Chronic pain is defined as pain that has lasted longer than three to six months, though some theorists and researchers have placed the transition from acute to chronic pain at 12 months. Others apply acute to pain that lasts less than 30 days, chronic to pain of more than six months duration, and subacute to pain that lasts from one to six months. A popular alternative definition of chronic pain, involving no arbitrarily fixed duration, is "pain that extends beyond the expected period of healing".
- Chronic Pain and the Therapeutic Benefits of Medical Cannabis by Dr. Malik Burnett (June 13, 2014), Medical Jane
- Chronic pain at Wikipedia. Retrieved September 30, 2014.