That's a long-term adaptive effect (you almost make it sound as if caffeine is ineffective at blocking adenosine, which is obviously false). I'm interested in the immediate effect.
That's what I was getting at though, the "immediate" effect could be non-existent because you already have adapted a tolerance (early as 10 days by some studies). If not, you should be able to test easily just by judging your mood about 45 minutes after your coffee.
