Health Psychology - Session 11 Psychological aspects of pain Dr. Caroline Meyer

Outline of session - definitions of pain - including psychological conceptualisation of pain - measurement issues - theories of pain perception - psychological pain management

Objectives - evaluate relationship between sensation (e.g., tissue damage) and experience - outline psychological theories of pain perception - evaluate attempts to measure pain - describe social & psychological factors involved in pain perception

Definitions Although pain is a universal experience, due to its subjectivity, definitions vary. Example definition: an unpleasant sensory and emotional experience associated with actual or potential tissue damage “ there is no direct relationship between physical pathology and the intensity of pain” IASP, (1993)

Nature of pain - Psychological components 1. Sensory - location, magnitude, sensation (e.g., burning, aching, stabbing) 2. Emotional response - strong negative emotional states (e.g., fear, nausea, anxiety, depression, exhaustion) 3. Evaluative - cognitive responses (unbearable, miserable, annoying, frustrating) Individuals cognitive response can have an effect on pain perception (e.g., Morley, 1997 - catastrophizing)

Duration of pain Acute - e.g., injections, post-surgical Chronic - e.g., back pain, cancer Different meanings - acute is often ‘expected’ to be short lived and is therefore more bearable than chronic.

Measurement of pain Why is it important? - gives health professionals information (e.g., degree of discomfort, severity of problem ?diagnosis) - associated with patient satisfaction (e.g., Bruster, 1994) - increases medical knowledge - leads to investigation Two types of measures: Objective Self-report

Objective measures - include physiological measures (heart-rate, skin conductance, muscle tension - electromyography (EMG) readings) Problems with ‘objective’ measures: - imply relationship between sensation and experience of pain - weak correlation between physiological measures and reported intensity of pain - other factors may effect physiological readings (mood, stress, diet, exercise) - less useful for chronic pain

Self-report measures of pain There is currently no truly objective way of measuring pain. It is also insufficient to use NVC - Fritz (1988) Patients self-report is the most reliable indicator (e.g., Beyer et al, 1990). One method of assessment is the Visual Analogue Scale (VAS) No pain Worst possible pain 10cm Correlates well with verbal reports of pain intensity issue about perceptual set / relativity

As well as pain intensity, it is useful to be able to measure other components (sensation, emotion) McGill Pain Questionnaire (MPQ - Melzack, 1975) - VAS - present pain - adjectives describing sensory experience (e.g., Throbbing, Sharp) - items describing emotional impact (e.g., tiring-exhausting, fearful) All rated on a 4-point scale - none (1), mild (2), moderate (3), severe (4)

McGill Pain Questionnaire, continued.. - has been found to be a valid measure of pain (gives a true reflection of the type, extent and impact of the individual’s current state) - However, it requires wide vocabulary & ability to make very specific distinctions between different sensations and different levels Other alternatives have now been developed to overcome these issues (e.g., Wong/Baker faces rating scale for children,1986)

Measures of pain behaviour - e.g., facial expressions, verbal complaints, postural changes, medication consumption - usually measured by observation (in structured setting - e.g., physiotherapy) - poor correlation with self-report measures, subject to observer bias (e.g., Morley, 1997), increased pain behaviour under certain circumstances (e.g., when spouse present) - pain behaviours may represent attempts to avoid pain rather than reaction to pain

Other psychological considerations - people can report pain in the absence of physiological problem (Somatoform Pain Disorder, DSMIV - American Psychiatric Association) - people can report feeling no pain when physiologically it is clear that they should (Dissociation - amnesia, depersonalisation; Alzheimers disease - Scherder et al., 1999, 2000) - people can deny pain (under report) for many reasons (e.g., cultural - stiff upper lip; fear of addiction to pain relief medication)

Theories of pain Early theories - automatic response; early biomedical models direct link between biological state and pain perception - believed pain to be linearly related to extent of tissue damage / intensity of stimulus BUT: there is not always a clear link (e.g., cause of back pain is unknown in upto 80% of cases; Deyo, 1986)

Gate control theory (Melzack & Wall, 1965) - gate mechanism modulates pain signals (encompasses both sensory / perceptual information and brain function) - integrates psychology into the stimulus-response theories of pain

Gate control theory, continued Brain expectations experience mood behaviour Gate Action system PAIN Physiological stimuli (from injury) Large fibres Small fibres Taken from Ogden (2000) - activity in large nerve fibres (touch) inhibits sensation of pain - signals from cortex can alter the sensation of pain

Influences on pain perception - what opens the gate? Physical factors - injury, activation of small (pain) fibres Emotional factors - anxiety, tension, worry, depression all linked to pain ? Cause & effect e.g., depression magnifies -ve effects of pain (e.g., Verma & Gallagher, 2000) Behavioural factors - attention to pain, boredom,

Influences on pain perception - what closes the gate? Physical factors - medication,stimulation of large (touch) fibres Emotional factors - happiness, optimism, relaxation Behavioural Factors - concentration, distraction e.g., Shiloh et al (1998, Cognitive Therapy & Research) high levels of distraction associated with lower pain reports during childbirth Pain competes for processing space (Morley,1997)

What other factors might alter the way in which pain is perceived? 1. Gender no evidence of gender differences in pain perception or types of coping (e.g., Holden et al., 1998) 2. Age - previously believed that infants were less sensitive to pain - no less sensitive than adults & early experience can have long term effects (physically & psychologically)

- no evidence that elderly patients cope better with pain, although decreased experience in some cases (related to dementia) 3. Personality - ? Is there individual variation in ability to: detect sensations, pain thresholds, tolerance - evidence is equivocal - recent study suggests link between extroversion and self-reported pain in women receiving gynaecological treatment (Joseph, 1999)

4. Anxiety and depression - can be cause or consequence of pain - treating anxiety and depression (as well as pain) may help in some cases - ? depends upon type of pain; acute pain treatment anxiety - e.g., Fordyce & Steger (1979) chronic pain ineffective treatment anxiety

5. Self-efficacy - low self-efficacy associated with increased avoidance (e.g., not engaging in activity due to feeling as though it will not be effective) - high levels of self-efficacy associated with low levels of reported pain (e.g., in childbirth; Shiloh et al., 1998) 6. Memory - some evidence that memories of pain are unreliable (e.g., recall of labour pain - underestimated)

Psychological management of pain Two main aims: - help patients to cope more effectively - reduce reliance on drugs Relaxation - different techniques (e.g., progressive muscle relaxation) relaxation is incompatible with stress - helpful because stress and anxiety are important in onset of pain;

- stress has been found to be a significant predictor of intensity of pain (e.g., in Sickle Cell disease; Porter et al., 1998, 2000) - also, differential responses to stress in those with and without pain Hassinger et al. (1999). Frequent migraines associated with different physiological response to stress (cardiac output, stroke volume) Stress can also reduce reliance on several coping techniques (e.g., distraction - rumination)

Hypnosis - only 15-30% can be hypnotised - little evidence of efficacy ? placebo

Behavioural - e.g., Fordyce (1984) - aims to reduce disability - focuses on pain behaviours (e.g., excessive resting) - works on the assumption that pain behaviours are reinforced (operant conditioning) e.g., care, sympathy (+ve reinforcement) and avoidance of unpleasant events (-ve reinf.) - Treatment consists of: - identifying stimuli, behaviours & reinforcers - reduction of reinforcement for pain behavs. - increasing ‘well’ behaviours by social reinforcement

Cognitive Behavioural Treatments e.g., Turk & Fernandez (1991) - help patient to re-interpret their pain & associated problems - tailored to individual: Includes; i) initial pain assessment ii) cognitive therapy or re-structuring - - focuses on appraisals, expectations & beliefs about origin & consequences of pain e.g., catastrophising beliefs may be challenged with alternatives to provide increased sense of control over pain

- redefinition of pain (seen as less negative) - improving mood (reconceptualize problems until viewed as managable) iii) Education / Information provision - information about different models of pain - helps to engage patient in treatment - requires reflection on individual’s own understanding of pain iv) Exercise / activity / sleep management programmes (?changes beliefs / dysfunctional assumptions about disabilities)

Summary & tips - pain is a subjective experience comprising physical, sensory, emotional and cognitive responses - pain can be affected by: someone’s emotional state, expectations & beliefs - the most effective way of measuring pain involves self-report, but communication is important here (believe them even if there is little physiological evidence) - psychological treatments involve a range of techniques - cognitive restructuring, education, anxiety / depression management