The Addictive Brain

Begin by defining "addiction," which is diagnosed based on characteristics such as abuse, dependence, and craving. Professor Polk then surveys the history of drug use, from ancient history through the development of synthetics in the 19th and 20th centuries. Finally, he reviews government regulation and the substantial costs of drug abuse, both to the individual and to society.

Explore the brain's mechanisms for learning from reinforcement. You'll start with the psychological aspects, discovering the way humans learn by a series of trials and rewards. Then you'll find out what parts of the brain process pleasure, self-control, and craving, and see how the psychology and neuroscience of reward processing converge.

Here you'll examine the ways addiction alters the brain by numbing the pleasure center, sensitizing the dopamine system, and inhibiting the prefrontal cortex. Combined, these altered brain functions lead to strong cravings and a reduced ability to control one's actions. This foray into neuroscience will forever change the way you think about addiction.

Investigate how people may be susceptible to addiction on a genetic level. Thanks to studies of twins and DNA analysis, scientists are homing in on the genes that predispose us toward addiction. While there is no single "addiction gene," our DNA can significantly influence whether we become addicts.