Dopamine is a chemical in your brain that affects your emotions, movements and your sensations of pleasure and pain. Dopamine neurotransmitters are located in the deep middle region of your brain called the substantia nigra. There are five dopamine receptors. The most common disease that exemplifies the loss of the chemical dopamine is Parkinson's. A person living with Parkinson's must replace dopamine with a drug know as L-Dopa, or carbidopa/levodopa.
The substantia nigra is a very important area of your brain that controls your motor symptoms. Within the substantia nigra there are cells that naturally produce dopamine. Dopamine is not only responsible for physical movement, it also affects how someone learns and behaves. Dopamine has been implicated in everything from schizophrenia, to attention deficit disorders, to loss of cognitive reasoning in old age.
The Dopamine Hypothesis is a theory espoused by some scientists working to understand the brain. According to the theory, a schizophrenic person is producing too much dopamine. Scientists take their evidence from clinical trials of people using amphetamines. Amphetamines cause the brain to produce more dopamine and this increase has been directly related to psychotic-like symptoms. While it is generally agreed upon that dopamine has some relation to schizophrenia, it is still unclear as to how much involvement it has, according to Schizophrenia Bulletin.
Dopamine has also been linked to Attention Deficit Hyperactivity Disorder, or ADHD. ADHD is identified in children and adults when they lack proper attention span, exhibit hyperactivity and impulsiveness. ADHD is also more prevalent in boys than in girls. The agreed-upon assumption is that when someone is demonstrating signs of ADHD, receptors in the brain are not responding to dopamine, according to a page at washington.edu.
Decrease in Dopamine
As you age, the loss of dopamine, which regulates pleasure and approval, slows metabolism in the realm of the brain where apprehension is contained. The decrease in dopamine occurs naturally in everyone between the ages of 20 to 80. It is estimated that 6 percent to 7 percent of the receptors that accompany pleasure and approval are lost with each decade, according to the College of Pharmacy at the University of Texas.
Dopamine has the enormous job of regulating mood, behavior, sleep and cognition. It also is associated with motivation and reward. Dopamine helps with decision-making and creativity. When any of the five dopamine receptors are not working correctly, there is a chance that some form of disruption will emerge such as Parkinson's, schizophrenia or ADHD. How the brain functions in its entirety is still a very complicated and often misunderstood area of science.