"Chronic pain has a distinct pathology, causing changes throughout the nervous system that often worsen over time. It has significant psychological and cognitive correlates and can constitute a serious, separate disease entity." (Relieving Pain in America, Report by US Institute of Medicine, 2011).
Chronic pain is defined as any pain lasting more than 12 weeks despite treatment and coping strategies implemented by the individual. The onset of chronic pain may arise from an initial injury, an ongoing illness, or there may not be any identified cause. Fatigue, sleep disturbance, decreased appetite, and mood changes, often accompany chronic pain. Chronic pain may limit a person’s movements, which can reduce flexibility, strength, and stamina. Difficulty in carrying out important and enjoyable activities can lead to disability and despair and impact negatively on family and social relationships.