Yes, sometimes, a lot of the time actually, my brain feels very active. Medication that soothe your mind can be Ativan or Xanax (sedatives). However, they are not prescribed all the time. They are addictive to a degree, but if you have very bad anxiety, Ativan and the like can help when you're feeling really bad. You might find someone who would prescribe that for you. I wouldn't necessarily recommend it though for everyone, unless you are really anxious/suicidal.

There is one other way I know you can lessen an overactive brain. Meditation can be extremely helpful. =)

Oh, and sometimes marijuana can help an overactive brain. that's one other medication. It can really help you not to think so hard on one subject.