Chronic pain is defined in different ways, but most often it is considered to be pain that lasts between three and six months beyond the normal period it usually takes to heal after an injury or illness has been resolved. People with chronic pain often experience insomnia, depression, anxiety, and irritability, which in turn can make pain worse. There are different types of pain. Pain may be diagnosed according to its original cause or as a syndrome — a collection of symptoms that forms a specific pattern.

What Causes Chronic Pain?

Chronic pain can linger after an injury, a surgery, or an outbreak of shingles (herpes zoster). Chronic illnesses such as rheumatoid arthritis, endometriosis, or fibromyalgia feature pain as a prominent symptom. Chronic pain can be caused by cancer, migraines, or nerve damage. In some cases, the pain does not have a clear cause. Regardless of the origin of the pain, there are genetic and environmental risk factors that make someone more or less likely to develop chronic pain. Read more about potential causes of chronic pain.

The History of Chronic Pain

For most of human history, pain without obvious cause was referred to as rheumatism — a vague term for inflammation in muscles and joints. At times, people who looked well but reported pain and fatigue were labeled mentally ill.

In the 17th century, many European doctors gave opium to relieve pain. In the 19th century, morphine was isolated from opium and became the standard treatment for acute and recurrent pain. In the early 1900s, heroin was created by Bayer as a less-addictive alternative to morphine. In fact, heroin was found to be more addictive than morphine. Doctors understood its addictive nature, but they became increasingly pressured to relieve pain as a mainstay of their job.

Bayer also created Aspirin, which became available over the counter in 1917. Aspirin was highly effective for mild-to-moderate pain, and it is thought that aspirin helped servicemen avoid opiate overuse during World War I. The launch of Aspirin was followed later in the 20th century by other nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin).

The formation of pain as a field of medicine wouldn’t begin until the 1960s. American anesthesiologist John Bonica gathered 300 doctors and researchers together to form the International Association for the Study of Pain and launch the medical journal Pain.

Today doctors are still searching for answers to understand chronic pain and to find nonaddictive treatments. Over the past 25 years, pain research has expanded to study complementary pain relief methods such as acupuncture, counterstimulation techniques such as transcutaneous electrical nerve stimulation (TENS), and behavioral methods such as cognitive behavioral therapy.

How Common is Chronic Pain?

By some estimates, approximately 28 percent of the adult population in the U.S. lives with a form of chronic pain. Chronic pain is thought to affect more people than heart disease, cancer, and diabetes put together. Chronic pain is considered to be the leading cause of long-term disability in the U.S.

Condition Guide

• Causes of Chronic Pain
• Chronic Pain — The Path to Diagnosis
• Symptoms of Chronic Pain
• Treatments for Chronic Pain
• Types of Chronic Pain

FAQs

What are the different types of chronic pain?
Chronic pain may be categorized by its cause, its location, or whether it is related to body or tissue damage. Read more about different types of chronic pain.

How is chronic pain diagnosed?
There is no one conclusive test for diagnosing chronic pain. An evaluation of chronic pain will usually include a thorough personal medical history with many questions about symptoms over time and how pain affects your daily activities. The doctor will assess pain, psychological and social factors, and may perform a neurological exam. Depending on the suspected cause of the chronic pain, the doctor may order blood tests, imaging studies, or nerve conduction tests.

Read more about the process of diagnosing chronic pain.

What are the symptoms of chronic pain?
Pain can be felt in many different ways. For instance, neuropathic pain, bone pain, and visceral (organ) pain are all unique. In sciatica, pain may shoot down the leg and make it difficult to walk, whereas migraine pain may spike in bright light. General symptoms common in those with chronic pain include insomnia, fatigue, depression, and anxiety.

Read more about chronic pain symptoms.

How is chronic pain treated?
Treatment for chronic pain depends on the type and severity of the symptoms. For mild pain, nonsteroidal anti-inflammatory drugs (NSAIDs) such as Advil (Ibuprofen), Naprosyn (Naproxen), and Indocin (Indomethacin) are tried first. If NSAIDs do not adequately control pain, it may be treated with opioids. Antidepressants and muscle relaxants may ease other symptoms. Some types of pain may be treated with surgical procedures or nerve block injections. Some people with chronic pain use medical marijuana or complementary or alternative treatments such as acupuncture.

Read more about treatments for chronic pain.