(CBS News) - Drinking and drug use may begin early for a lot of young Americans. A new study shows that by the time most teens reach late adolescence, most of them have drank alcohol and abused illicit substances.
The study, published in the Archives of General Psychiatry, looked at a representative sample of 10,123 teens between the ages of 13 to 18. Researchers asked the teens in person about their drinking and drug habits, and then compared it to lifetime estimates of alcohol and illicit substance abuse.
The results revealed that 78 percent of U.S. teens had drank alcohol, and 47 percent of the group said they'd consumed 12 or more drinks in the past year. When it came to drug use, 81 percent of teens said they had the opportunity to use illicit substances, with 42.5 percent actually tried them.
"Because the early onset of substance use is a significant predictor of substance use behavior and disorders in a lifespan, the public health implications of the current findings are far reaching." the researchers wrote.
A disturbing finding was that 15 percent of the teens met the criteria for lifetime alcohol abuse, and 16 percent could be categorized as drug abusers. The median age for alcohol abuse to begin was 14 with or without dependent behavior. The median age for drug abuse with dependence to start was at the age of 14 and teens who started abusing illicit substances at 15 were less likely to be dependent.
Race may have been a factor in teen alcohol and drug use. Black and other racial and ethnic groups were less likely to have increased likelihood of use with age than Hispanic or white adolescents.
While there were no main gender differences in drug and alcohol abuse for teens age 13 to 16, between the ages of 17 to 18, males had much higher rates for alcohol and drug abuse.
The American Academy of Child and Adolescent Psychiatry warns that the average age of first marijuana use is 14, while alcohol use can begin as early as 12. They also believe that out of the estimated 20 million alcoholics in America, more than half began drinking as teens.