WRITTEN about 8 years ago…
Background: I don’t drink coffee regularly (anymore). 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.
One, 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 works on, one of which is denoted as A2A. Interestingly, caffeine blocks 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.