Chronic Nerve Pain Can Impact Mood and Motivation

/ Thomas Cohn, MD

Chronic Pain BrainChronic nerve pain doesn’t just make it painful to go through your daily routine, it may actually make it psychologically harder for your brain to get motivated to complete certain tasks, according to California researchers.

Researchers at UC-Irving and UCLA say their findings suggest that brain inflammation caused by chronic nerve pain can have significant psychological effects. In a lab study, researchers uncovered that rodents with brain inflammation exhibited “accelerated growth and activation” of immune cells known as microglia. These microglia cells cause chemical signals that restrict the release of dopamine, a chemical that helps control our brain’s reward and pleasure centers.

New Approaches To Chronic Pain Care

What’s more, the researchers may have uncovered new evidence in the battle to control and conquer chronic pain. Researchers found that certain opioids designed to spur the release of morphine may actually be ineffective in certain cases. One such case occurred with these rats. In rodents with brain inflammation, these opioids did not stimulate dopamine release as designed.

Instead, when the same rodents were treated with an opioid designed to inhibit the release of the microglial cells, dopamine levels returned to normal.

“For over 20 years, scientists have been trying to unlock the mechanisms at work that connect opioid use, pain relief, depression and addiction,” said Catherine Cahill, an associate professor of anesthesiology & perioperative care at UCI. “Our findings represent a paradigm shift which has broad implications that are not restricted to the problem of pain and may translate to other disorders.”

Cahill and her team hope to recreate the study in humans in order to combat mood swings, depressive attitudes and behavioral disorders.

“We have a drug compound that has the potential to normalize reward-like behavior,” she said, “and subsequent clinical research could then employ imaging studies to identify how the same disruption in reward circuity found in rodents occurs in chronic pain patients.”