Adolescents may be more vulnerable to drug, alcohol and tobacco addiction, not just because of social factors, but also due to the way their growing brains are wired.

That is the conclusion of an article published in the American Journal of Psychiatry that reviews 140 studies of addiction, adolescence and brain structure in humans and animals. The article says the organization of the adolescent brain -- which lends itself to highly motivated exploration of the world, in order to learn how to be an adult -- may also make it particularly vulnerable to addiction.

"A lot of our research on addiction is focused on, how do you cure it?" said R. Andrew Chambers, assistant professor of psychiatry at Yale University and lead author of the study. But curing addiction "may be harder to do than preventing it in the first place."

Knowing how adolescents are vulnerable to addiction could lead to new treatments, drug and nondrug, and new methods of prevention, Dr. Chambers said. Particularly vulnerable adolescents might receive special preventive efforts.

In most instances, addictions to nicotine, alcohol and illicit drugs begin in adolescence or young adulthood, Dr. Chambers said.

Moreover, he said, more studies should be done on the possible effects of psychiatric medications on the vulnerability of children to addiction, since these medicines affect the same brain systems undergoing development as addictive substances.

While some studies have said stimulants may make children with attention deficit hyperactivity disorder less likely to fall prey to addictions, he said, far more research should be done.

During adolescence, Dr. Chambers said, "motivational systems in the brain go through changes" that propel adolescents to learn how to be adults. "Instead of playing with a toy car," as they may have as small children, "they go out and drive a car." Novel experiences are particularly motivating to adolescents, who are learning what Dr. Chambers calls "motivational repertoires," or skills and interests they will retain for the rest of their lives.

But this impulse toward novelty in the adolescent brain, and its extreme "plasticity," or ability to change in response to experience, make adolescents more vulnerable to addiction than adults. As the adolescent brain seeks to specialize in rewarding activities, addictive substances can crowd out other activities, shrinking the repertoire being learned, the paper says. "When you're addicted," Dr. Chambers said, "all your motivation gets funneled into seeking or taking the drug."

David Lewis, a professor of psychiatry at the University of Pittsburgh, and a deputy editor of the American Journal of Psychiatry, said the research helps tie together strands of research into addiction and the adolescent brain. But he noted that complex social factors also contribute to addiction.

The study was funded by a grant from the Veterans Administration Special Neuroscience Research Fellowship, and by other organizations including the National Alliance for Research on Schizophrenia and Depression, and the National Institute on Drug Abuse.

TOP OF THE PAGE

Find a Drunk Driving Lawyer