How much of this condition's readable clinical evidence the confidence engine has incorporated, across its most-studied treatments. This measures coverage of the evidence base — not whether any treatment works.

Limited evidence coverage

39% · 67/174 eligible items incorporated

Largest gap: no meaningful change (56, trial-readability).

Regulatory timeline

Drug regulatory events matched to this condition by indication — EMA.

First approvals

2010emaApproval — Fentanyl· PecFent is indicated for the management of breakthrough pain in adults who are already receiving maintenance opioid therapy for chronic cancer pain. Breakthrough pain is a transitory exacerbation of pain that occurs on a background of otherwise controlled persistent pain. Patients receiving maintenance opioid therapy are those who are taking at least 60 mg of oral morphine daily, at least 25 micrograms of transdermal fentanyl per hour, at least 30 mg of oxycodone daily, at least 8 mg of oral hydromorphone daily or an equi-analgesic dose of another opioid for a week or longer. source ↗

2009emaApproval — Fentanyl· Instanyl is indicated for the management of breakthrough pain in adults already receiving maintenance opioid therapy for chronic cancer pain. Breakthrough pain is a transitory exacerbation of pain that occurs on a background of otherwise controlled persistent pain. Patients receiving maintenance opioid therapy are those who are taking at least 60 mg of oral morphine daily, at least 25 micrograms of transdermal fentanyl per hour, at least 30 mg oxycodone daily, at least 8 mg of oral hydromorphone daily or an equianalgesic dose of another opioid for a week or longer. source ↗

2008emaApproval — Fentanyl· Effentora is indicated for the treatment of breakthrough pain (BTP) in adults with cancer who are already receiving maintenance opioid therapy for chronic cancer pain. BTP is a transitory exacerbation of pain that occurs on a background of otherwise controlled persistent pain. Patients receiving maintenance opioid therapy are those who are taking at least 60 mg of oral morphine daily, at least 25 micrograms of transdermal fentanyl per hour, at least 30 mg of oxycodone daily, at least 8 mg of oral hydromorphone daily or an equianalgesic dose of another opioid for a week or longer. source ↗

2005emaApproval — Ziconotide· Ziconotide is indicated for the treatment of severe, chronic pain in patients who require intrathecal (IT) analgesia. source ↗

European Medicines Agency (CC BY 4.0). Events are matched to this condition by drug indication text — approvals/updates for drugs indicated for it, not disease-specific acts.

Research activity

36 papers

Key research shaping understanding of this disease, combining the latest publications with the most influential evidence.

Publications over time

20142026

Most influential

Chronic pain as a symptom or a disease: the IASP Classification of Chronic Pain for the International Classification of Diseases (ICD-11).

Pain · 2019 · 2,069 cites

CDC Guideline for Prescribing Opioids for Chronic Pain - United States, 2016.

MMWR. Recommendations and reports : Morbidity and mortality weekly report. Recommendations and reports · 2016 · 1,971 cites

Cannabinoids for Medical Use: A Systematic Review and Meta-analysis.

JAMA · 2015 · 1,366 cites

CDC Clinical Practice Guideline for Prescribing Opioids for Pain - United States, 2022.

MMWR. Recommendations and reports : Morbidity and mortality weekly report. Recommendations and reports · 2022 · 1,112 cites

Mechanisms of acupuncture-electroacupuncture on persistent pain.

Anesthesiology · 2014 · 587 cites

The Link between Depression and Chronic Pain: Neural Mechanisms in the Brain.

Neural plasticity · 2017 · 476 cites

Recent publications

Predictors of Success for 60-Day Peripheral Nerve Stimulation Used for Treatment of Chronic Shoulder Pain: A Multicenter Retrospective Chart Review.

American journal of physical medicine & rehabilitation · 2026

Lumbar Multifidus Dysfunction and Chronic Low Back Pain: Overview, Therapies, and an Update on the Evidence.

Pain practice : the official journal of World Institute of Pain · 2025 · 6 cites

CHOP-Mediated Disruption of Hippocampal Synaptic Plasticity and Neuronal Activity Contributes to Chronic Pain-Related Cognitive Deficits.

CNS neuroscience & therapeutics · 2025 · 4 cites

Psychedelic-assisted Therapy as a Promising Treatment for Irritable Bowel Syndrome.

Journal of clinical gastroenterology · 2025 · 2 cites

Pain, quality of life, and function in chronic intractable leg pain were substantially improved with 10kHz spinal cord stimulation in a multicentre European study.

European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society · 2025 · 1 cites

The Role of the Brain-Derived Neurotrophic Factor in Chronic Pain: Links to Central Sensitization and Neuroinflammation.

Biomolecules · 2024 · 67 cites

Major themes8

Chronic Pain23
Pain Management3
Spinal Cord Stimulation3
Nervous System Diseases2
Neuralgia2
Neuronal Plasticity2
Neurons2
Stress Disorders, Post-Traumatic2

Leading journals6

International journal of molecular sciences3
MMWR. Recommendations and reports : Morbidity and mortality weekly report. Recommendations and reports2
American journal of physical medicine & rehabilitation1
Anesthesiology1
Annual review of genomics and human genetics1
Autophagy1

Leading researchers8

Wang J3
Zhang Y3
Boggs JW2
Chou R2
Crosby ND2
Dowell D2
Huffman WJ2
Lavand'homme P2

Affiliations (unnormalised)6

Medical School2
Oslo University Hospital2
Radboud University Medical Center2
School of Basic Medical Sciences2
University of Pittsburgh2
*Center for Clinical Research and Carolina's Pain Institute1

Related conditions

8 matches

Diseases frequently studied alongside this one. Number shows shared papers.

Neuralgia6 Mental Disorders3 Acute Pain2 Neoplasms2 Nervous System Diseases2 Neuroinflammatory Diseases2 Opioid-Related Disorders2 Stress Disorders, Post-Traumatic2

Disease profile

A grounded synthesis of the condition — overview, causes, mechanism, risk factors and current standard of care.

Overview

Chronic pain is pain that persists or recurs for more than 3 months. It may be a symptom of an underlying condition or a pain syndrome in which pain is the main complaint, and it often interferes with daily functioning and is accompanied by distress.

Causes

It may or may not be associated with trauma or disease, and it can persist after the initial injury has healed. The grounding also supports chemically induced chronic pain as a recognized aspect, but does not provide more specific causes.

Pathophysiology

The literature grounding links chronic pain with changes in neuroplasticity and signal transduction. Review material also notes overlap between pain- and depression-related neuroplasticity changes, and co-studies brain-derived neurotrophic factor, suggesting involvement of brain and spinal mechanisms in persistent pain states.

Risk factors

The supplied grounding does not identify specific risk factors for developing chronic pain. It does note that chronic pain commonly coexists with distress and can be associated with depression, but this is not presented as a causal risk factor.

Current standard of care

The grounding supports multimodal pain management as an important care approach for chronic pain. It also supports opioid therapy as a treatment class considered in chronic pain care, with guidelines addressing when to initiate or continue opioids and how to assess risks and harms, and it includes cannabinoids and acupuncture-electroacupuncture as studied treatment modalities for chronic pain.

AI-generated summary grounded in MeSH and 6 peer-reviewed sources. Informational only — not medical advice. Generated 2026-07-07.

Reference

Authoritative identity, definition & identifiers.

Defined in MeSH

Aching sensation that persists for more than a few months. It may or may not be associated with trauma or disease, and may persist after the initial injury has healed. Its localization, character, and timing are more vague than with acute pain.

Identifiers

MeSHChronic Pain

References & data sources

Disease identity & definition — NLM Medical Subject Headings (MeSH), public domain
Clinical trials — ClinicalTrials.gov (U.S. National Library of Medicine)
Research activity — Europe PMC (EMBL-EBI) + OpenAlex-derived paper links
Related entities are derived from literature co-mention (studied together) — associative, not causal.