Eric Niiler

In the following viewpoint, Eric Niiler, staff writer for the San Diego Union-Tribune, contends that people are genetically predisposed to addiction—which is why some people can use drugs and alcohol recreationally, while others quickly become addicts. For some, drugs such as heroin, cocaine, and nicotine produce high levels of the brain chemical dopamine, which is associated with pleasure. The surge of dopamine produced by taking drugs is so powerful that addicts find quitting nearly impossible.

As you read, consider the following questions:

1. According to statistics provided by Niiler, what is the respective addictiveness of nicotine, heroin, cocaine, alcohol, amphetamines, and marijuana?
2. According to Niiler, what role does dopamine play in addiction"

Not long ago, brain researcher George Koob was showing slides of experimental rats receiving cocaine to a group of medical workers at UCSD. During the...