Neurons in the core of the brain release dopamine (DO-pa-meen), a neurotransmitter that affects processes that control movement, emotional response, and the ability to experience pleasure and pain. In people who have Parkinson disease, dopamine-transmitting neurons in this area of the brain die, which causes progressive loss of movement control. A medication called L-DOPA, which the brain can convert into dopamine, often helps control these symptoms. Some researchers have theorized that people with the mental disorder known as schizophrenia * are, in fact, overly sensitive to the dopamine in their brains. Some of these people seem to have been helped by medications that block dopamine receptors in the brain, thereby limiting the neurotransmitter’s effect.
Another class of drugs known as amphetamines (am-FET-a-meenz) work by increasing the level of dopamine that neurons release and then preventing them from taking it back in through the reuptake process. These drugs have medical uses, such as the treatment of attention deficit hyperactivity disorder, but some people misuse amphetamines to help themselves stay awake or perform a task better.