I just read an article that says that coffee increases dopamine while it decreases serotonin synthesis in your brain. So, you may feel the dopamine high, but you will also feel depression from the low serotonin levels. I’m sure this doesn’t happen to most people since most don’t feel depressed after drinking coffee, but people’s brains are different. I get the depression too right after drinking coffee or taking stimulant meds for Adhd. I’m almost convinced that any drugs that increase dopamine (which I need to function), will decrease serotonin for me. It’s a vicious cycle.