Monday, May 09, 2005

Research: Treating depression may not necessarily alleviate chronic pain

Clinical Psychiatry News: "Researchers recommend treating pain and depression independently after finding that the sensory regions of the brain associated with pain are only weakly correlated with the emotional brain regions linked to depression.

Reporting in the journal Arthritis and Rheumatism, Thorsten Giesecke (University of Michigan, Ann Arbor, USA) and colleagues say that their findings indicate that treating an individual's depression by prescribing an antidepressant medication that has no analgesic properties 'will not necessarily have an impact on the sensory dimension of pain...'

..the researchers interviewed 53 patients with fibromyalgia, a condition characterized by widespread pain and tenderness to touch, along with 42 healthy individuals, about the severity of their chronic pain and depressive symptoms.

In addition, both the fibromyalgia patients and controls participated in a pressure-pain sensitivity test, during which pressure was applied to the thumbnail.... significantly less pressure was needed to cause acute pain in the patients with fibromyalgia than was needed for controls. However, the investigators found that this heightened sensitivity to pain was unaffected by the extent of depressive symptoms or the presence of comorbid major depressive disorder.

Magnetic resonance imaging scans carried out before, during, and after the pressure-sensitivity tests showed that, while symptoms of depression and comorbid major depressive disorder were associated with the magnitude of pain-evoked neuronal activations in brain regions associated with emotional pain processing, they were not linked to the sensory aspects of pain processing, such as where the pain is and its intensity.

"It appears as though there are different and easily distinguished sensory and affective elements to each individual's pain experience," says the team. "There are strong data suggesting that these elements are somewhat independent of one another and respond differentially to both pharmacologic and nonpharmacologic interventions." "

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