What is chronic pain?

Chronic pain¹ refers to persistent, long-lasting pain. The pain may last from weeks to months (but typically lasts for at least six months).

Chronic pain often affects older adults. The condition occurs when the body’s nervous system continues to fire pain signals for a long period of time. While it may have originally been caused by an injury or illness, the pain persists even after the underlying cause has healed. In some cases, chronic pain occurs without any injury or apparent damage to the body.

Some of the most common forms of chronic pain are lower back pain, chronic daily headache, arthritis pain, cancer pain, neurogenic pain (pain caused by damage to the peripheral nerves or the central nervous system), and psychogenic pain (pain that can’t be attributed to a prior injury or disease or any apparent damage to the central nervous system).

Chronic pain is linked to a number of health conditions and often significantly lowers a patient’s quality of life. They may struggle to move around normally and may not be able to attend school or work consistently. Constant pain can also affect appetite and mental health, causing anxiety, depression, anger, and even fear of injury or re-injury.

Chronic pain is often idiosyncratic, meaning it looks different in each patient. Chronic pain can come and go, its symptoms—including their severity and duration—can vary between individuals. Generally, it can cause sensations like achiness, burning, tingling, and pins and needles. The pain can occur in different parts of the body simultaneously, or different areas can hurt at different times.

Treatment for chronic pain is often aimed at reducing the pain and discomfort that the patient experiences. In some cases, patients with chronic pain choose to work with pain specialists or therapists to learn how to alleviate their symptoms or more effectively cope with their pain.

How common is chronic pain?

Approximately 1 in 5 people², or 20%, are affected by chronic pain worldwide. At least 116 million adults³ live with chronic pain in the United States alone.

The likelihood of being affected by chronic pain increases with age. This is, in part, due to the fact that older people are more likely to develop the conditions associated with chronic pain. Researchers also propose that because nerve function can deteriorate with age, the pain nerves in older adults are more likely to malfunction and continue firing, leading to chronic pain.

Chronic pain syndrome

Chronic pain syndrome⁴ is the official name of the diagnosis given to patients with chronic pain and its associated symptoms.

In most cases, patients with chronic pain syndrome can pinpoint the cause of their chronic pain, whether it is a disease, an injury that has since healed, or a chronic condition, such as fibromyalgia.

A diagnosis of chronic pain syndrome takes into account a multitude of factors, including the severity of a patient’s pain, the effects of the pain, and how those effects negatively influence the patient’s life.

Acute vs. chronic pain

The terms “acute” and “chronic” are used to describe a wide array of conditions. Generally speaking, acute conditions are short-lasting with recent onset, while chronic conditions are persistent and long-lasting, developing over time.

In accordance with these terms, acute pain⁵ comes on suddenly and is caused by a specific event or illness, such as an injury or infection. Even if the exact cause of acute pain is evident right away, imaging tests or other types of tests can sometimes reveal what is causing the pain.

Although there are many ways that patients describe acute pain, it is usually described as a sharp pain. It tends to last for less than 6 months. As the underlying condition or injury that caused the acute pain heals or goes away, so does the pain itself.

Chronic pain, on the other hand, is lingering. It may begin as acute pain or be caused by an underlying condition, or it may show up on its own, seemingly out of the blue. Either way, chronic pain lasts for more than six months. Because its cause may be unidentified, chronic pain is often harder to treat than acute pain.

Causes of chronic pain

In some cases, chronic pain occurs⁶ as the result of an underlying chronic condition, such as arthritis, that continually causes pain. Because many of these conditions cannot be healed (or take longer than six months to heal), the pain they cause is considered to be chronic.

Some conditions that can cause chronic pain include:

• Arthritis
• Headaches (especially migraines)
• Back injuries
• Nerve damage, injury, or disease
• Fibromyalgia
• Cancer
• Extensive surgery, like hip replacement
• Diabetic neuropathy
• Painful scars
• Trigeminal neuralgia (affects the trigeminal nerve, which carries sensations from the face to the brain)

Chronic pain can also occur when the body’s nerve cells⁷ don’t stop firing. They may have originally begun firing because of an injury, illness, surgery, or other acute cause but malfunctioned and continued to fire after the original condition had healed.

Researchers are not yet sure why these nerves don’t stop firing. While they also don’t know how to turn these nerves off, medical practitioners eventually hope to be able to stop these responses when they occur so that fewer people are affected by chronic pain.

Risk factors for chronic pain

While researchers are not sure why some people develop chronic pain while others do not, there are a few factors⁸ that seem to increase the risk for long-term pain. These include:

• Obesity: Studies show that people with body mass indices (BMIs) that indicate obesity (30 or higher) are more likely to struggle with chronic pain. In those with certain conditions that contribute to chronic pain, such as arthritis, weight loss can significantly lower pain levels.
• Genetics: Certain genes control the body’s pain pathways. While there is no one gene that causes chronic pain, environmental factors seem to interact with genetics to cause the condition. While chronic pain conditions have also been shown to run in families, more research is needed to determine exactly why some family members develop these conditions and others do not.
• Disrupted sleep: People who struggle to fall asleep or stay asleep are more likely to develop chronic pain. Addressing sleep issues in people who are in pain also lessens a person's chance of falling into depression, which correlates with even higher pain levels.
• Nutrition: People who don’t get enough of certain substances, like omega-3 fatty acids, may be at an increased risk for chronic pain. Supplementing your diet with omega-3, which can be found in fish or over-the-counter supplements, may help improve certain types of pain.
• Old age: People who are older are more likely to develop the conditions that cause chronic pain, such as arthritis.
• Being female: Women are affected by chronic pain more frequently than men.
• A history of trauma or abuse: Those who have faced abuse or other traumatic experiences are more likely to suffer from chronic pain later in life than those who have not.
• Smoking: Heavy smokers tend to describe experiencing more pain than those who do not smoke. However, there is insufficient evidence to draw a definite connection between smoking and chronic pain. Studies have suggested that heavy smoking and depression may be associated with chronic pain.
• Mental health conditions: Both anxiety and depression have been associated with chronic pain. Causation here may lead both ways: having a mental health condition may predispose an individual to chronic pain, while chronic pain can also lead to these conditions.

Chronic pain symptoms

Chronic pain is characterized⁹ by mild to extreme pain that does not go away or that returns often and regularly (during periods called flares, or flare-ups). This pain does not dissipate as expected and may last for months after its original cause has resolved.

Patients may use many different terms¹⁰ to describe their pain, including:

• Aches
• Soreness
• Stinging
• Squeezing
• Stabbing
• Throbbing
• Burning
• Shooting

If the affected, painful area is a joint, it may also be stiff or tight, even if there is not an obvious cause for these symptoms.

If you experience any of the signs or symptoms of chronic pain, talk to a healthcare provider. They will be able to assess your symptoms in order to provide the right diagnosis and treatment.

Complications from chronic pain

Chronic pain is comorbid (coexisting) with a number of health conditions. In addition, it can lead to the following complications¹¹:

• Anxiety
• Fear of re-injury
• Trauma
• Opioid dependence
• Unemployment
• Financial stress
• Insomnia
• Extreme fatigue
• Stress-induced health issues
• Poor concentration and short-term memory
• Social isolation
• Decreased quality of life

With effective treatment, many patients with chronic pain avoid all, or at least the worst, of these complications. Seeking out the treatment that works for you can take a lot of energy and time, but it is worthwhile when symptoms and complications begin to improve.

Chronic pain and depression

Chronic pain can lead to depression¹². However, depression can also cause and exacerbate pain. Because of this, many chronic pain patients find themselves in a vicious cycle with depression and their symptoms: they are in pain and become depressed as a result of decreased quality of life. That depression, in turn, may worsen their pain, further contributing to depression.

Chronic pain can cause depression in a number of ways. Dealing with pain constantly over a long period of time takes a lot of mental energy and can leave a person tired and frustrated, which can lead to depression. Additionally, pain can keep people from sleeping well and a lack of sleep is also tied to depression.

Pain can also prevent people from participating in activities that make them happy (and which release endorphins in the brain). They may not be able to work, socialize, or exercise regularly. All of these limitations can contribute to depression.

Many people with chronic pain find it useful to treat their depression concurrently with their pain. This can help break the pain/depression cycle and lead to an improvement in both conditions.