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Vulnerability to Addiction

Despite the reinforcing properties of drug use, however, many people drink alcohol and/or experiment with illegal drugs without becoming addicts. Only a small percent of users turn into alcohol and other drug abusers, and an even smaller number become alcoholics and drug addicts. For instance, a large proportion of people who use heroin don't become heroin addicts. Scripps Research Institute professor George Koob, M.D., says that for every one heroin addict there are two or three "chippers," individuals who use opiates only on the weekend or less frequently.

Vulnerability Menu:

The Role of Biology and Genetics

"Gateway" Drugs?

"Pretty much everyone enjoys having their dopamine levels shoot up dramatically, which can happen without the use of drugs, as with the 'runner's high,'" says Alan Leshner, Ph.D., director of the National Institute on Drug Abuse. "However, not everybody craves the experience so much that it consumes them." Nor does everyone experience the same changes in brain function.

What makes for the difference between someone who can drink or dabble in illicit drugs without developing dependence or many negative consequences, and someone who becomes an addict? Researchers believe that there is great variability among individuals when it comes to their vulnerability to becoming addicted. Vulnerability is affected by many factors. Leshner says that one of the major predictors of becoming addicted is the level of stress a person is trying to cope with. "The more stress, the more likely it is you will get addicted," he says. But risk of addiction is also driven by the individual's genetic background, other biological factors, the environment, and the social context in which drug use is occurring.

In addition, new studies are showing that many smokers who have been unable to quit are suffering from serious psychiatric problems. Cynthia Pomersleau, Ph.D., with the University of Michigan's Substance Abuse Research Center and Nicotine Research Laboratory, says she has found mounting evidence that smoking is becoming increasingly concentrated in people at risk for major depressive disorder, adult attention-deficit hyperactivity disorder, anxiety disorders, and bulimia, or binge eating and purging. Her link between smoking and psychiatric disorders could yield the development of new types of smoking cessation strategies tailored to treating the psychiatric problem before or at the same time as the smoking problem. The drug buproprion -- already used as an anti-depressant -- is now being marketed for smoking cessation as well, under the name Zyban.

-- Janet Firshein

ANIMATIONS | Differences | Crossing the Line | Relapse | Why Drugs? | Similar Effects | Dependence | Vulnerability | Changing Back | Interviews




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