Not the user you asked, but I took 800-1200mg a day for a while. Then I finally went to the doc to find out I was having a depression. So I unconsciously tried to treat my depression, which obviously didn't work out. The caffeine enabled me to get out of bed at all though. Without it I was just sleeping/staying in bed all day. And coming down from a lot of caffeine really makes you feel a lot worse than not taking any at all, just like the comedown of other stimulants.