- Anti-inflammatory medications, ranging from aspirin to nonsteroidal drugs and steroids, act on the nerves that detect pain on the periphery of the body. They generally succeed best with problems like osteoarthritis, where bones wear on each other, or an inflamed wound.
- Anti-seizure drugs may correct the spontaneous misfiring of sensory neurons, which can occur with herniated disks, headaches, or chronic regional pain syndrome, also known as CRPS.
- Antidepressants build up the brain's ability to block descending pain signals and work for many conditions involving nerve injury. (They do not require the person to be emotionally depressed.)
- Opioids and some synthetic narcotics tone down ascending sensations of pain and amplify descending inhibitory signals. Doctors use opioids with care. They can be addictive, since they activate the brain's ventral tegmental area, which is related to the limbic system and rewards people during pleasurable activities like eating or having sex. Opioids are most appropriate for acute pain, but may be used carefully with chronic pain, Trescot says.
A homeostatic process. A form of medical acupuncture being practiced increasingly in the United States blends Chinese approaches, developed over 1,500 years, with a Western understanding of neurophysiology, says Gary Kaplan of McLean, Va., who is board-certified in medical acupuncture, family medicine, and pain medicine. Acupuncturists place fiber-thin needles at varying depths, often between ¼ and 2 inches, at carefully mapped points on the body, depending on the diagnosis. The needles arouse the nerves and release endorphins, which activate opioid receptors in the spinal column and brain, relieving the pain. Acupuncture stimulates the release of neurotransmitters, and the increase in their production seems to be progressive with long-term treatment. "It's a homeostatic process," says Kaplan. The goal is to bring the body back to its normal ability to self-heal.
Mind over matter. Research has shown that people can activate their descending pathways to block pain by distracting themselves with work, family, or hobbies they enjoy. Studies also have found that clinical hypnosis can help patients learn how to alter activity in specific areas of the brain, says Mark Jensen, a clinical psychologist and professor at the University of Washington Department of Rehabilitation Medicine. For example, hypnotic suggestions can reduce patient discomfort by decreasing activity in the anterior cingulate cortex, the area of the brain that processes the emotional response to pain. Such suggestions can also target the sensory cortex, which determines components of pain such as its intensity and what it feels like. A variety of disciplines are examining the use of hypnosis, which has been employed in dental procedures and studied as an aid to reduce pain in women with breast cancer.
Stanford's Mackey is currently exploring how to teach patients to manage their own pain. In 2006 he used functional magnetic resonance imaging scans to successfully train patients to consciously increase or decrease activity in the regions of their brains that processed the pain they experienced. While the research continues, Mackey hopes the approach will eventually be refined sufficiently to allow for its widespread use.