Adolescent drug use increased until about 1981, but since then it has steadily declined. Current data show some drug use in the 4th and 5th grades and considerable increases from the 6th to the 9th grades. For drugs such as marijuana, cocaine, and stimulants, lifetime prevalence continues to increase through high school; for drugs such as inhalants and heroin, lifetime prevalence may decline for Grades 10, 11, and 12, suggesting that students who use these drugs early may drop out. Drug use of rural youth is similar to that of other youth. Barrio, ghetto, and Native-American reservation youth may have high rates of use, but use of Black and Hispanic seniors may be equivalent to or less than that of White seniors. National data and broadly defined ethnic data, however, may cover up important subgroup differences. For example, Western Mexican-American girls have lower use than Western Spanish-American girls, possibly because of the greater influence of "marianisma." Different locations may also have very different patterns of adolescent drug use, calling for different types of local intervention.