Comment by malfmalf

Maybe this is the study? First result in google for "cocaine caffeine comparison"

https://pubmed.ncbi.nlm.nih.gov/25414797/

or this :

https://www.beveragedaily.com/Article/2002/09/02/Coffee-acts... https://www.purdue.edu/newsroom/releases/2016/Q4/mixing-ener... https://www.purdue.edu/newsroom/releases/2016/Q4/mixing-ener...

they seem to imply something similar what you are stating

this one found no such effect on rats:

https://www.sciencedirect.com/science/article/abs/pii/S01497...

and most of the articles I found say that caffeine INCREASES the effect of caffeine