Based on the definition of emotional arousal, stress isn't 100% accurate, but perhaps better than aroused.
Too late to edit the title now, but for the benefit of next time, I'm still interested in suggestions.
> Consumed together, caffeine and theanine exert similar cognitive effects to that of caffeine alone, but exert opposite effects on arousal, in that caffeine accentuates and theanine mitigates physiological and felt stress responses.
This is inline with the anecdotal evidence about theanine's mitigating effect on caffeine & stress.
If I had drank the same amount of coffee I'd've needed to lay down. It was great for all nighters playing Halo multiplayer.
All this time I thought tea's superiority was due to it having "more hydration" or something. This is so interesting to know!