Coffee Pot: What Happens When You Mix Marijuana & Caffeine?

You can now add coffee to the growing list of foods and drinks that are available as products infused with marijuana. But what happens when you combine two psychoactive substances: marijuana and caffeine? The effects of using these two substances in combination have not been heavily researched, said Dr. Scott Krakower, the assistant unit chief of psychiatry at Zucker Hillside Hospital in New Hyde Park, New York.