Studies show that with the exception of cigarettes, the use of drugs and alcohol among adolescents in general has been dropping since the mid-1980's. Generally, differences in adolescent substance use based on population density alone are relatively slight. Research suggests, however, that inner-city neighborhoods and other areas where ethnic minorities live separately from the greater society may experience higher levels of drug use. Among various ethnic groups, Native American youth report the highest level of drug and alcohol use, followed closely by whites, then blacks and Asians, with the various groups of Hispanics falling somewhere in between. Minority youth are often more susceptible to the negative consequences of substance use, and adolescent boys are more likely to abuse illicit substances than are girls, with larger differences emerging with respect to heavy usage of certain substances such as alcohol. Conclusions about substance use and abuse rates, especially for subgroups such as those based on ethnicity or population density, must be considered within the context of the limitations of the studies, which may be unintentionally biased by differential dropout rates and absenteeism, the lack of data from alternative settings for youth, panel loss, and the problems of self-report in general. 71 references