The morning cup of coffee: It's what fuels much of America's workforce. But how effective is it? In Seed magazine, writer David Muner reflects on his decades of coffee drinking. His personal experience seems to comport with a recent study in this month's Neuropsychopharmacology. In the study, researchers found that coffee merely helps habitual coffee drinkers gain the alertness that non-coffee drinkers already have:

The researchers deprived 379 people of coffee for 16 hours, then asked them to rate their levels of alertness. Then they gradually give them caffeine. It took habitual coffee drinkers 250 mg of caffeine before they reported alertness levels equal to non-coffee drinkers—so the caffeine only seems to serve to remove withdrawal symptoms. But even in non-coffee-drinkers, the caffeine they consumed didn’t improve alertness. Caffeine doesn’t seem to work for anyone.
Are legions of coffee drinkers wrong about its effects?