Alcohol and drug use is a leading public health problem in most societies. There are several consequences of alcohol and drug use in adolescents that encompass a range of physical, academic, and social problems. Apart from these problems, excessive alcohol and drug use among adolescents is also associated with certain negative consequences and harmful behaviors such as high-risk sexual behaviors (unplanned and unprotected intercourse), sexual misconduct, accidents, fights, and assaults. Among the youth, alcohol use has become a principal factor responsible for high rate of morbidity and mortality. Alcohol and drug use has become the primary cause of death due to injuries in individuals younger than twenty-one years of age. This book explores the patterns of alcohol and drug use among adolescents as well as its impacts on their lives. It will prove to be immensely beneficial to students and researchers in this area of study.