MAJOR EMPHASIS HAS BEEN PLACED ON THE FINDINGS OF STUDIES WHICH ARE NATIONAL IN SCOPE AND REGIONALLY LIMITED STUDIES WHICH, THROUGH DESIGN OR ANALYSIS, HAVE MADE UNIQUE CONTRIBUTIONS TO THE UNDERSTANDING OF DRUG USE. IT IS CLEAR FROM THE STUDIES SURVEYED THAT THE AVERAGE AGE AT WHICH DRUG USE BEGINS HAS BECOME LOWER, RESULTING IN INCREASING PROPORTIONS OF ADOLESCENT DRUG USERS IN THE UNITED STATES. ALTHOUGH MOST ADOLESCENT DRUG USE IS EXPERIMENTAL, OCCASIONAL, OR ONLY INTERMITTENLY REGULAR, THE PROPORTION OF YOUNG PEOPLE INVOLVED IN PERSISTENT AND MULTIPLE DRUG USE IS SUFFICIENT TO JUSTIFY CONCERN. A VARIETY OF INDICATORS SUGGEST THAT SERIOUS MEDICAL AND PSYCHOLOGICAL SEQUELA OF DRUG USE HAVE INCREASED IN RECENT YEARS. LEGAL DRUGS, WHICH ARE USED MOST WIDELY AND REGULARLY, ARE TIRED AT THE YOUNGEST AGES AND BY AN OVERWHELMING MAJORITY OF ADOLESCENTS. MARIHUANA, THE MOST COMMONLY USED ILLICIT DRUG, IS TRIED BY A LARGE PERCENT OF THOSE WHO HAVE USED ALCOHOL OR SMOKED CIGARETTES, AND ITS USE PRECEDES INVOLVEMENT WITH ANY OTHER ILLICIT DRUG. APPARENTLY, IN RECENT YEARS, A CONVERGENCE OF DRUG USE RATES HAS OCCURRED IN BLACK AND WHITE YOUTH; WHITE ADOLESCENTS SEEM TO BEGIN USING DRUGS AT EARLIER AGES THAN BLACKS, AND THERE IS EVIDENCE THAT THE PREVALENCE RATES ARE SLIGHTLY HIGHER AMONG WHITES FOR USE OF MANY DRUGS. SEX DIFFERENCES IN DRUG USE PREVALENCE HAVE ALSO DIMINISHED. SPECIFIC SOCIODEMOGRAPHIC FACTORS SEEM TO BE ONLY MODESTLY ASSOCIATED WITH DRUG USE, ALTHOUGH AN ASSOCIATION BETWEEN AGE OF ONSET OF DRUG USE AND THE EVENTUAL EXTENT OF INVOLVEMENT IN DRUG USE HAS BEEN SHOWN IN SEVERAL STUDIES. ALTHOUGH PEER GROUP DRUG USE PRACTICES APPEAR TO BE OF MAJOR SIGNIFICANCE IN EXPERIMENTATION WITH DRUGS, OTHER PERSONAL FACTORS SEEM TO BE OF INCREASE IMPORTANCE WHEN DRUG USE IS EXTENSIVE; FOR EXAMPLE, STUDIES HAVE SHOWN THAT PARENTS GREATLY INFLUENCE THE DRUG USE BEHAVIOR OF THEIR CHILDREN THROUGH THE QUALITY OF PARENT-ADOLESCENT RELATIONSHIPS, THE BEHAVIORAL MODELS PARENTS PROVIDE, PARENTAL EXPECTATIONS, AND THE DEGREE TO WHICH DEVIANCE IS TOLERATED IN THE HOUSEHOLD. TABULAR DATA AND REFERENCES ARE PROVIDED. (RCB)