Teens' Brains Lack in Ability
for Sound Judgment

by Mara Rose Williams
The Kansas City Star

KANSAS CITY, Mo. - On the outside, teen-agers appear to be nearly grown up. But inside the skull, a vital part of their brain is closer to a child's than an adult's.

New findings in neuroscience and pediatric psychiatry link brain immaturity to teens making foolish judgments and reckless decisions.

Some teens have sex too soon. Some experiment with drugs and alcohol. Some see how far their car will fly on a hilly road.

Adults have long been puzzled about why otherwise "good" kids -- smart kids -- take deadly chances. But now scientists have made a connection. They have discovered that one of the last parts of the brain to mature is the prefrontal cortex -- the very part responsible for self-control, judgment, emotional regulation, organization and planning.

"The teen-age brain is a work in progress," said Sandra Witelson, a neuroscientist at McMaster University in Hamilton, Ontario, who has done research on the subject.

The old belief was that by the time a child reached the age of puberty and pimples, his brain's hardware was completely connected.

But by using magnetic resonance imaging, researchers got pictures that helped prove that the brain has a good deal of developing to do well beyond the start of adolescence.

The brain does reach about 95 percent of its maturation by age 5. But the corpus callosum, a cable of nerves that connects the right and left halves of the brain, continues growing beyond 20-something. The corpus callosum is linked to intelligence, consciousness and self-awareness.

The prefrontal cortex matures the most between the ages of 12 and 20.

Add to this brew of disconnected neurons a healthy dose of active hormones spiked with the power of peer pressure and a need for autonomy and you get a recipe for teen-age behavior that at times is risky at best.

Leawood, Kan., resident Barb Kane said she grew up in a small town where there was little to do but test your limits experimenting with drugs and driving cars too fast.

She said she still thinks about some of the "just plain stupid things," even dangerous things, she did as a teen-ager.

"At the time we were doing them, we didn't think about it being dangerous. You just did it. But as parents now, we stay close to our kids because we know it's tough being a teen-ager today. There's a lot out there that's scary, even in the suburbs," said Kane, whose 14-year-old daughter is a high school freshman.

The research says that after puberty, a pruning process takes place in the prefrontal cortex. About the age of 10, the prefrontal cortex goes through a growth spurt when neurons grow new connections. But those connections die off if they are not used.

The pruning allows the brain to work more efficiently, researchers say. But until that process is completed, most young people don't have all the brain power needed for good judgment.

One result is that many teens cannot walk away from risky activities when they are being coaxed by their peers.

Michael Rapoff, a professor of pediatric psychology at the University of Kansas Medical Center, said most teens lack the skills to resist peer pressure.

"Peer pressure is so powerful that it is difficult to override it by any lecture from adults," he said.

Into a teen-ager's explosive boil of unbridled emotion and temptation, he said, must be added the adolescent feeling of invincibility.

"Actually," he said, "teen-agers are correct in assuming that this is not a very likely time for them to die. So they tend to underestimate risks."

Teens, he said, must be trained to handle peer pressure and to "think before they leap."

Kane, like a lot of other parents of teen-agers, expects a time may come when even her "very level-headed" teen does something foolish.

"Kids will make mistakes and bad decisions," she said "The most we can really do is hope that the mistake they make won't cost them their life."

(edited by David Van Alstyne)

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