Adolescence is a time of "great risk taking and opportunity" because of changes that occur in brain development, according to Dr. Jay Giedd, writing in the Journal of Adolescent Health. Changes in the brain during the teen years affect cognition, emotion, and behavior.

Dr. Giedd's study is the result of the National Institute of Mental Health's Longitudinal Brain Imagining Project, begun in 1989. About 2,000 people are undergoing brain imagining scans every two years as well as neuropsychological and behavior assessments and DNA tests. The 387 subjects ages 3 to 27 are serving as models of brain development.

Gray matter in the human brain increases in volume until the early teens, and then decreases through old age. During adolescence, brain development is a refining process, with increased connectivity and integration of disparate functions, changing reward systems and frontal/limbic balance, Dr. Giedd writes. The brain's "executive functions" increase during adolescence. Executive functions might include the regulation of emotion, response inhibition, organization, long-range planning, and the ability to pay attention.

"The teen brain is not a broken or defective adult brain," Dr. Giedd said. However, the changes and the "enormous plasticity" of the adolescent brain may make teenagers more likely to take risks and seek new sensations and experiences.

Read more about how a teen's brain development is linked to drug use in this article: "Brain's Executive Control Function Linked to Substance Abuse in Teens"

Labels: brain_chemistry, development, substance_abuse