Manuela Callari
For too long, people living with chronic pain have been stigmatised for not coping with the negative emotions associated with their condition. But researchers at the University of New South Wales and the NeuRA Institute have found a reason to explain why people with chronic pain might struggle to keep their feelings in check.
“There’s an actual pathological change going on,” says senior author of the study Associate Professor Sylvia Gustin, a neuroscientist and psychologist at UNSW and NeuRA.
The NeuRA scientists have noticed that persisting pain affects the way our brain processes emotions, finding that tendencies to feel down is the result of disruptions to the way brain cells communicate.
In the medial prefrontal cortex – the part of the brain right behind our foreheads – chemical “messengers” called neurotransmitters help communicate and balance messages between brain cells. While some, called excitatory neurotransmitters, amplify signals, others, inhibitive neurotransmitters, weaken them.
Persisting pain affects the way our brain processes emotions – the tendency to feel down is the result of disruptions to the way brain cells communicate.
In their latest study, Gustin and her colleagues have discovered that persisting pain is associated with a decrease in GABA, which is an inhibitive neurotransmitter in the medial prefrontal cortex. GABA, or γ-aminobutyric acid, has a crucial role in helping to dial down our emotions.
The researchers used advanced imaging techniques to measure GABA levels in volunteers with and without a history of chronic pain. The results, recently published in the European Journal of Pain, show that volunteers with persisting pain had significantly lower levels of GABA than the control group, regardless of their type of pain.
“A decrease in GABA means that the brain cells can no longer communicate to each other properly,” says Gustin. “When there’s a decrease in this neurotransmitter, our actions, emotions and thoughts get amplified.”
While a correlation between GABA levels and chronic pain had previously been observed in mice, this is the first time the link is established in humans.
In a previous study, Gustin had observed disruption to levels of another neurotransmitter in people with chronic pain. Levels of glutamate – the main excitatory neurotransmitter – are also lower than average in people with persisting pain. Low glutamate levels are linked to increased feelings of fear, worry and negative thinking.
“It’s important to remember it’s not you – there’s actually something physically happening to your brain.”
“Together, our studies show there’s really a disruption in how the brain cells are talking to each other,” she says. “As a result of this disruption, a person’s ability to feel positive emotions, such as happiness, motivation and confidence, may be taken away, and they can’t easily be restored.”
The mechanism behind these neurological changes through chronic pain is still unclear. The only way to find out would be by scanning participants’ brains before andafter they develop chronic pain – an impractical and costly experiment.
Gustin has hypothesised that the phenomenon is stress-related. At the onset of chronic pain, a lot of stress can often come into people’s lives. “Stress can be very toxic and can trigger changes in neurotransmitter levels or brain function.”
Gustin hopes the findings are encouraging for people with chronic pain experiencing mental health issues. “It’s important to remember it’s not you – there’s actually something physically happening to your brain.”
More than three million people live with chronic pain in Australia, with almost half of them also experiencing significant anxiety and depression disorders.
Medication is often used to help treat chronic pain, but no drugs directly target the GABA and glutamate content in the medial prefrontal cortex. “Unfortunately, pain medications are targeting the entire central nervous system, causing severe side-effects,” says Gustin. But she is confident that her research will provide grounds for developing new, targeted pharmaceutical and non-pharmaceutical treatments.
The first step for people with chronic pain is to recognise those negative emotions.
She and her team are focusing on the non-pharmaceutical. They have developed an online emotional recovery program that aims at reversing this neurotransmitter disruption. The program involves six skills training sessions that are based on dialectical behavioural therapy. The goal is to teach participants the skills needed to mitigate emotions as they arise.
Nell Norman-Nott, one of the emotion recovery trainers at NeuRA, says the first step for people with chronic pain is to recognise those negative emotions.
“Some people can become very good at suppressing emotions,” she says. “The upshot is that they can come back bigger and stronger.”
“By recognising your emotions, being able to name and label them, it helps you to start regulating them.”
Norman-Nott says that before the training, many participants report experiencing flare-ups when a stressful or frustrating event happens in their life. However, after the training, most of them can use the crisis management skills they have learned to cope with negative feelings and avoid flare-ups.
The NeuRA team welcomes people interested in learning more about the program to get in touch at neurorecoveryresearch@unsw.edu.au.