ceptional

We live in an era where students, shift workers, and scientists increasingly consume drugs that modify brain activity in order to enhance cognition. Ethicists are right to fret about this as the number of addictive substances with some ill effects proliferates (DeJong et al. 2008). People will use these things regardless whether or not some condemn the phenomenon, so it is important that information is out there about how best to use them.

Caffeine is probably the most widely-used drug for enhancing cognition and productivity. However despite its long history, I have not been able to find a good manual or user’s guide! By a manual, I just mean a description of on what kind of schedule it is best used, given caffeine’s tolerance profile, acute effects, withdrawal symptoms, etc. Here I’ll report a few things I found in the scientific literature, in relation to my own experience.

When I first drank coffee, the effects were perhaps too strong to help me much, because I got some ‘jitters’ and had trouble focussing. But as I gained a bit of tolerance to caffeine’s effects, the jitters faded and the arousal effect became milder but more conducive to productivity. This tendency has in fact been reported in the scientific literature, as a rapid tolerance selective to some negative effects even while positive effects can continue (Evans & Griffiths 1992; Schuh & Griffiths 1997). However after many months of judicious usage during which an afternoon coffee was effective in heightening and prolonging my workday productivity, I gradually became a daily user. After approximately a year of this, my tolerance to the arousal effects became great enough that I needed a daily coffee simply to feel normal. It still provided a boost, but only to what a year ago I would have considered baseline. In contrast to this important slow rise in tolerance, the academic literature focuses on the very rapid increase in tolerance during the first several days of caffeine consumption. Usually this is measured by decrease in effect of caffeine on blood pressure elevation. Not very useful for understanding how to best enhance cognition.

My situation, in which caffeine no longer had its productivity-boosting effects, must be a very common problem. To solve it, one might either increase one’s dosage, or try to regain the original effects by going off caffeine for a while. I decided to try the latter.

Arvind says that science indicates one can restore complete sensitivity to caffeine after only 5 days of abstinence (or 10 days of gradual abstinence), however I haven’t been able to find a study that documents this. A blood pressure study estimates that only 20 hours of abstinence (Shi et al. 1993) will restore total sensitivity to caffeine on the blood pressure response. But the subjective withdrawal effects don’t peak until nearly 48 hours of absence! Apparently, for different caffeine effects, different amounts of time are required to restore sensitivity. So what about the positive subjective and arousal effects the average person is most interested in?

I decided to go nearly cold turkey for 7 days, with only one or two decafs in that interval to blunt my withdrawal-effect blues. Fortunately, I had only mild headaches, but did have significant lethargy and loss of mental focus. After seven days, I think I have regained most of my caffeine sensitivity. But I’m only on day one of using again, so not certain how close I am to the sensitivity I had 6 months or a year ago. I hope to share Arvind’s experience of increased productivity for a long period before needing to abstain again to restore sensitivity.

Are there any scientific papers on the topic, or lacking that, further personal reports to certify that this works? I worry about chronic tolerance effects that might not dissipate even after prolonged abstinence, but haven’t seen a shred of relevant science. To bring us closer to having a real user’s manual for both caffeine and other cognitive enhancers, those already using should report the results of their self-experimentation!

DEJONGH, R., BOLT, I., SCHERMER, M., & OLIVIER, B. (2008). Botox for the brain: enhancement of cognition, mood and pro-social behavior and blunting of unwanted memories Neuroscience & Biobehavioral Reviews, 32 (4), 760-776 DOI: 10.1016/j.neubiorev.2007.12.001

Shi J, Benowitz NL, Denaro CP, & Sheiner LB (1993). Pharmacokinetic-pharmacodynamic modeling of caffeine: tolerance to pressor effects. Clinical pharmacology and therapeutics, 53 (1), 6-14 PMID: 8422743

Update: this post provides related info in the same spirit.