Examining substance use rates over a 30 day period, we estimated prevalence figures by coding all individuals as having used or not used a particular substance during this time, regardless of general use history. The first and last intervals consist of four years and the intervening intervals focus on three years each. Smoking prevalence declines only slightly. Alcohol and marijuana use in the 1976 to 1979 interval is greater in urban areas. Thirty day smoking prevalence is higher in rural areas at the beginning of the period.
Amphetamine use drops steadily over the years and is slightly more prevalent in rural areas.
Rural students also score slightly higher in cigarette use during the first three intervals with an even greater difference for the final two intervals. The numbers generated by the research suggest that rural students are at risk. Rural cigarette use rises steadily throughout the full period analyzed. Again, not all of the differences we have discovered are statistically and demographically significant. With the exception of cigarette use, prevalence rates for most substances have declined relatively steadily from about 1976 through 1992 in both urban and rural areas.