Caffeine: The Most Widely Consumed Mind-Altering Drug

Caffeine is the most widely-consumed mood-changing drug in the world, with adult “users” consuming an average of 200mg a day. But could it be causing us harm? Zoe Cromier investigates.

- Zoe Cromier

Every day, around 80-90% of adults and children consume caffeine in one form or another – in coffee, tea, fizzy drinks, chocolate and more. Not only is it ubiquitous – truly the world’s most popular drug – it’s spectacularly habit-forming: a morning without coffee can feel like existing in the hinterlands of awareness, groggy shuffling at our desks nothing more than time ill-spent.

Although there are many definitions of addiction, truly addictive substances are not only habit-forming but produce physical withdrawal symptoms when users quit. Caffeine certainly seems to fit this category: the worst physical ache I’ve ever experienced owing to a drug occurred the day I attempted to go cold turkey from caffeine. The headache was unbearable and only alleviated by a desperate dose of coffee (both water and paracetamol proving ineffective).

ADDICTIVE SUBSTANCE

Modern academic opinions on the meaning of addiction vary and there’s much hair-splitting, but yardsticks include a chemical’s capacity to produce dependence (an insatiable need for a substance), tolerance (long-term use results in the capacity to consume ever larger amounts) and reinforcement (the more you take it, the more you want it). Caffeine meets all these criteria.

But just because caffeine is addictive, does that mean it’s harmful? In the 1940s, experiments by Swiss pharmacologist Peter Witt found that different drugs had various alarming effects on a spider’s ability to spin a web. In 1995, Nasa repeating the experiments with speed, marijuana, chloral hydrate and caffeine, the latter resulting in the most mangled web, hinting at toxic neurological effects.