What is pain?

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Last updated: April 2, 2025View editorial policy

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From the Guidelines

Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage, as recently redefined by the International Association for the Study of Pain (IASP) 1.

Definition of Pain

Pain serves as the body's warning system, alerting us to injury or illness. It can be acute (short-term) or chronic (lasting more than 3-6 months), and may be described as sharp, dull, aching, burning, or throbbing.

Mechanism of Pain

It's processed through specialized nerve receptors called nociceptors that transmit signals to the spinal cord and brain. The disruption of tissue integrity increases the discharge rate of nociceptive neurons and initiates a local inflammatory response sustained by a cascade of mediators and activation of immune cells 1.

Subjective Nature of Pain

Pain is subjective and influenced by physical, psychological, and social factors, which explains why people experience it differently. The brain processes these signals in multiple regions including the thalamus, somatosensory cortex, and limbic system, creating both the sensory perception and emotional response to pain.

Treatment Approaches

Treatment approaches vary depending on the cause and may include medications (like acetaminophen, NSAIDs, or opioids), physical therapy, psychological interventions, or complementary therapies. Understanding pain as both a physical and emotional experience helps explain why comprehensive pain management often requires addressing multiple aspects of a person's health.

Prevalence of Chronic Pain

Chronic pain is a prevalent condition worldwide, causing suffering, limitation of daily activities, and reduced quality of life 1. According to recent studies, the prevalence of moderate to severely disabling chronic pain is estimated to range between 10.4% and 14.3% in Europe 1.

Importance of Pain Management

Adequate management of chronic pain is not only a moral and ethical imperative but also mitigates against subsequent physical and psychological complications 1. Therefore, it is essential to prioritize pain management and provide comprehensive care to patients with chronic pain, considering their complex needs and potential co-existing comorbidities 1.

From the Research

Definition of Pain

  • Pain is a personal, subjective experience influenced by cultural learning, the meaning of the situation, attention, and other psychological variables 2
  • The International Association for the Study of Pain has published a revised definition of pain, but it remains narrow in its focus on sensory and emotional features of pain, failing to capture the substantial roles of cognitive and social core components of the experience 3

Types of Pain

  • Pain can be categorised as nociceptive (from tissue injury), neuropathic (from nerve injury), or nociplastic (from a sensitised nervous system) 4
  • There is considerable overlap in the different types of pain mechanisms within and between patients, so many experts consider pain classification as a continuum 4

Functions and Effects of Pain

  • Pain has many valuable functions, including signaling injury or disease, generating adaptive behaviors, and promoting healing through rest 2
  • Chronic pain exerts an enormous personal and economic burden, affecting more than 30% of people worldwide, and can be considered a disease with treatment and psychological implications 4
  • Pain can cause psychological distress and sleep problems, and these associations are bidirectional 4

Management and Treatment of Pain

  • A personalised multimodal, interdisciplinary treatment approach is recommended for chronic pain, which may include pharmacotherapy, psychotherapy, integrative treatments, and invasive procedures 4
  • Acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs) are first-line treatment options for most patients with acute mild to moderate pain, while opioids may be used for severe or refractory acute pain with caution and attention to minimizing risk 5, 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Pain.

Wiley interdisciplinary reviews. Cognitive science, 2013

Research

Pharmacologic Therapy for Acute Pain.

American family physician, 2021

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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