by Mandy Wintink
I’m going to admit something here, which I have admitted elsewhere, but do so somewhat reluctantly: I like to feel stimulated. In fact, my entire life is built on the idea of having a passion- and purpose-driven existence, which is a formula for stimulation, at least for me. Similarly, I love the energy of the City of Toronto, the exhilaration of competition, and the tantalizing feeling of a good argument. Anyone who knows me well, knows this about me.
What I don’t like is feeling depressed, apathetic, and without purpose. In fact, it devastates me to the point where I feel, myself, as somewhat pointless. But often it is an inevitably flip side to the stimulation I seek so often. Here is an example.
This week has been an incredible week. I had an intensely stimulating weekend of intellectual preparation for a full-day interview on Monday for a faculty position in the psychology department at the University of Toronto. The day itself was rather incredible, for the most part. Questions about pedagogy, science, and plans for future experiential-learning teaching - all wonderful topics in my opinion. On Tuesday, I prepped to teach again and then that night I had a dinner with faculty members as part of my interview. Essentially, I was “on” for several days in a row by that point. When I woke up Wednesday morning, it was different. I felt like I was without a clear purpose, largely because I had just devoted a significant amount of my energy to a very specific goal: get through the interview with flying colors. Wednesday, Thursday, and this morning all met me with a variety of depression-like experiences including tiredness, apathy, sense of purposelessness.
By this morning, “enough was enough” I thought. What can I do about this? The psychopharmacology-interested side of me wanted to experiment, partially in honor of Brain Awareness Week and a series of “self studies” we, at the Centre for Applied Neuroscience just launched. The first one was on “Drugs and Behaviour: How Chemicals Like Alcohol, Nicotine, and Caffeine Make Us Feel”. So, in line with that, I decided to test myself (again).
Background: I don’t drink coffee regularly (any more). I quit over a year ago. I occasionally have a cup of coffee on the weekends and every once in awhile the barista mixes up my decaffeinated order with a regular coffee - and believe me I can tell! Coffee normally does one of two things to me. It either puts me WAY over the edge, has my entire body buzzing, and makes me sick to my stomach with anxiety. The other thing coffee does to my is gives me a “liquid-high experience”, which involves a state of complete bliss, wonderfulness, and a deep sense that life is absolutely amazing and perfect. I yearn for that experience. It reminds me of moments laying a dock in the sun, a good yoga practice, or the time I took anxiety medication for 5 months.
Today, I wanted to test the hypothesis that caffeine can cure my depression. So I walked down to a coffee shop and got myself a soya cortado — espresso-based drinks are the BEST for invoking a liquid high, in my experience. I began sipping all the way out the door, down the street back to my place, and as I continue to type right now. And then BOOM, just as expected (~ 45 minutes for peak caffeine to hit the brain), I am hit with my welcomed liquid inspiration. Bye-bye depression! Beautifully orchestrated.
So why does this happen? Well, scientific evidence suggests that caffeine, although a stimulant, does not appear to work through the dopamine neurotransmitter system, like the other common stimulants, cocaine and amphetamine. Caffeine (and the similar stimulant, Theophylline, which is predominant in tea) appears to work on the adenosine neurotransmitter system. Outside of the brain, adenosine has a role in the basic biochemical energy process as part of the compound ATP (aka adenosine triphosphate). Adenosine is also one of the nucleosides in RNA. But in the brain, it seems to function like a neurotransmitter and plays a role in wakefulness. Adenosine is also responsible for the drowsiness we feel after a period of sleep deprivation. Adenosine has several receptors that it work on, one of which is denoted as A2A. Interestingly, caffeineblocks this specific receptor subtype. More interesting, is that blocking this receptor subtype also shows antidepressant effects in several animal models of depression.
So… did coffee cure my depression today? Most likely.