THE GROWING BRAIN MAY MAKE TEENS MORE PRONE TO ADDICTION

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.