Aug. 14, 2008 -- Parents who fail to monitor their school-age children's activities and leave prescription drugs within easy reach play a major contributing role in teen drug abuse, according to a new survey.

A report based on the survey targets "problem parents" who make it easy for their teens to smoke, drink alcohol, or use illegal and prescription drugs because they frequently don't know where their children are on school nights, fail to keep their prescription drugs out of reach, and don't talk about the dangers of drug or alcohol abuse.

The report was based on findings from the 13th annual back-to-school survey of teens and parents conducted by Columbia University's National Center on Addiction and Substance Abuse (CASA).

Among the major findings from the survey:

Almost half of 12- to 17-year olds said they routinely left their homes to hang out with their friends on school nights, but only 14% of parents said their kids did this.

A third of the teens with friends who abused prescription drugs said the friends got the drugs from their home medicine cabinets, and another third said friends or classmates could easily supply them.

One in four teens said they knew of a parent of a classmate or friend who smoked marijuana, and one in 10 said this parent smoked marijuana with teenagers.

For the first time, more teens said prescription drugs were easier to buy than beer. The percentage of teens who considered prescription drugs the easiest drug to buy increased by 46% over the previous year.

"Kids are getting these drugs from their homes or from their friends' homes, but there is a tremendous disconnect or denial among parents about this," former U.S. Secretary of Health, Education and Welfare and CASA Chairman Joseph A. Califano Jr. tells WebMD.