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 thatinflammation 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 andschizophrenia.