Chronic Pain
Epidemiology
Pain is an unpleasant sensory and emotional experience associated with actual or potential
tissue damage or described in terms of such damage. Pain is a highly individualized
experience. Classification of pain:
o According to underlying disease:
Nociceptive pain: injury or pathology of the musculoskeletal system (somatic pain:
surface of the body or musculoskeletal tissues, visceral pain: internal areas of the
body).
Neuropathic pain: damage or dysfunction of the nerves that carry information about
pain.
Mixed pain: both nociceptive and neuropathic elements are present (e.g. herniated
disc).
Idiopathic pain: pain in the absence of evidence of injury or another organic
pathology.
o According to duration: acute or chronic.
o According to frequency: transient or brief (bump), intermittent (migraine) or constant
(low back pain).
o Other classifications: severity, functional consequences, cancer-related or not.
Acute pain: pain that lasts <6 months (before) or within a specified time frame for a given
condition (now). Acute pain serves a useful purpose as it signals potential damage to
muscles, tissue, nerves and is adaptive as it protects the body against further damage.
Chronic pain: pain that lasts >6 months (before) or pain that persists beyond the time one
would expect normal healing to occur, or pain that is associated with a chronic progressive
disease (now). Chronic pain serves no useful purpose (no warning of bodily harm) and is not
adaptive as it leads to disability.
Psychological factors (thoughts and emotions) play a part in acute pain. However, they play a
much bigger part in chronic pain conditions. Therefore, everyone experiences different levels
of pain (subjective).
Acute pain can become chronic pain by physical (e.g. bed rest) and mental deconditioning
(distress).
Most prevalent chronic pain condition: irritable bowel syndrome (20%), osteoarthritis (15%),
low back pain (14%), pelvic pain (12%), migraine headaches (12%), tension headaches (3%)
and fibromyalgia (2%).
Explanatory models for chronic pain:
o Unidimensional models: biomedical model, psychogenic perspective, learning model.
o Multidimensional models: gate control model, biopsychosocial model, cognitive-
behavioural transactional model, cognitive-behavioural fear-avoidance model.
Consequences of chronic pain: emotional distress, impaired occupational functioning
(absenteeism and reduced productivity), impaired social functioning and increased use of
health care system resources. Patients inability to engage in occupational, social or
recreational activities that they previously found enjoyable may contribute to increased
social isolation, negative moods (e.g. feelings of worthlessness and depression) and physical
deconditioning, which in turn can contribute to the experience of pain. Over time, these
negative cognitive and behavioural patterns can become highly resistant to change.
Psychosocial factors
Psychosocial factors influence the experience, course and consequences of pain:
Demographic characteristics: race, ethnicity, gender, class and age (pain is a natural part of
growing older and life disruption depends on age)
Developmental factors: cognitive ability
Coping: problem-focused and emotion-focused
Temperament
,Social support
Family interactions
Culture
Illness beliefs
Comorbid psychopathology
Depression
Anxiety and heightened anxiety sensitivity (the fear of arousal-related sensations arising
from beliefs that these sensations have harmful consequences)
Substance use disorders: chronic pain affects 24-67% of patients with substance use
disorders.
PTSD: some chronic pain conditions develop secondary to injury, related to traumatic life
events, such as motor vehicle accidents, occupational injuries or military combat.
Assessment
Comprehensive pain assessment: needed to develop a thorough understanding of the pain
condition.
Clinical interview (first phase): patients describe their pain condition and how it has impacted
their life.
Self-report measures:
o Unidimensional instruments to measure pain intensity or severity (e.g. visual analogue
scales, diary).
o Multidimensional instruments to measure multiple characteristics of pain (e.g. intensity
and quality). The McGill Pain Questionnaire (MPQ) and adaptions (e.g. Short-Form McGill
Pain Questionnaire).
o Measuring pain behaviour: UAB Pain Behaviour Scale
o Measuring fatigue: Checklist Individual Strength (CIS)
o Psychological assessment:
Emotions: anxiety and depression (Symptom Checklist 90R (SCL-90R), Hospital
Anxiety and Depression Scale (HADS), Beck Depression Inventory (BDI), State Trait
Anxiety Inventory (STAI)) and fear of movement (Tampa Scale for Kinesiophobia).
Cognitions: Pain Cognitions List, Pain Catastrophizing Scale.
Coping: Pain Coping Strategies Questionnaire
Quality of life: generic (Short Form (36) Health Survey (SF-36), Sickness Impact
Profile (SIP)) and disease-specific (e.g. Arthritis Impact Measurement Scales (AIMS))
Interventions
Cognitive behavioural therapy (CBT) for pain:
o Goal: promote the adoption of an active problem-solving approach to tackling challenges
associated with the chronic pain experience. Targets maladaptive cognitive and
behavioural coping.
o Tries to break through the vicious cycle of pain: injury pain catastrophizing
(cognition) anxiety hypervigilance (coping) and avoidance behaviour disuse,
hindrance, depression more pain.
o Key components: cognitive restructuring, coping skills, relaxation training and exposure
to feared activities to decrease avoidance behaviour and fear of movement (pacing).
o Effectiveness: effective for several chronic pain conditions, results in improvements in
pain experience, mood, coping, pain cognitions, activity levels and reductions in
behavioural expressions of pain. It helps patients to develop a healthier, active lifestyle,
while improving their QOL. Acceptance-based therapies (mindfulness based stress
reduction programs and ACT) have comparable effects.
Multidisciplinary pain rehabilitation program: treatment of choice for recalcitrant chronic
pain.
o Philosophy: maximizing functioning when meaningful pain reduction is not possible.
, o Characteristics: teaching self-management techniques, focus on collaborative
multidisciplinary care, psychological aspects are central (especially behavioural and
cognitive component).
Epidemiology
Pain is an unpleasant sensory and emotional experience associated with actual or potential
tissue damage or described in terms of such damage. Pain is a highly individualized
experience. Classification of pain:
o According to underlying disease:
Nociceptive pain: injury or pathology of the musculoskeletal system (somatic pain:
surface of the body or musculoskeletal tissues, visceral pain: internal areas of the
body).
Neuropathic pain: damage or dysfunction of the nerves that carry information about
pain.
Mixed pain: both nociceptive and neuropathic elements are present (e.g. herniated
disc).
Idiopathic pain: pain in the absence of evidence of injury or another organic
pathology.
o According to duration: acute or chronic.
o According to frequency: transient or brief (bump), intermittent (migraine) or constant
(low back pain).
o Other classifications: severity, functional consequences, cancer-related or not.
Acute pain: pain that lasts <6 months (before) or within a specified time frame for a given
condition (now). Acute pain serves a useful purpose as it signals potential damage to
muscles, tissue, nerves and is adaptive as it protects the body against further damage.
Chronic pain: pain that lasts >6 months (before) or pain that persists beyond the time one
would expect normal healing to occur, or pain that is associated with a chronic progressive
disease (now). Chronic pain serves no useful purpose (no warning of bodily harm) and is not
adaptive as it leads to disability.
Psychological factors (thoughts and emotions) play a part in acute pain. However, they play a
much bigger part in chronic pain conditions. Therefore, everyone experiences different levels
of pain (subjective).
Acute pain can become chronic pain by physical (e.g. bed rest) and mental deconditioning
(distress).
Most prevalent chronic pain condition: irritable bowel syndrome (20%), osteoarthritis (15%),
low back pain (14%), pelvic pain (12%), migraine headaches (12%), tension headaches (3%)
and fibromyalgia (2%).
Explanatory models for chronic pain:
o Unidimensional models: biomedical model, psychogenic perspective, learning model.
o Multidimensional models: gate control model, biopsychosocial model, cognitive-
behavioural transactional model, cognitive-behavioural fear-avoidance model.
Consequences of chronic pain: emotional distress, impaired occupational functioning
(absenteeism and reduced productivity), impaired social functioning and increased use of
health care system resources. Patients inability to engage in occupational, social or
recreational activities that they previously found enjoyable may contribute to increased
social isolation, negative moods (e.g. feelings of worthlessness and depression) and physical
deconditioning, which in turn can contribute to the experience of pain. Over time, these
negative cognitive and behavioural patterns can become highly resistant to change.
Psychosocial factors
Psychosocial factors influence the experience, course and consequences of pain:
Demographic characteristics: race, ethnicity, gender, class and age (pain is a natural part of
growing older and life disruption depends on age)
Developmental factors: cognitive ability
Coping: problem-focused and emotion-focused
Temperament
,Social support
Family interactions
Culture
Illness beliefs
Comorbid psychopathology
Depression
Anxiety and heightened anxiety sensitivity (the fear of arousal-related sensations arising
from beliefs that these sensations have harmful consequences)
Substance use disorders: chronic pain affects 24-67% of patients with substance use
disorders.
PTSD: some chronic pain conditions develop secondary to injury, related to traumatic life
events, such as motor vehicle accidents, occupational injuries or military combat.
Assessment
Comprehensive pain assessment: needed to develop a thorough understanding of the pain
condition.
Clinical interview (first phase): patients describe their pain condition and how it has impacted
their life.
Self-report measures:
o Unidimensional instruments to measure pain intensity or severity (e.g. visual analogue
scales, diary).
o Multidimensional instruments to measure multiple characteristics of pain (e.g. intensity
and quality). The McGill Pain Questionnaire (MPQ) and adaptions (e.g. Short-Form McGill
Pain Questionnaire).
o Measuring pain behaviour: UAB Pain Behaviour Scale
o Measuring fatigue: Checklist Individual Strength (CIS)
o Psychological assessment:
Emotions: anxiety and depression (Symptom Checklist 90R (SCL-90R), Hospital
Anxiety and Depression Scale (HADS), Beck Depression Inventory (BDI), State Trait
Anxiety Inventory (STAI)) and fear of movement (Tampa Scale for Kinesiophobia).
Cognitions: Pain Cognitions List, Pain Catastrophizing Scale.
Coping: Pain Coping Strategies Questionnaire
Quality of life: generic (Short Form (36) Health Survey (SF-36), Sickness Impact
Profile (SIP)) and disease-specific (e.g. Arthritis Impact Measurement Scales (AIMS))
Interventions
Cognitive behavioural therapy (CBT) for pain:
o Goal: promote the adoption of an active problem-solving approach to tackling challenges
associated with the chronic pain experience. Targets maladaptive cognitive and
behavioural coping.
o Tries to break through the vicious cycle of pain: injury pain catastrophizing
(cognition) anxiety hypervigilance (coping) and avoidance behaviour disuse,
hindrance, depression more pain.
o Key components: cognitive restructuring, coping skills, relaxation training and exposure
to feared activities to decrease avoidance behaviour and fear of movement (pacing).
o Effectiveness: effective for several chronic pain conditions, results in improvements in
pain experience, mood, coping, pain cognitions, activity levels and reductions in
behavioural expressions of pain. It helps patients to develop a healthier, active lifestyle,
while improving their QOL. Acceptance-based therapies (mindfulness based stress
reduction programs and ACT) have comparable effects.
Multidisciplinary pain rehabilitation program: treatment of choice for recalcitrant chronic
pain.
o Philosophy: maximizing functioning when meaningful pain reduction is not possible.
, o Characteristics: teaching self-management techniques, focus on collaborative
multidisciplinary care, psychological aspects are central (especially behavioural and
cognitive component).
