The American Chronic Pain Association (ACPA) defines chronic pain as “ongoing or recurrent pain, lasting beyond the usual course of acute illness or injury or more than 3 to 6 months, and which adversely affects the individual’s well-being.” In other words, chronic pain is pain that continues after it should have stopped.  The study of pain has a long history: the early Romans and Greeks forwarded the idea that the brain played a role in producing the perception of pain; physicians/scientists in the 19^th century discovered that opiates could relieve pain, and Felix Hoffman, a chemist, developed aspirin from a substance found in willow bark; and current research in chronic pain has focused on its effects on emotion and cognitive abilities.

According to the National Institutes of Health (NIH), pain affects more Americans than diabetes, heart disease, and cancer combined; and is the leading cause of disability. Chronic pain is the most common cause of long-term disability. It is also cited as the most common reason that Americans access the health care system and is a major contributor to health care costs. Pain can be a chronic condition, and it can be associated with long-term physical and psychiatric disabilities such as depression, post-traumatic stress disorder (PTSD), multiple sclerosis, and traumatic brain injury (TBI). Because pain conditions are so diverse, a variety of research and treatment approaches is needed.

Over the years, researchers have discovered that there are differences in pain perceptions and responses to treatment according to a person’s gender. These discoveries have led to new avenues of research related to the experience and relief of pain. Examples of these discoveries include:

• Medications called kappa-opioids increase pain in men, yet provide good acute pain relief in women.
• Cyclooxygenase-2 (COX-2) is a huge contributor to pain associated with inflammation.
• Pain-related behavioral interventions have shown promise in providing pain relief in conjunction with or in place of drug interventions.

In its over 30 year history, the NIDILRR community has delved into researching chronic pain. Currently, there several NIDILRR-funded projects that are researching chronic pain in association with disabilities. Some of that research can be found at the Model Systems Knowledge Translation Center and includes a factsheet on pain and spinal cord injury (SCI) , a hot topic module on managing pain after SCI, a factsheet on headaches after TBI, and managing pain after a burn injury. We ran searches in REHABDATA to find the articles in the NARIC collection on chronic pain and on chronic pain and disability.

We look forward to seeing what NIDILRR and the broader research community discover about chronic pain and what interventions they create to help people with chronic pain.