Five brain chemicals act together to call the brain to attention and produce a sharp attentive state: acetylcholine, dopamine, histamine, norepinephrine, and serotonin. Any imbalance in production or distribution of any of these will zap the brain’s ability to act alertly. (Stimulants such as amphetamines and cocaine act on all of these except acetylcholine.) (Guiffre, Kenneth, MD, with Theresa Foy DiGeronimo. The Care and Feeding of Your Brain. p 30-39. NJ:Career Press, 1999.)