The National Household Survey on Drug Abuse is an annual survey sponsored by the Substance Abuse and Mental Health Services Administration. In 1999, a majority of youths aged 12 to 17 perceived great risk from smoking marijuana or using LSD, cocaine, or heroin once or twice a week. Females were more likely than their male peers to perceive great risk from using marijuana once or twice a week. White youths were generally more likely to perceive great risk from using illicit drugs once or twice a week than youths from other racial/ethnic groups. American Indian/Alaska Native youths were less likely than youths from other racial/ethnic groups to perceive great risk. Perceptions of great risk from using marijuana and cocaine once or twice a week significantly decreased from 1994 to 1999. Youths who perceived great risk from smoking marijuana once or twice a week were less likely in 1999 to use substances than youths who perceived less risk. Figures, notes