Brain scans suggest they emerge from distinct areas
THURSDAY, May 5 (HealthDay News) -- Recurrent pain and depression often go hand-in-hand, and doctors have long puzzled over whether treating one will get rid of the other. But a new study of brain patterns on MRI tests suggests the two problems should be treated separately, even when they co-exist.
The study included 42 healthy people and 53 individuals with fibroymyalgia, a condition characterized by intense widespread pain and tenderness to touch, often accompanied by depression.
Researchers at Georgetown University, in Washington, D.C., wanted to determine whether higher levels of depression symptoms are associated with increased sensitivity to pressure-induced pain. They also sought to identify specific brain regions involved in processing acute pain, chronic pain and symptoms of depression.
Both the fibromyalgia patients and healthy people underwent pressure-pain sensitivity testing, which involved application of pressure to the thumbnail. Before, during and after the pressure-pain testing, magnetic resonance imaging (MRI) was used to observe the brain's response to the stimulus.
During the study, the fibromyalgia patients were also asked to stop taking antidepressant medications for four weeks before the start of the study, and to cease using painkillers three days before the study.
MRI results showed that, compared with the healthy people, fibromyalgia patients required far less applied pressure to activate neurons associated with acute pain located in the brain's sensory domain. The heightened sensitivity to pain was seen among fibromyalgia patients whether or not they'd been diagnosed with major depression or had reported any symptoms of depression.
The study also found only a weak correlation between the emotion-oriented and pain-sensory brain regions, suggesting the two were not interacting.
"Much has been made of the overlap and similarities between pain and symptoms of depression, but these and other data suggest it is also important to identify pain-processing mechanisms that are independent of mood," study lead author Dr. Thorsten Giesecke said in a prepared statement.
"The notion that sensory and [emotional] aspects of pain may be independently processed is not just of theoretical interest," he said, since better evaluation of these separate aspects of brain response "is likely to improve diagnosis, choice of treatment, and treatment efficacy."
The findings were reported in the May issue of Arthritis & Rheumatism.
SOURCE: John Wiley & Sons, Inc., news release, May 5, 2005
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