"Addictive substances also adversely affect brain development and maturation in the areas related to motivation, judgment, inhibition and selfcontrol.26 As a result, addictive substances impair the judgment of teens in the face of potential rewards, leading not only to their engagement in risky behaviors--such as driving while under the influence of alcohol or other drugs or participating in unsafe sexual practices--but also to continued use of addictive substances despite negative consequences.27

Source

Adolescent Substance Use: America’s #1 Public Health Problem," The National Center on Addiction and Substance Abuse at Columbia University (New York, NY: National Center on Addiction and Substance Abuse at Columbia University, June 2011), p. 13.
http://www.casacolumbia.org/a…