Chronic pain is a major public health problem.
For example, data from studies of health care needs indicate that pain may be the most significant of the neurobiological disease states in terms of economic and social impact in the United States. Therapeutic options for treatment of pain, especially chronic and abnormal pain states, are inadequate. Many patients with pain from a variety of causes continue to suffer despite attempts at pain therapy. Chronic, abnormal pain states affect almost one-third of all Americans. The lack of effective clinical treatments results in a national loss of productivity, personal and family suffering and other important problems.