Numerous background factors are related to licit and illicit drug use, including educational experiences, employment experiences, and lifestyle orientation indicators. Results from five nationally representative surveys of high school seniors from 1975-1979 were used to document the degree to which such factors are correlated with measures of drug use, the interactive effects on drug use, and changes in youth drug use. Findings indicated that males exceeded females in alcohol and marijuana use; black seniors used drugs less than whites. Other family background dimensions were only modestly associated with drug use. Above average drug use was correlated with high rates of truancy, frequent evening recreation, relatively long job hours, and relatively high incomes. Drug use was below average among seniors with high grades, strong religious commitments, and conservative political views. Shifts in drug use were not accompanied by substantial shifts in the correlates of drug use. The results suggest that young people who are most "at risk" tend to remain the same, while the types and amounts of drugs used tend to shift from year to year. (Author/KMF)