This 15th annual "back-to-school survey" continues the unique effort of The National Center on Addiction and Substance Abuse (CASA) at Columbia University to track attitudes of teens and those, like parents, who influence them. Over a decade and a half, through this survey the researchers have identified factors that increase or decrease the likelihood of teen substance abuse. Armed with this knowledge, parents, teachers, clergy, coaches and other responsible adults are better able to help this nation's teens grow up drug free. The QEV Analytics survey reveals that the drug-free school gap between public schools and private and religious schools is up sharply from its narrowest point in a decade. In the 2001 CASA's back to school survey, 62 percent of public school students and 79 percent of private and religious school students said they attended drug-free schools; in this year's survey, 43 percent of public school students and 78 percent of private and religious school students say they attend drug-free schools, widening the drug-free school gap from 17 points to 35 points. The most disturbing finding of the trend analysis this year is this: the percent of children in drug-infected middle schools--usually kids 12- to 13-years old (and younger)--has increased from 23 percent last year to 32 percent this year, a jump of 39 percent. This year's survey underscores how vital it is for parents to know about their teens' friends. Friends are teens' number one source of marijuana. Teens who drink and use drugs are more likely to be hooking up. Seventy-five percent of teens report that the teens they know who drink alcohol or use illegal drugs are more likely to engage in sexual activity. Appendices include: (1) Survey Methodology and Sample Performance; (2) 2010 CASA Survey of Parents of Teenagers Weighted Frequencies (Knowledge Networks); (3) 2010 CASA Survey of Teenagers, 12- to 17-Years Old Weighted Frequencies (Knowledge Networks); and (4) 2010 CASA Survey of Teenagers, 12- to 17-Years Old Weighted Frequencies (QEV Analytics, Ltd.). (Contains 29 figures and 6 tables.) [This survey was conducted by the Knowledge Networks QEV Analytics, Ltd.]