THE INCIDENCE DATA DRAWN FROM SECONDARY AND COLLEGE STUDENT SURVEYS DEMONSTRATE A SUBSTANTIAL, SIGNIFICANT, AND RAPID INCREASE IN THE NUMBER OF YOUNG PEOPLE WHO HAVE TRIED VARIOUS TYPES OF DRUGS AT LEAST ONCE. THESE FIGURES, HOWEVER, TELL NOTHING ABOUT THE PREVALENCE OR PATTERNS OF DRUG USE IN THESE STUDENT POPULATIONS; THEY PROVIDE NO INDICATION OF THE PROPORTION OF USERS WHO TERMINATE USE AFTER ONE OR A FEW EXPERIMENTAL TRIALS, NOR THE RELATIVE PROPORTION OF EITHER THE TOTAL STUDENT BODY OR THE USERS WHO GO BEYOND THEIR INITIAL EXPERIENCES AND ADOPT PATTERNS OF MORE PROLONGED, FREQUENT, OR INTENSIVE DRUG USE.(AUTHOR ABSTRACT)....BDS