Jordan Gaines Lewis, Ph.D.

Brain Babble

Why Am I Dependent on Caffeine, and How Can I Wean Off?

Luckily for us, tackling our caffeine dependence may only take one week.

Posted Apr 26, 2017

Makistock/Shutterstock
Source: Makistock/Shutterstock

Hi, I'm Jordan, and I need a daily caffeine fix. (Hi, Jordan!)

Initially, I was drawn to the fun of snatching up seasonal lattes. (That's how they get ya.) Soon after, I appreciated coffee for its smooth taste and irresistible roasty smell. 

But as I started spending more of my time working in a windowless cubicle, I began relying on coffee to not only perk myself up, but also to stay perked up throughout the day. Now I need it every morning.

So, am I too far gone? Why do we become dependent on caffeine in the first place? And is it possible to wean off and get back to "normal"?

First of all, it's important to remember that caffeine is a drug — albeit one that 80 percent of Americans consume daily, in one form or another. By definition, that means that ingesting caffeine causes a physiological change in the body.

In the case of caffeine, a central nervous system stimulant, those physiological changes include increased heart rate, alertness, faster reaction time, and, in larger doses, jitteriness. 

ClockworkSoul (Wikimedia Commons)
Chemical structures of caffeine and adenosine. 
Source: ClockworkSoul (Wikimedia Commons)

To understand caffeine, we must understand another chemical: adenosine. Adenosine is an inhibitory neurotransmitter, believed to play a role in suppressing arousal and promoting sleep. Levels of adenosine rise throughout the day, which may explain why we become increasingly sleepy the longer we've been awake.

Caffeine doesn't work because it activates the brain; rather, it's more that caffeine inhibits deactivation of the brain. Caffeine and adenosine have similar chemical structures, which means that caffeine can bind to adenosine receptors — essentially blocking them, and thus blocking their sleep-promoting effects. 

When people ingest caffeine every day (or, you know, hourly), the body tries to re-regulate itself by creating MORE adenosine receptors ("C'mon lady, you're supposed to be sleepy at 9 p.m."). Regular coffee, tea, and soda drinkers, thus, build up a tolerance to caffeine over time, because we need more of it to plug up all the new adenosine receptors that keep forming. 

Like withdrawal from other types of drugs, caffeine withdrawal can cause tiredness, irritability, and headaches. In more severe instances, people can even experience nausea and flu-like symptoms. 

So how long does withdrawal last, and can we ever get back to baseline?

review of 66 studies by American University scientists suggests that withdrawal symptoms pass relatively quickly: You'll feel worst 20 to 51 hours after your last ingestion of caffeine, and symptoms last between two and nine days, on average. Although harder to study at the cellular level in humans, researchers have found that the number of adenosine receptors in mice returned to normal levels after eight days of caffeine withdrawal in the forebrain (which, among many other functions, controls sleep behavior). After 15 days, however, adenosine receptor levels were still elevated in the cerebellum (the region of the brain responsible for coordinating muscle activity).

In other words, if you can last a week without a caffeinated concoction (and yes, it might feel like a looooong week), you, too, can return, for the most part, to your pre-PSL self.