High school is often a time when teenagers engage in risky health behaviors ranging from experimenting with drugs and alcohol to driving in cars without wearing a seat belt or riding a bike without a helmet.

The Centers for Disease Control and Prevention's National Youth Risk Behavior Survey for 2009 shows that there are lots of things that large numbers high schoolers do that put them at risk for injury or death from carrying guns to having unsafe sex.

The nationwide survey found that nearly 10 percent of students rarely or never wear seat belts when riding in a car and nearly 85 percent rarely or never wear bike helmets. At least once in the last month, more than 28 percent had driven in a car driven by someone who had been drinking and nearly 10 percent had driven under the influence of alcohol.

One in five students in the survey had smoked cigarettes at least one day in the last month and 11.2 percent smoked daily during that period. Nearly 42 percent of students drank alcohol within 30 days and nearly one in four had had five or more drinks at one sitting in that period. One in five of the students smoked marijuana at least once during the month they were surveyed. In addition, one in five students had taken a prescription medication – Oxycontin, Percocet, Vicodin or Ritalin) meant for someone else during that period.

"We are concerned to learn that so many high school students are taking prescription drugs that were not prescribed to them," said Howell Wechsler, director of the CDC's division of adolescent and school health.  "Some people may falsely believe that prescription drugs are safer than illegal drugs, yet their misuse can cause serious adverse health effects, including addiction and death."