Junior's been helping himself to Mother's little helper. That's the conclusion of a report released Wednesday by White House drug czar John Walters that found while U.S. teenagers' use of marijuana is declining, their abuse of prescription drugs is holding steady or in some cases increasing.

"The drug dealer is us," said Walters, the national drug policy director.

Walters said that many teenagers are obtaining drugs over the Internet, getting them free from friends or taking them from someone's medicine cabinet.

According to an analysis of national surveys prepared by Walters' office, 2.1 million teenagers abused prescription drugs in 2005, the most recent year for which figures are available.

While their use of marijuana declined from 30.1 percent to 25.8 percent from 2002 to 2006, use of OxyContin, a painkiller, increased from 2.7 percent to 3.5 percent over the same period. Use of Vicodin, another painkiller, increased slightly from 6 percent to 6.3 percent.

Teens are also abusing stimulants like Adderall and anti-anxiety drugs like Xanax because they are readily available and perceived as safer than street drugs, Walters said.

Walters said adults should keep track of prescription drugs and throw them out when they expire.

"People just aren't aware that they need to be careful, and so they leave prescriptions in the medicine cabinet and they don't think anything about it," he said.

The report is based on the 2005 National Survey on Drug Use and Health, a survey of 68,308 families, and the 2005 Monitoring the Future Survey of 50,000 eighth-, 10th- and 12th-graders conducted by the University of Michigan.

Dr. Terry Horton, the medical director of Phoenix House, which operates nearly 100 substance abuse programs in nine states, said the belief that prescription drugs are safer than street drugs is false.

"These medicines cause dependence and addiction when misused and have the potential to cause death," he said. "We're talking about medicines that are related, pharmacologically, to heroin and have very similar effects."