The top public health problem in the United States is not obesity, as many might guess, says one public policy organization. The National Center for Addiction and Substance Abuse, also known as CASA, leaves no question as to where it stands on the subject, titling its latest study “Adolescent Substance Use: America’s No. 1 Public Health Problem.”

The report released Wednesday finds that the consumption of alcohol, the use of tobacco and marijuana and the abuse of prescription drugs is on the rise among teens.  That’s not terribly surprising but this might be:  CASA found that 9 out of 10 adult addicts started using before the age of 18,  compared with  1 in 25 Americans who started using these substances at age 21 or older.

Another finding: 75% of high school students have used addictive substances with 1 in 5 of them meeting the medical criteria for addiction.

Researchers believe that the adolescent brain is still developing in the areas that lead to decision-making, judgment, impulse control  and emotions, making teens more likely than adults to take risks, which makes them more likely to try things like tobacco, alcohol and other drugs.

The study done primarily through online surveys, gathered information from 1,000 high school students, 1,000 parents of high school students, 500 school personnel and a host of other studies and articles. The final results, released Wednesday found the top 4 substances among adolescents are:

1) Alcohol

2) Tobacco

3) Marijuana

4) Prescription drugs

“These rankings combine availability of these substances with the perception of harm,” says Susan Foster, vice president and director of policy research and analysis with CASA.  In other words, using drugs, alcohol and tobacco is a health risk, but as a young teenager, finding them and getting them also comes with some risk.

So who’s to blame for substance use among adolescents? There’s a lot of it to go around, says Foster. Glamorous alcohol and tobacco advertising gets a ding, as do pharmaceutical ads that present pills for any ills.  The media in general also take a hit for  playing  down or making light of characters who are drunk or high, according to the report. Even parents get a not-so-honorable mention for either looking the other way when their teenagers experiment with addictive substances, or for thinking that this experimenting is just another rite of passage on the way to adulthood.

The problems associated with substance abuse are not limited to health and safety. It’s  also a huge financial drain on our economy. CASA cites the total cost to federal, state and local governments as at least $467.7 billion per year which puts it at almost $1,500 for each American. And these costs largely coming from those teen users, according to CASA.

So what’s the answer? First, parents need to engage their teenagers early and teach them the dangers of playing and experimenting with these types of addictive substance, the report says.   Also, the mass media should be encouraged to back off making tobacco and alcohol such an enticing product.

“CASA wants the health care industry to step in and do their part too,” says Foster. It is urging health care providers to screen for substances and be willing to counsel teens early about preventive measures and intervention.