Chronic pain

Chronic pain is pain that persists or recurs for longer than 3 months. It is also described as burning, electrical, throbbing, or nauseating pain. This type of pain contrasts with acute pain, which is associated with a specific cause, typically resolves when the cause is treated, and decreases over time. Chronic pain can last for years. Persistent pain often serves no apparent useful purpose. The most common types of chronic pain include back pain, severe headache, migraine, and facial pain. Chronic pain can lead to severe psychological and physical effects that may persist for a lifetime. Physical complications can include damage to brain neurons (grey matter loss), insomnia and sleep deprivation, metabolic disorders, chronic stress, obesity, and heart attack. Mental health consequences may include depression and neurocognitive disorders. A wide range of treatments are used for chronic pain; drug therapy including opioid and non-opioid drugs, cognitive behavioral therapy and physical therapy are the most common interventions. Medications such as aspirin and ibuprofen are used for mild pain whereas morphine and codeine are prescribed for severe pain. Non-pharmacological treatments, such as behavioral therapy and physiotherapy, are often used as complementary approaches due to their limited effectiveness when used alone. There is currently no definitive cure for chronic pain, and research continues into new management and therapeutic options, such as nerve blocks and radiation therapy. An average of 8% to 11.2% of people in different countries experience severe chronic pain, with higher incidence in industrialized countries. Epidemiological studies show prevalence in countries varying from 8% to 55.2% (for example 30-40% in the US and 10-20% in Iran and Canada). Chronic pain affects more people than diabetes, cancer, and heart disease. According to the estimates of the American Medical Association, the costs related to chronic pain in the US are about US$560-635b.