THE TOPICS ADDRESSED BY THE FOUR STUDIES ARE AS FOLLOWS: A DEVELOPMENTAL ANALYSIS OF ANTECEDENTS OF ADOLESCENT INITIATION INTO STAGES OF DRUG USE (SEE NCJ-50621); THEORY TESTING IN LONGITUDINAL RESEARCH ON MARIHUANA USE AMONG ADOLESCENTS (SEE NCJ-50620); PSYCHOLOGICAL PREDICTORS OF EARLY USE, LATE USE, AND NONUSE OF MARIHUANA AMONG TEENAGE STUDENTS (SEE NCJ-50622); AND PANEL LOSS OR SAMPLE ATTRITION IN A LONGITUDINAL STUDY OF DRUG ABUSE AMONG HIGH SCHOOL STUDENTS (SEE NCJ-50623). FOR EACH STUDY, COMMENTS ARE PRESENTED ON THE THEORETICAL FRAMEWORK EMPLOYED, THE GENERAL RESEARCH DESIGN, THE WAYS IN WHICH THEORETICAL CONCEPTS ARE MADE OPERATIONAL, THE RESEARCH QUESTIONS POSED, AND THE WAYS IN WHICH FURTHER ILLUMINATION OF PROCESSES OF CHANGE IN THE USE OF DRUGS MIGHT BE SOUGHT. IT IS CONCLUDED THAT, ALTHOUGH THE THEORETICAL FORMULATION OF THE STUDIES IS LESS THAN PRECISE, UNDERSTANDING OF DRUG BEHAVIOR WILL NOT BE GREATLY ENHANCED BY PRODUCING MORE ELEGANT FORMULATIONS USING STRUCTURAL EQUATIONS. RATHER, THE CAUSES AND CONSEQUENCES OF DRUG ABUSE MUST BE UNDERSTOOD IN TERMS OF THE CHANGING SOCIAL MEANINGS ATTACHED TO DRUG USE AND IN TERMS OF THE DECISIONS INDIVIDUALS MAKE WITH REFERENCE TO THESE MEANINGS AND IN LIGHT OF DRUG AVAILABILITY, SOCIAL TIES, AND PERSONALITY ORIENTATIONS AND NEEDS. THE INTERESTING QUESTIONS LIE IN THE PROCESS THROUGH WHICH NONUSERS ARE TRANSFORMED INTO OCCASIONAL USERS AND OCCASIONAL USERS INTO HEAVY USERS. DATA ON THE FREQUENCY, LEVEL, AND CIRCUMSTANCES OF DRUG USE AT EACH AGE LEVEL AND AMONG SOCIALLY SALIENT SUBGROUPS, INCLUDING SPECIFIC SCHOOL POPULATIONS ARE NEEDED IN ORDER TO ASSESS THE NORMATIVE STRUCTURE OF DRUG USE. A CHART DEPICTING AN ARRANGEMENT OF THE SITUATIONS AND VARIABLES THAT SEEM TO BE INVOLVED IN ADOLESCENT DRUG ABUSE IS PRESENTED. EXAMINATION OF ALTERNATIVE COURSES OF HUMAN DEVELOPMENT AND STUDIES OF THE DECISIONMAKING PROCESSES AND CONSIDERATIONS THAT ADOLESCENTS ENGAGE IN RELATIVE TO DRUG USE WILL NOT YIELD A SINGLE MODEL OF DRUG-USING BEHAVIOR, BUT WILL YIELD CLUES ABOUT CRITICAL PHASES OF THE DEVELOPMENTAL PROCESS. SUCH INFORMATION WOULD BE USEFUL IN DEALING WITH THE SERIOUS DANGERS OF ADOLESCENT DRUG USE. A LIST OF REFERENCES IS INCLUDED. (LKM)