While other surveys seek to measure the extent of substance abuse in the population, the "CASA National Survey of American Attitudes on Substance Abuse VIII: Teens and Parents" probes substance-abuse risk and identifies factors that increase or diminish the likelihood that teens will abuse tobacco, alcohol or illegal drugs. This year, CASA asked a series of questions to examine statistical associations between teen cigarette smoking and teen marijuana use. The troubling findings include: teens who smoke cigarettes are 14 times likelier than those who do not to try marijuana; teens who have tried marijuana and are current cigarette smokers are 60 percent likelier to be repeat marijuana users; teens who are current cigarette smokers are six times likelier than those who have never smoked cigarettes to report that they can buy marijuana in an hour or less; fifty-five percent of teens who are current cigarette smokers report more than half their friends use marijuana; among teens who are repeat marijuana users, 60 percent tried cigarettes first; seventy-seven percent of teens believe that a teen who smokes cigarettes is more likely to use marijuana. Two appendixes contain survey methodology and data. (GCP)