Additionally, a conceptual division exists between commonly abused drugs obtained on the street or illicit market, and those intended for use as prescription medication. When considering the phenomenon of substance abuse, the distinctions are ultimately quite arbitrary – use of all of the following substances can result in a similar pattern of dependency or addiction. Indeed, all are major contributors to the clinical landscape of substance use disorders. More promisingly, however, substance abuse treatment efforts continue to make strides in helping the millions of Americans struggling with them.