Chronic pain is medically defined as pain that has lasted 6 months or longer. This constant or intermittent pain has often outlived its purpose, as it does not help the body to prevent injury. It is often more difficult to treat than acute pain. Expert physician care is generally necessary to treat any pain that has become chronic. When opioids are used for prolonged periods drug tolerance, chemical dependency and even psychological addiction may occur. While drug tolerance and chemical dependency are common among opioid users, psychological addiction is rare.

Causes

Chronic pain is essentially caused by the bombardment of the central nervous system (CNS) with nociceptive impulses, which causes changes in the neural response. The pain subsequently provokes changes in the behaviour of the patient, and the development of fear-avoidance strategies. As a result, the patient may also become physically atrophied and deconditioned. However, it is important to remember that chronic pain is multifactorial, involving psychological, physical and social factors.