chronic pain chronic pain chronic pain is classified as pain that lasts longer than three months. in medicine, the distinction between acute and chronic pain is sometimes determined by the amount of time since onset. two commonly used markers are pain that continues at three months and six months since onset, but some theorists and researchers have placed the transition from acute to chronic pain at twelve months. others apply the term acute to pain that lasts less than 30 days, chronic to pain of more than six months duration, and subacute to pain that lasts from one to six months. a popular alternative definition of chronic pain, involving no fixed duration, is "pain that extends beyond the expected period of healing". chronic pain may originate in the body, or in the brain or spinal cord. it is often difficult to treat. epidemiological studies have found that 8–11.2% of people in various countries have chronic widespread pain. various non-opioid medicines are initially recommended to treat chronic pain, depending on whether the pain is due to tissue damage or is neuropathic. psychological treatments including cognitive behavioral therapy and acceptance and commitment therapy may be effective for improving quality of life in those with chronic pain. some people with chronic pain may benefit from opioid treatment while others can be harmed by it. people with non-cancer pain who have not been helped by non-opioid medicines might be recommended to try opioids if there is no history of substance use disorder and no current mental illness. people with chronic pain tend to have higher rates of depression and although the exact connection between the comorbidities is unclear, a 2017 study on neuroplasticity found that "injury sensory pathways of body pains have been shown to share the same brain regions involved in mood management." chronic pain can contribute to decreased physical activity due to fear of making the pain worse. pain intensity, pain control, and resilience to pain can be influenced by different levels and types of social support that a person with chronic pain receives, and are also influenced by the person's socioeconomic status. one approach to predicting a person's experience of chronic pain is the biopsychosocial model, according to which an individual's experience of chronic pain may be affected by a complex mixture of their biology, psychology, and their social environment. classification main article: pain § classification the international association for the study of pain defines chronic pain as pain with no biological value, that persists past normal tissue healing. the dsm-5 recognizes one chronic pain disorder, somatic symptom disorders. the criteria include pain lasting longer than six months. the international classification of disease, eleventh revision (icd-11) suggests seven categories for chronic pain. chronic primary pain: defined by 3 months of persistent pain in one or more regions of the body that is unexplainable by another pain condition. chronic cancer pain: defined as cancer or treatment related visceral (within the internal organs), musculoskeletal, or bony pain. chronic post-traumatic pain: pain lasting 3 months after an injury or surgery, excluding infectious or pre-existing conditions. chronic neuropathic pain: pain caused by damage to the somatosensory nervous system. chronic headache and orofacial pain: pain that originates in the head or face, and occurs for 50% or more days over a 3 months period. chronic visceral pain: pain originating in an internal organ. chronic musculoskeletal pain: pain originating in the bones, muscles, joints or connective tissue. chronic pain may be divided into "nociceptive" (caused by inflamed or damaged tissue activating specialized pain sensors called nociceptors), and "neuropathic" (caused by damage to or malfunction of the nervous system). nociceptive pain can be divided into "superficial" and "deep", and deep pain into "deep somatic" and "visceral". superficial pain is initiated by activation of nociceptors in the skin or superficial tissues. deep somatic pain is initiated by stimulation of nociceptors in ligaments, tendons, bones, blood vessels, fasciae and muscles, and is dull, aching, poorly-localized pain. visceral pain originates in the viscera (organs). visceral pain may be well-localized, but often it is extremely difficult to locate, and several visceral regions produce "referred" pain when damaged or inflamed, where the sensation is located in an area distant from the site of pathology or injury. neuropathic pain is divided into "peripheral" (originating in the peripheral nervous system) and "central" (originating in the brain or spinal cord). peripheral neuropathic pain is often described as "burning", "tingling", "electrical", "stabbing", or "pins and needles". causes pathophysiology under persistent activation, the transmission of pain signals to the dorsal horn may produce a pain wind-up phenomenon. this triggers changes that lower the threshold for pain signals to be transmitted. in addition, it may cause nonnociceptive nerve fibers to respond to, generate, and transmit pain signals. the type of nerve fibers that are believed to generate the pain signals are the c-fibers, since they have a slow conductivity and give rise to a painful sensation that persists over a long time. in chronic pain, this process is difficult to reverse or stop once established. in some cases, chronic pain can be caused by genetic factors which interfere with neuronal differentiation, leading to a permanently lowered threshold for pain. chronic pain of different causes has been characterized as a disease that affects brain structure and function. mri studies have shown abnormal anatomical and functional connectivity, even during rest involving areas related to the processing of pain. also, persistent pain has been shown to cause grey matter loss, which is reversible once the pain has resolved. these structural changes can be explained by neuroplasticity. in the case of chronic pain, the somatotopic representation of the body is inappropriately reorganized following peripheral and central sensitization. this can cause allodynia or hyperalgesia. in individuals with chronic pain, eegs showed altered brain activity, suggesting pain-induced neuroplastic changes. more specifically, the relative beta activity (compared to the rest of the brain) was increased, the relative alpha activity was decreased, and the theta activity was diminished. dysfunctional dopamine management in the brain could potentially act as a shared mechanism between chronic pain, insomnia and major depressive disorder. astrocytes, microglia, and satellite glial cells have also been found to be dysfunctional in chronic pain. increased activity of microglia, alterations of microglial networks, and increased production of chemokines and cytokines by microglia might aggravate chronic pain. astrocytes have been observed to lose their ability to regulate the excitability of neurons, increasing spontaneous neural activity in pain circuits. management main article: pain management pain management is a branch of medicine that uses an interdisciplinary approach. the combined knowledge of various medical professions and allied health professions is used to ease pain and improve the quality of life of those living with pain. the typical pain management team includes medical practitioners (particularly anesthesiologists), rehabilitation psychologists, physiotherapists, occupational therapists, physician assistants, and nurse practitioners. acute pain usually resolves with the efforts of one practitioner; however, the management of chronic pain frequently requires the coordinated efforts of a treatment team. complete, longterm remission of many types of chronic pain is rare. nonopioids initially recommended efforts are non-opioid based therapies. non-opioid treatment of chronic pain with pharmaceutical medicines might include acetaminophen (paracetamol) or nsaids. various other nonopioid medicines can be used, depending on whether the pain is a result of tissue damage or is neuropathic (pain caused by a damaged or dysfunctional nervous system). there is limited evidence that cancer pain or chronic pain from tissue damage as a result of a conditions (e.g. rheumatoid arthritis) is best treated with opioids. for neuropathic pain other drugs may be more effective than opioids, such as tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors, and anticonvulsants. some atypical antipsychotics, such as olanzapine, may also be effective, but the evidence to support this is in very early stages. in women with chronic pain, hormonal medications such as oral contraceptive pills ("the pill") might be helpful. when there is no evidence of a single best fit, doctors may need to look for a treatment that works for the individual person. it is difficult for doctors to predict who will use opioids just for pain management and who will go on to develop an addiction. it is also challenging for doctors to know which patients ask for opioids because they are living with an opioid addiction. withholding, interrupting or withdrawing opioid treatment in people who benefit from it can cause harm. interventional pain management may be appropriate, including techniques such as trigger point injections, neurolytic blocks, and radiotherapy. while there is no high quality evidence to support ultrasound, it has been found to have a small effect on improving function in non-specific chronic low back pain. psychological treatments, including cognitive behavioral therapy and acceptance and commitment therapy can be helpful for improving quality of life and reducing pain interference. brief mindfulness-based treatment approaches have been used, but they are not yet recommended as a first-line treatment. the effectiveness of mindfulness-based pain management (mbpm) has been supported by a range of studies. among older adults psychological interventions can help reduce pain and improve self-efficacy for pain management. psychological treatments have also been shown to be effective in children and teens with chronic headache or mixed chronic pain conditions. while exercise has been offered as a method to lessen chronic pain and there is some evidence of benefit, this evidence is tentative. for people living with chronic pain, exercise results in few side effects. opioids in those who have not benefited from other measures and have no history of either mental illness or substance use disorder treatment with opioids may be tried. if significant benefit does not occur it is recommended that they be stopped. in those on opioids, stopping or decreasing their use may improve outcomes including pain. some people with chronic pain benefit from opioid treatment and others do not; some are harmed by the treatment. possible harms include reduced sex hormone production, hypogonadism, infertility, impaired immune system, falls and fractures in older adults, neonatal abstinence syndrome, heart problems, sleep-disordered breathing, opioid-induced hyperalgesia, physical dependence, addiction, abuse, and overdose. alternative medicine alternative medicine refers to health practices or products that are used to treat pain or illness that are not necessarily considered a part of conventional medicine. when dealing with chronic pain, these practices generally fall into the following four categories: biological, mind-body, manipulative body, and energy medicine. implementing dietary changes, which is considered a biological-based alternative medicine practice, has been shown to help improve symptoms of chronic pain over time. adding supplements to one's diet is a common dietary change when trying to relieve chronic pain, with some of the most studied supplements being: acetyl-l-carnitine, alpha lipoic acid, and vitamin e. vitamin e is perhaps the most studied out of the three, with strong evidence that it helps lower neurotoxicity in those with cancer, multiple sclerosis, and cardiovascular diseases. hypnosis, including self-hypnosis, has tentative evidence. hypnosis, specifically, can offer pain relief for most people and may be a safe alternative to pharmaceutical medication. evidence does not support hypnosis for chronic pain due to a spinal cord injury. preliminary studies have found medical marijuana to be beneficial in treating neuropathic pain, but not other kinds of long term pain. as of 2018, the evidence for its efficacy in treating neuropathic pain or pain associated with rheumatic diseases is not strong for any benefit and further research is needed. for chronic non-cancer pain, a recent study concluded that it is unlikely that cannabinoids are highly effective. however, more rigorous research into cannabis or cannabis-based medicines is needed. tai chi has been shown to improve pain, stiffness, and quality of life in chronic conditions such as osteoarthritis, low back pain, and osteoporosis. acupuncture has also been found to be an effective and safe treatment in reducing pain and improving quality of life in chronic pain including chronic pelvic pain syndrome. transcranial magnetic stimulation for reduction of chronic pain is not supported by high quality evidence, and the demonstrated effects are small and short-term. spa therapy could potentially improve pain in patients with chronic lower back pain, but more studies are needed to provide stronger evidence of this. while some studies have investigated the efficacy of st john's wort or nutmeg for treating neuropathic (nerve) pain, their findings have raised serious concerns about the accuracy of their results. kinesio tape has