I am 18 years and a college student. I was very good in my studies till my school days but lately I have encountered this attention deficit syndrome. I lost all my focus and did not know what to do? My doctor has prescribed adderall for my ailment which I found really benefitting. Last day I was having some real trouble concentrating so I took two adderall doses.I want to know about the adderall overdose symptoms?Can this cause something very harmful?