Alcohol use often begins in adolescence or earlier. By the end of high school, about 75% of adolescents have tried alcohol, and more than half of 12th grade students report having been drunk at least once in their life. Although alcohol use is common, it has very serious consequences. Adolescents who drink alcohol experience negative health and social consequences, including problems with brain development and learning. Alcohol is involved in more than one-third of the adolescent deaths associated with unintentional injury, homicide, and suicide. These 3 causes together are the main causes of mortality in the US adolescent population.