A Coffee Drinkers Nightmare: Caffeine Loses It's Kick

Caffeine is a hell of a popular drug. Coffee, tea, various sodas, chocolate covered coffee beans, everybody loves caffeine. Often I will enjoy a cup of coffee merely for the taste sensation of it, but more often than not my reason for drinking coffee is that I'm trying to pick myself up. (I seriously started drinking coffee in grad school, only because I was getting print stains on my forehead from falling asleep over my books so much).

For most people coffee consumption (especially your morning cup of coffee) is motivated by the belief that coffee increases alertness and reverses fatigue.

But the scientific truth is that there may be no true alertness benefit from coffee. Instead, the kick that frequent coffee drinkers get out of their caffeine drink may be little more than relief from their acute caffeine withdrawal (do you ever have those "need-caffeine-headaches"?). Add to this the fact that caffeine has undesirable effects such as increased anxiety and increased blood pressure, and suddenly I'm really annoyed that there is research on this: Damn you scientists! I like coffee. Leave it alone!

Of course nobody really listens to me, so a group of researchers from the University of Bristol is now about to publish a paper in the journal Neuropharmacology that takes a look at the (non-existent) net alertness benefits of caffeine intake: 

By comparing alertness, anxiety and headache syndromes for a stratified sample of caffeine users, and additionally investigating genetic variation in caffeine consumption and caffeine effects, the researchers show that indeed there seems to be little to no net alertness benefits from your morning dose of caffeine.

This is of course not to say that caffeine is not a stimulant. It is. But, as it appears, people quickly build tolerance to the inherent stimulating effect of caffeine, after which it no longer increases alertness. Once this happens, what really keeps frequent coffee drinkers coming back for their fix is avoidance of the negative effects of withdrawal. In other words, instead of the nice push from your early coffee drinking days, all you are left with after you have become tolerant, is the hope of getting rid of that lousy feeling that you get when you haven't had your coffee yet. Coffee now merely gets you back to normal.

On the brighter side, tolerance also seems to build for the (anyway modest) anxiety increasing effects of caffeine, so it's not all bad.

Still, this is sad news to me, and as I now make my way to my local coffee dealer shop I might consider practicing these words: "I am Daniel, and I am an addict".

Main Reference:  

Rogers PJ, Hohoff C, Heatherley SV, Mullings EL, Maxfield PJ, Evershed RP, Deckert J, & Nutt DJ (2010). Association of the Anxiogenic and Alerting Effects of Caffeine with ADORA2A and ADORA1 Polymorphisms and Habitual Level of Caffeine Consumption. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology PMID: 20520601

BTW: If you're interested in genetics there is a lot of interesting caffeine related information in this forthcoming Neuropharmacology paper, but I'm not the one who is going to review it for you. Therefore from the abstract:

“Results showed greater susceptibility to caffeine-induced anxiety, but not lower habitual caffeine intake (indeed coffee intake was higher), in the rs5751876 TT genotype group, and a reduced anxiety response in [medium/high users (MH)] MH vs [non/low users (NL)] NL participants irrespective of genotype. Apart from the almost completely linked ADORA2A SNP rs3761422, no other of eight ADORA2A and seven ADORA1 SNPs studied were found to be clearly associated with effects of caffeine on anxiety, alertness, or headache. Placebo administration in MH participants decreased alertness and increased headache. Caffeine did not increase alertness in NL participants. With frequent consumption, substantial tolerance develops to the anxiogenic effect of caffeine, even in genetically susceptible individuals, but no net benefit for alertness is gained, as caffeine abstinence reduces alertness and consumption merely returns it to baseline.”