I am prescribed adderol. I will typically take 5-10mg at a time. Any more, and I get jittery and anxious. Compared to caffeine, it has a lot more stimulative properties. I find that it elevates my mood, and makes me want to conversate a lot. It will cause a decrease in blood flow to the extremities, which will make your hands and feet cold, and i don't know about you guys, but it makes my dick shrink! It definitely gives you the ability to concentrate, even when you are tired, unlike caffeine... I must say, the crash is terrible. It always makes me feel irritable and slightly ill... like i have a low grade fever and I'm run down. Some of my friends would blow over 100mg per day. NUTS I TELLS YA! And these friends prefer adderal to coke. I guess I would too, since I don't like coke at all