"Dealing with psychology is part of dealing with chronic pain. It doesn't mean you're crazy if you have chronic pain," said Dr. Joel Saper, director of the Michigan Head Pain and Neurological Institute in Ann Arbor. "It's about a bilateral dynamic. Your emotions can make you vulnerable, and pain can affect your emotions."
He pointed to work by Dr. Irene Tracey of Oxford University, who used brain scans to discover that people's pain intensifies when they think about their headaches. Tracey's work has confirmed that fear and anxiety make pain worse, while pleasurable or distracting activities such as listening to music or watching a movie can actually reduce the amount of pain a person feels.
Catherine Bushnell, a researcher at McGill University's Center for Research on Pain in Montreal, using brain imaging, has also shown that being distracted has a real effect in decreasing the intensity of pain signals in the brain. She and her colleague, Chantal Villemure, subjected volunteers to slightly painful pulses of heat and, in other tests, they had them listen to different tones at the same time.
The subjects reported that their perception of pain diminished when they were listening to the tones -- and brain scans revealed that pain signals in their brain actually lessened as they listened to the tones.
"This means that things like having family around constantly asking how you feel can actually draw more attention to your pain and enhance it," Bushnell said.
Emotion can also enhance or decrease people's perception of pain, her studies show. Bushnell and Villemure demonstrated that subjecting people to pleasant and unpleasant odors influences how much they are bothered by pain. Pleasant odors eased the sensation of pain while unpleasant smells made the pain feel worse. Bushnell's and Villemure's work is published in a recent issue of the journal Pain.
This may be because one part of the brain, the anterior cingulate cortex, seems to be involved in both the processing of emotions and of pain, Mackey said.
The question, he said, is whether the ACC acts as a "gatekeeper," sorting through different stimulae and letting more of one through while limiting others, or acts more as an amplifier or soundboard, turning up the volume on one stimulus -- perhaps something pleasurable or interesting -- and turning down the volume on another stimulus that is less positive.
"We're trying to tease it apart," Mackey said. "I honestly don't think we have the answer to that question."
And when it comes to putting all this into practice to help patients, doctors and psychiatrists admit they are still learning.
"One of the problems with this field is that we are working with a lot of speculation, because there is not a lot of research on the link between emotion and pain. But common sense tells us there is a link," said Dr. Janina Fisher, a psychologist who practices at the Center for Integrative Healing in Watertown, Mass., and teaches at The Trauma Center in Brookline, Mass., and Harvard Medical School.
She said for too long there has been a split between the medical health and mental health professions, training physicians to work solely on the body and therapists to work only on the mind.
"Most health professionals do not make the mind-body link," she said.