Caffeine: is it all in your head after all?

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Caffeine, as we’ve noted before, is probably the most versatile and powerful legal performance enhancer out there. Researchers can’t seem to find enough good things to say about it. And one of its most head-scratching properties is that it appears to give as much of a boost to habitual users as it does to caffeine virgins. But a new study in the journal Psychopharmacology offers a rare discordant voice. In the words of University of Vermont researcher Stacey Sigmon:

In contrast to what most of us coffee lovers would think, our study showed no difference between when the participant was maintained on chronic placebo and when the participant was stabilized on chronic caffeine administration. What this means is that consuming caffeine regularly does not appear to produce any net beneficial effects, based on the measures we examined.

Backing up for a moment, the study’s main aim was to look at the physiological (as opposed to self-reported) effects of caffeine withdrawal, by measuring brain electrical activity with EEG and brain blood flow with ultrasound. Not surprisingly, they found plenty of symptoms. The withdrawal headaches correlated to increased blood flow, and the fatigue and mood changes correlated with increased “theta rhythm” in the EEG.

To get good data, the researchers had to use an extended seven-week study (with a double-blind crossover design), so subjects spent at least three weeks getting a twice-daily dose of either 200 mg of caffeine or a placebo. This meant that they had a chance to look at the (slightly) longer term effects of being off caffeine for a few weeks. After the initial shock of withdrawal had passed, the researchers couldn’t tell the difference between the signals from the caffeine and placebo groups. Obviously they were only looking at a certain small subset of physical indicators — but the finding is certainly contrary to the expectations of most coffee addicts lovers.