I am very hyperactive, but it hasn't been this way since early childhood. I am now 18 and I have been experiencing this since I was about 14. I really can't sit still and always have to be moving, and at times, I feel so euphoric and energized that I feel I am losing control. I do strange behaviors without thinking, like dancing around and saying odd things. It often frightens the people around me as well; they say it seems like I am on drugs when this occurs. What could be the cause of this?