemically, caffeine is a close cousin of adenosine which is present in brain neurons. Adenosine builds up in synaptic connections between brain neurons. When it binds to special receptors, it activates neurons that promote sleepfulness. Ingested caffeine is water and lipid soluble, and therefore is able to traverse the blood-brain barrier. Once inside, its chemical structure mimics that of adenosine, and it occupies adenosine receptors because it shares the same approximate shape and size. When these receptors are occupied by caffeine, adenosine molecules are unable to activate the receptors. The net effect is wakefulness.