"Drug use, including the abuse of prescription medications and underage drinking, significantly affects the health and well-being of the Nation's youth and young adults. Substance use affects academic performance and military preparedness and is linked to crime, motor vehicle crashes and fatalities, lost productivity, and increased health care costs. Stopping use before it begins can increase an individual's chances of living a longer, healthier, and more productive life. Put simply, drug prevention saves lives and cuts long-term costs. Recent research has shown that each dollar invested in an evidence-based prevention program can reduce costs related to substance use disorders by an average of $18."
Office of National Drug Control Policy: http://www.whitehousedrugpolicy.gov