The science I present this morning will be particularly relevant to the Drug Addiction Treatment legislation that is the topic of this hearing. Scientific advancs, particularly over the past decade, have catapulted both our understanding and our approaches to addiction. Research has in fact come to define addiction as a chronic, and for many people reoccurring disease characterized by compulsive drug seeking and use that results from the prolonged effects of drugs on the brain. A variety of studies in both humans and animals have demonstrated that chronic drug use does in fact change the brain in fundamental ways that persist long after the individual has stopped taking drugs. By using advanced brain imaging technologies we can see what we believe to be the biological core of addiction.
Brighter colors reflect greater dopamine binding capacity.
The scan on the left is that of a non-drug user, the next is of a chronic methamphetamine user who was drug free for about three years when this image was taken, followed by a chronic methcathinone abuser who was also drug free for about three years. The last image is of the brain of an individual newly diagnosed with Parkinson's Disease. When compared with the control on the left, one can see the significant loss in the brain's ability to transport dopamine back into brain cells. Dopamine function is critical to emotional regulation, is involved in the normal experience of pleasure and is involved in controlling an individual's motor function. It is this change in dopamine that we have come to believe is one fundamental characteristic of all addictions and is at the biological core of addiction.