Hello doctor, I am 24 year old girl. I used to drink lot of coffee and tea before (until 20 years of age). But after 20 years of my age I started developing jitters if you drink coffee. I also get the same feeling when I take caffeine tablets as most of the tablets for cold relief and painkillers contain caffeine. So I completely stopped having coffee/tea/dark chocolate/caffeine tablets. Now I really want some remedy for this. Please tell me why am I facing this problem? What might be the reason and what is the treatment for this?