4. The ABCs of Drug Action in the Brain

The patient told his counselor that he had fallen into addiction by taking more and more drugs over several months. “I used to be able to stop, but now, if I don’t have the stuff, I go crazy. They say it’s in my head, my brain. Somehow it’s changed...” The patient is right. The brain is changed, and to understand that, we need to know how the brain works at the basic level.