The students were chosen randomly. They all attended the University of Oviedo. Findings indicated that during the 12 months before the survey, 91 percent of the students had used alcohol, 57 percent tobacco, 17 percent cannabis, 9 percent tranquilizers, 5 percent amphetamines, 2 percent cocaine, 2 percent hallucinogens, 1 percent opiates, and 0.6 percent volatile solvents. At some time in their lives, 96 percent of the students had used alcohol, 70 percent tobacco, 31 percent cannabis, 19 percent tranquilizers, 15 percent opiates, and 3 percent volatile solvents. Both male and female students had begun using volatile solvents early in life. The age of first cannabis use for the majority of users was between 16 and 18. The users of other illicit drugs covered by the study had not begun using them until they were 18 or older. Table and 5 references.