An overview of chronic pain.

Pain is the most common symptom for which patients seek medical advice and treatment, and chronic pain takes a heavy toll in patient suffering and disability, reduced quality of life, and economic costs. Despite the interest in pain management in the last half century, the pathways of pain transmission and the optimal methods of pain management are not fully understood. The authors review selected areas of knowledge about chronic pain and its management, including historical views, the assessment of pain, economic factors and costs, and treatment approaches.