Traffic Safety Administration, 2002). Nonetheless, most people acknowledge that these prevalence rates for underage alcohol use are still too high and that the adverse consequences of underage drinking are enormous, as discussed in Chapter 3. The 30-day prevalence rates have hovered at approximately 50 percent throughout the 1990s, and the patterns have been similar for rates of heavy use and daily drinking.

Thus, there has not been a steady decline in underage drinking over the past two decades. Instead, the decline in the prevalence of underage drinking was limited to the period from around 1981 to 1992, and the rates have been relatively stable since then. To explain this period, we can identify three things: a parallel decline in use of illegal drugs, a raise from 18 to 21 in the minimum drinking age across the country, and intensive campaigns to discourage drinking and driving and to encourage use of designated drivers. Peak use in the late 1970s and early 1980s may also be partly explained by the overall culture of youth experimentation in the United States in the 1960s and 1970s, and conversely, changes in the youth culture in the 1980s may have contributed to decreased use of alcohol, as well as illegal drugs. Economic conditions during the 1980s, with reduced resources available to youth, may also have contributed to the marked decrease in drinking.

Substantial evidence suggests that changes in the minimum drinking age laws also contributed to the decline in alcohol use during the 1980s. As noted in Chapter 1, between 1970 and 1976, 21 states reduced the minimum drinking age to 18, and another 8 states reduced it to 19 or 20; however, states began to raise the minimum age to 21 in the late 1970s. By 1984, when the Minimum Drinking Age Act was passed, 23 states had such laws in place. All states had minimum drinking age laws in place by 1988. This trend in implementation of minimum drinking age laws mirrors the national trend in declining alcohol prevalence among youth. Furthermore, research demonstrates a clear relationship between increases in the minimum drinking age and reduced rates of drinking (Wagenaar, 1981; Wagenaar and Maybee, 1986; O’Malley and Wagenaar, 1991; Klepp et al., 1996; Yu et al., 1997). Finally, O’Malley and Johnston (1999), while acknowledging the role of minimum drinking age laws, postulate that other initiatives, such as “zero tolerance” laws and national campaigns aimed at discouraging drunk driving, may also have contributed to the reduction. They observe that these campaigns peaked during a time of the decline in drinking.

In the committee’s judgment, the salient lesson in these trend data is that the decline in underage drinking prevalence in the 1980s is largely attributable to specific interventions, including the increase in the minimum drinking age—perhaps supplemented by a secular decline in substance abuse and the grassroots campaign against drunk driving. We believe that de-