​How Chronic Pain Changes the Brain

September is Pain Awareness Month

Paula* started feeling pain in her shoulder late last year. It started as an ache, but it wasn’t long until routine things like waving to a friend or putting on a sports bra were too painful to do.

She started having problems sleeping and paying attention at work because of the pain.

Paula was eventually diagnosed with a shoulder tear and said some days are worse than others — but the pain is always there. “I don’t remember what it’s like not to have the pain,” she said.

Paula is not alone: About 1 in 5 people living in the U.S. have experienced chronic pain. Research shows women and people assigned female at birth are more likely to have chronic pain than men, and women of color are less likely to be treated for pain compared to white people.

Living with chronic pain can affect all aspects of life and even change the way your brain works.

What is chronic pain?

By definition, chronic pain is pain that lasts for more than three months. It can be constant — like Paula’s — or it can come and go.

There are many causes of chronic pain, including a past illness or injury that’s recovered from but the pain stays. Health conditions like rheumatoid arthritis, osteoarthritis, chronic migraine disease and temporomandibular disorders can be a cause of chronic pain. And some people have chronic pain for unknown reasons without any injuries or past illness.

Regardless of the cause, a growing body of research is showing how chronic pain affects the brain.

Read: After 14 Years of Chronic Pain, I’m Finally Embracing Pain Management >>

How chronic pain changes the brain

“Studies have shown that chronic pain can actually decrease gray matter in the brain,” said Puja Shah, M.D., an interventional pain management specialist and member of HealthyWomen’s Women's Health Advisory Council.

Gray matter is the tissue in your brain and spinal cord that helps with important things such as learning, memory, emotions and movement — pretty much everything you need to perform everyday activities. So, a decrease in gray matter can lead to problems in related areas.

For example, one study found chronic pain led to a reduction in size and activity in the hippocampus — the part of your brain that is responsible for short- and long- term memory among other other things. Other research shows that chronic pain has a negative effect on the regions responsible for emotions and motivation. These changes can lead to personality shifts and feelings of anger and anxiety.

Chronic pain has also been linked to various health conditions dealing with the brain including:

• Addiction
• Alzheimer’s disease
• Depression
• Insomnia

Chronic pain can also alter areas in the brain responsible for cognitive function. “These alterations can cause difficulties with focus, learning and problem-solving, even when the pain is not at the forefront of that person’s experience,” said Jane Wigginton, M.D., medical science research director at the Center for Brain Health.

The presence of constant pain also has a big impact on mental and emotional health. “The emotional centers of the brain, like the amygdala and regions involved in emotional regulation, become more reactive under the constant pressure of pain,” Wiggington said. “This can lead to increased anxiety, frustration and feelings of hopelessness.”

Over time, chronic pain can reduce the brain's ability to experience joy and pleasure, which can add to emotional problems.

Chronic pain and depression

The emotional wear paired with constant pain may make people living with chronic pain more vulnerable to mental health conditions like depression.

Chronic pain shares neural pathways with mood and reward systems in the brain, which explains why chronic pain has been linked to depression and substance use disorders.

“Persistent pain can disrupt the balance of neurotransmitters like serotonin and dopamine, which regulate mood, pleasure and motivation. This disruption can lead to feelings of depression, anxiety and a diminished sense of reward, making it more challenging for individuals to find relief or experience joy,” she said.

The fact that chronic pain is an invisible illness can also lend to feelings of loneliness, which can lead to social isolation and depression. Studies show that people living with chronic pain are more vulnerable to social isolation and, in turn, isolation can make symptoms of chronic pain worse.

Stress is another factor that can make chronic pain worse because it accelerates changes in brain function. Basically, the body releases cortisol, also called the “flight or flight” hormone, which can decrease the brain’s ability to manage emotions and pain. “Chronic stress may also make the brain more sensitive to pain signals, increasing both discomfort and emotional strain,” Wigginton said.

Shah said recent studies and advancements in medical imaging have helped put the spotlight on how chronic pain changes the brain. “It also shows that pain in and of itself is a true mind/body disease,” Shah said. “It’s validation that suffering is causing long-term damage.”

Read: Tech Solutions for Chronic Pain >>

Chronic pain in women

There’s still a lot about chronic pain that we don’t know. But, we do know that women and men experience pain differently and women are more sensitive to pain overall compared to men. Wigginton said this is due, in part, to hormonal fluctuations. “These fluctuations, particularly during menstruation, pregnancy and menopause, can heighten pain sensitivity and alter the way the brain processes pain signals,” she said.

Shah noted that chronic pain isn’t necessarily about tolerance — chronic pain is a complex interconnected disease that feels different depending on the person. And there can be stigma surrounding chronic pain that can keep people from getting the help they need.

Read: Breaking Barriers to Pain Treatment >>

“Women are less likely to speak up when experiencing a chronic pain condition,” Shah said. “This is for many reasons, including cultural norms, difficulty in finding the space and time for women to prioritize their self-care and bias in the medical community regarding treatment for men versus women.”

Historically, women have been left out of clinical trials and the conversation surrounding chronic pain despite being more likely to be diagnosed with pain conditions compared to men.

The issue of chronic pain and treatment for chronic pain is personal to Shah. She had migraine attacks for years but said a mind/body approach including medication and aligning her posture has helped her have better control over her migraine attacks.

The first step, she said, is awareness. “Too often we diminish things to be normal when they’re not.”

Both Shah and Wigginton said brain-healthy habits such as reducing stress, practicing mindfulness and getting enough sleep and physical activity can help with the symptoms of chronic pain.

“It's essential for women to know that they are not powerless in this process,” Wigginton said. “There are multiple pathways to improving brain health and well-being, and by understanding and addressing the brain's role in pain, women can feel empowered to thrive in their lives, despite the challenges chronic pain may bring.”