ABSTRACT
Alcohol and drug abuse are pervasive public health problems that affect millions of people at an estimated annual cost to society of nearly $250 billion in the United States alone [1,2]. The potential relationship between delta opioid systems and substance abuse is of practical interest for at least two reasons. First, as reviewed in this volume, novel and selective delta opioid ligands are being developed and evaluated for a wide range of clinical applications, and the abuse liability of these compounds may influence the conditions under which they can be made available for clinical use. In one historically famous example, heroin was originally developed and marketed at the end of the 19th century as an alternative to morphine for the treatment of cough. Despite its effectiveness as an antitussant, heroin’s abuse potential quickly became apparent, and because of its widespread abuse, clinical use of heroin was ultimately prohibited [3]. Preclinical procedures are now available to assess the abuse liability of novel drugs before they are approved for clinical use, and data from these procedures are routinely used by the U.S. Food and Drug Administration to determine the degree of control that will be exercised over the distribution of new drugs.
