Pain that persists for longer than 6 months is referred to as chronic pain (Keefe, 1982). Unrelieved chronic pain can cause considerable suffering, physical limitations, and emotional distress (Turk, 1996). Further, chronic pain is one of the most common reasons for seeking medical care but often persists despite treatment with analgesics and physical modalities. For example, epidemiologic studies indicate that approximately 11% to 45% of individuals in the United States experience chronic back pain (LeResche & Von Korff, 1999), 75% of patients with advanced cancer suffer persistent pain (Bonica, 1990), and chronic pain is the most common reason for the use of complementary and alternative therapies
