What does coffee do to our brains and why do we love it so much?
As I sit on the Amtrak Acela train 2155, caffeine is coursing through my veins. I made my typical double espresso a quadruple this morning in the interest of spurring my motivation on my 7 a.m. train ride. I am journeying to Penn Station—the New Jersey one, not New York—to visit my sibling. Squeezed inside my red, hard-shell suitcase that is bursting at the seams, is my precious cargo: a bag of Trader Joe’s dark roast coffee grounds.
My older sibling does not suffer from my same caffeine dependence, and for them, a coffee is a bit of a novelty. If there’s coffee provided to them, maybe they will indulge, but there is no coffee in their house… This was a painfully rude awakening upon my first visit. Luckily, however, I learned my lesson. I am now smuggling coffee grounds across state lines. I feel like a member of the Escobar syndicate, but I refuse to travel without my drug of choice.
Caffeine is idolized across the globe and is the most widely used central nervous system stimulant in the world. The substance has myriad pharmacological and physiological effects, as it impacts energy, mood, memory, and both physical and cognitive performance. (About two-thirds of American adults drink coffee each day, making it the most popular beverage, even beating out bottled water.)
The Spring 2025 National Coffee Data Trends Report found that 61 percent of coffee drinkers proclaimed that they believe their drink of choice is good for their health. I would like to formally join this consensus. It’s unsurprising that so many of us believe that our morning brew is beneficial to our physiological well-being; justifying and normalizing our addictions undoubtedly makes us feel better.
For centuries, humans have relished in the enjoyment of coffee, and caffeine is the most widely consumed psychoactive drug in the world. It’s like our brains are made for it. Caffeine molecules are structurally similar enough to adenosine, one of the brain’s “calm down” neurotransmitters. When adenosine binds to receptors in our brain, it causes a decrease in nerve cell activity and makes us feel tired. Caffeine is an adenosine antagonist, meaning that it prevents adenosine from doing its normal job. So, when caffeine enters our systems, it binds to those same adenosine receptors and prevents that drowsy feeling.
This process causes a cascade of neural effects and impacts dopamine, norepinephrine, serotonin, and other neurotransmitters. When caffeine blocks the binding of adenosine, it facilitates dopaminergic neurotransmission—a fancy way to say that more dopamine is being released in our brains. Dopamine is often considered our reward or motivation neurotransmitter and is involved in our feelings of pleasure, alertness, reward, and positive reinforcement.
When we do things that make us feel good, our brains essentially get a hit of dopamine that tells us to keep doing that thing. Addiction is essentially our brains going after that chemically-based euphoria. We love dopamine, we crave it, and we seek it out wherever we can find it. For many of us, we get our fix by way of our morning coffee (and incessant social media scrolling, but that’s a different article).
When explaining my coffee consumption habits, I like to say that I start my day by, “main-lining a double espresso.” So, I know I have a problem. I am an addict.
My typical daily ritual begins with me slinking out of the warmth of my bed, untangling myself from my nest of blankets, and lunging towards my Nespresso machine. I cannot speak highly enough of this beautiful contraption. With the click of a button, I am greeted with the gift of approximately 120 mg of caffeine. How beautiful.
But today, my schedule necessitated an earlier rise. My alarm beckoned, and the harsh glare of the Amtrak ticket, shining far too brightly on my iPhone’s wallet feature, was not enough to get me feeling properly invigorated. A measly double espresso wasn’t going to cut it this morning—my caffeine intake needed exponential growth. I needed a double dose.
I require more and more of the substance in order to experience its desired effects. I have built up a tolerance.
One of the defining features of addiction, clinically referred to as substance use disorder (SUD), is needing an increased amount of the substance in order to achieve one’s desired effects. I am not making light of SUD, but rather drawing some parallels between the words of the DSM and the daily habits that many of us engage in. I undoubtedly have cravings and urges to consume caffeine, and my trip to Trader Joe’s for coffee grounds equated to me spending more time getting the substance. These are other hallmarks of addiction.
If I flip to the SUD page in the DSM, I may be diagnosable. (But hey, if you peruse those pages long enough, you can scrounge up a list of symptoms that fits your character archetype—I’m once again rationalizing my dependence on my favorite drug.) There are, of course, worse substances to be addicted to. My life is not upended or ruined by my addiction. And luckily for me, my cravings are entirely socially acceptable. Coffeeshops serve as one of our primary hubs for social interaction; I’m sure hundreds of thousands of first dates have been conducted at these caffeinated watering holes, and cafés are undoubtedly a primary venue for collegiate bonding.
A few days ago, as I sat in the Boston Public Library’s beautiful reading room, I snapped open a Red Bull and realized I was surrounded by fiends.
The crack of energy drink cans (and the rattle of Adderall bottles) often echoes throughout the room’s vaulted ceilings. Sometimes there is an air of insecurity due to the noise piercing the room’s study atmosphere, but the sounds of tourists shuffling in and out are far more distracting. We all look past the “no food or drink” signs because we know that, between those lines, is a clarification that caffeine is an exception to this rule. We are all united in our caffeine consumption.
Red Bull cans read, explicitly, “enjoyed by college students,” so it feels intuitive to learn that the largest consumer market for energy drinks is young adults. It is estimated that around half of college students consume at least one energy drink a month. A desire to increase energy, reverse the effects of alcohol, and compensate for poor sleep were the primary motives for consumption (sound familiar?). The FDA suggests that for most healthy adults, about 400 mg of caffeine a day is okay. But an iced latte and a Celsius can easily tip you over that amount.
Historically, I am a bit of a coffee snob. I abstain from Starbucks coffee and I’ve never understood the appeal of Dunkin’… Why would I want my coffee sweet? Let me save my sugar crash for later in the day. When I divulged my coffee consumption habits in class, my professor asked me, “How do you deal with the taste of a plain double espresso?”
“I guess I am just a bit sadistic,” I replied.
There’s a chance I don’t actually enjoy the taste, but I’ve spent so many years consuming plain coffee, and getting increasingly addicted to it, that my brain associates the bitter flavor with a surge of dopamine. I’m typically an espresso purist—something my boyfriend quickly learned as I opt for a cappuccino instead of a normal drip coffee (sorry babe, I know the 2-3 dollar price difference adds up.)
Amidst the fervor of finals season, however, I have slipped back into a routine of energy drinks. During my grocery bagging days, I had an energy drink hyperfixation, and I have once again descended into a love for the caffeinated Jolly Rancher juice. While the saccharine taste feels like I am experiencing expedited tooth decay, it is nonetheless delicious, and I love it—like a melted Otter Pop that turns my brain on high. (Spoken like a true addict.)
As we discussed, caffeine hits the brakes on adenosine, leaving us more alert and ready to focus. This hijacking of our sleepiness signals makes caffeine the perfect complement to the frantic sense of stress that accompanies the final days of the semester. Although the brains of most college students are not fully developed, we are largely trusted to make informed decisions that, hopefully, support our wellbeing. If we want to get wired on caffeine, we are well within our rights.
What is incredible, however, is that these cans of rocket fuel are available for anyone to purchase—including kids. Despite the warning labels that attempt to dissuade pregnant mothers and children from consuming energy drinks, my friends and I during our adolescent years did not think twice about indulging. Well, we did have somewhat of an understanding for the severity of these substances because we knew to hide the cans from our parents. We typically indulged in Red Bulls and Monsters on our midnight escapades, sneaking out in eighth grade to go to Safeway to get our fix and 7/11 for slurpees. We thought we were more inconspicuous than we were… Energy drinks were our gateway drugs. Our middle school selves had not yet devolved into the level of high school debauchery we would soon weasel ourselves into. Perhaps it was caffeine that ushered us down this path.
But I will not take complete responsibility for my caffeine dependence, because where’s the fun in that? My father, who hails from Sweden, provided me with a road map of how to consume caffeine. Every morning, for my mom too, starts with a coffee, more specifically an espresso. As kids, we learn to model our parents’ behavior, of course, but I believe I was also bribed. My dad, in addition to being a caffeine addict, is a contractor (his career trajectory should be studied; the Hollywood-costume-designer-to-stay-at-home-dad-to-construction-worker-pipeline is nowhere near commonplace).
He was responsible for driving me to school in my high school years until I was able to drive (and then after I got driving privileges revoked after totaling a car, that’s another story, but in the spirit of not taking responsibility, I thought the truck was slowing down…). As is the case with lots of construction related projects, my dad’s work starts early—he also rises naturally at 5 a.m., perhaps the caffeine cravings have permanently altered his circadian rhythms. As a way to bribe me and quell my impressive level of teenage angst, he got me a cappuccino from Peet’s Coffee every morning. All of the baristas at the local café know my dad by name, and of course his order.
In short, I come by my caffeine addiction honestly. There is basically caffeine surging through my bloodstream. This sentiment rings true on a cultural level, too. Nordic countries, like Sweden, Norway, Finland, and Iceland, have some of the highest per capita consumption of coffee, with an average of approximately 9 kg of coffee consumed annually by each person. Considering that coffee is seen as an appropriate, perhaps expected, beverage at any meal in Sweden, this does not surprise me. Coffee consumption in the U.S. is roughly half of that, clocking in at 4.5 kg per person (roughly three cups per day). You can crunch the numbers, but the data details that Americans drink a lot of coffee, and Swedes drink a lot of f*cking coffee.
As of 2024, the global coffee market is valued at an estimated $269 billion (that’s billion with a B). This number is expected to increase to over $369 billion by 2030. So, if everyone else is drinking coffee, why the hell would I want to stop? Besides structuring your entire life around a substance, spending thousands of dollars on it, and feeling dependent on caffeine, what’s so bad about coffee?
Well, for some, coffee tips their nervous system over the edge. Instead of a pleasant energizing effect, some people are inundated with anxiety. Even for those who enjoy the substance, it is definitely possible to over-indulge. Signs of consuming too much caffeine include: increased heart rate, palpitations, high blood pressure, insomnia or sleep disruption, anxiety, jitters, upset stomach, nausea, and headache.
My addict brain is resistant to the idea of “too much.” Yes, my heart is racing and my palms are sweaty, but my fingers are also typing fast. It’s almost lunchtime and the sound of a cold brew from the café car is calling my name. An additional 220 mg of caffeine on top of my quadruple espresso’s 240 mg… The FDA’s 400 mg limit is only a recommendation after all… I will look past the heart palpitations. And besides, I like to live on the edge.
(I have a serious problem.)