"It is by caffeine alone I set my mind in motion. It is by the beans of Java the thoughts acquire speed, the hands acquire shaking, the shaking becomes a warning. It is by caffeine alone I set my mind in motion."
Yeah, you can't get that from what they describe. From what I've gathered in other studies, there often seems a coffee specific effect. I recall reading a study where coffee prevented liver disease whereas green tea did not. Coffee has a lot of antioxidants in it, so I wouldn't be surprised if that was part of the equation.