WASHINGTON: (CNN)-Illegal drug use declined among younger teens in the United States last year, but increased slightly among young adults, according to the U.S. government's annual drug use survey.

The use of illicit drugs among 12- to 17-year-olds dropped from 11.4 percent in 1997 to 9.9 percent in 1998. However, among 18- to 25-year-olds, drug use increased from 14.7 percent to 16.1 percent during the same period.

The mixed results in the 1998 National Household Survey on Drug Abuse reflect a continuing widespread drug problem, but a hopeful sign that the anti-drug message may be reaching those in their early teens.