>>But I feel so much smarter when I drink it.
I think in the short term it would make sense that a stressful, adrenaline producing, situation would be conducive to formation of neural connections (memories); in that such memories would enhance the ability of the organism to cope with similar conditions if encountered in the future.
So I would not doubt what you say, and would not be surprised at a short term increase in "smartness".
The duration of the stressor is an important factor - making the difference between excitement and burnout.