Monitoring the Future is an ongoing research program which annually surveys high school seniors and also performs followup surveys of previous high school classes. This study used five different questionnaire forms to examine illicit and licit (alcohol and nicotine) drug use among U.S. college students and their age-peers not in college. The findings suggest little difference between young adults enrolled in college versus those who were not enrolled, in their annual prevalence of any illicit drug use, use of any illicit drug other than marijuana, or use of any illicit drug other than marijuana or stimulants. College students were also average for their age group in their annual prevalence rate for marijuana, although their rate of current daily marijuana use was half that of their age peers. Use of "crack" cocaine was distinctly lower among college students. College students rated slightly below noncollege-age peers in annual usage rates for lysergic acid diethylamide (LSD), opiates, barbiturates, tranquilizers and methaqualone. College students rated slightly higher annual prevalence of alcohol use, a higher monthly prevalence and a lower daily prevalence. Much lower smoking rates were observed in college students. The previous sex differences in college men's and women's smoking appeared to narrow, possibly due to random fluctuation. (BHK)