Brain inflammation links chronic pain with depression
For the first time, scientists have discovered that brain inflammation caused by chronic nerve pain can affect signaling in the regions of the brain associated with mood and motivation. This discovery suggests there is a mechanism that connects chronic pain with symptoms of depression and anxiety that many patients experience.
The findings of the study, published in the Journal of Neuroscience, could lead to new methods of treatment for chronic pain, the most common form of enduring illness for people aged below 60 in the US.
Researchers from the University of California-Irvine(UCI) and the University of California-Los Angeles (UCLA) made their discovery after examining the growth of immune cells in the brains of mice and rats with chronic pain.
According to the American Academy of Pain Medicine (AAPM), pain affects more people in the US than diabetes, heart disease and cancer combined, with an estimated 100 million Americans experiencing chronic pain.
Chronic pain is also strongly associated with the development of other conditions such as depression, anxiety and substance abuse, with these three seen in more than half of patients with chronic pain. Among illness-related causes of suicide in the US, chronic pain is second only to bipolar disorder.
Catherine Cahill, associate professor of anesthesiology and perioperative care at UCI, and colleagues discovered that inflammation in the brain caused by chronic pain increased the rate at which specific immune cells grew and became activated.
These cells, known as microglia, set off chemical signals in the brain that inhibited the release of dopamine, crucial to the regulation of areas of the brain associated with reward and pleasure.
Dopamine is one of the most important neurotransmitters, associated not only with the reward system of the brain but with cognitive and motor functions. Some studies have also linked disruption to the dopamine response with psychosis and schizophrenia.
MNT
