The nicotine in tobacco products poses a significant danger of structural and chemical changes in developing brains that can make teens more vulnerable to alcohol and other drug addiction and to mental illness, according to Tobacco: The Smoking Gun, a new white paper released this week by The National Center on Addiction and Substance Abuse (CASA) at Columbia University. The paper was commissioned by The Citizens´ Commission to Protect the Truth, a group of all former U.S. Secretaries of Health, Education, and Welfare and of Health and Human Services, all former U.S. Surgeons General, and all former Directors of the Centers for Disease Control and Prevention.