Many studies have documented the use and misuse of alcohol among U.S. college students. As part of the 1999 Harvard School of Public Health College Alcohol Study, investigators estimated the prevalence of student alcohol abuse and dependence, as defined by diagnostic criteria, through a survey of 14,115 students at 119 4-year colleges and universities. More than 40 percent of students reported at least one symptom of abuse or dependence; 31.6 percent met diagnostic criteria for alcohol abuse and 6.3 percent met criteria for alcohol dependence. Students with alcohol dependence, in comparison to those without a diagnosis, were more often male, white, under age 24, unmarried, have parents with college degrees and attend colleges with a high percentage of heavy drinkers. Frequent heavy drinkers were 13 times as likely to be classified with alcohol abuse and 19 times as likely to be classified with alcohol dependence than those who drank but not heavily. Students who engaged in risky behaviors—recent marijuana use, cigarette smoking, multiple sexual partners—or who were heavy drinkers in high school were also more likely to be classified with abuse or dependence. The authors recommend that colleges implement programs for early identification of students with abuse and dependence problems and increase the availability of accessible treatment programs.