MLDA laws in the US are still controversial, and though the vast majority of previous studies have found that changing MLDA’s did affect the frequency of heavy drinking, alcohol-related traffic crashes, and suicide among persons in the targeted age groups of 18 to 20, there have been recent claims that stricter MLDA laws may have worsened the incidence of clandestine binge drinking or other drug use, especially on college campuses (e.g., DiNardo and LeMieux 2001; Amethyst Initiative 2008), and concerns that stricter laws might have reduced the opportunities for ‘apprenticeship’ in responsible drinking (e.g., Rehm et al 2003). However, in the present study, we find that exposure to a younger legal purchase age is associated with more than a 30% increase in the odds of a past-year alcohol use disorder, even among respondents evaluated in their 40’s and 50’s. Remarkably, earlier MLDA exposure also predicts elevated risk for a past-year drug use disorder in middle adulthood. Approximately 51.8% of adults in our target cohort would have been allowed to purchase alcohol before the age of 21, and we found that
