Comment by crote

And doing "only alcohol" vs "alcohol plus energy drink" research is quite misleading: college kids are using it to mask the taste of alcohol, so it is basically a certainty that they'll drink more alcohol and drink it faster. And because alcohol is bad that will obviously lead to worse outcomes.

If you want to do proper research on the impact of the caffeine part you'd have to do, say, "alcohol with Red Bull" vs "alcohol with Sprite".