date: 11/4/2013

1. Dr. Reem Al-Sabah
Faculty of Medicine
Psychology 220

2. What is pain?
 Pain is “an unpleasant sensory and emotional
experience associated with actual or potential
tissue damage or described in terms of such
damage.”
(The International Association for the Study of Pain)

3.  Pain is an almost universal experience, yet difficult to
define.
 Clinical Pain: Pain that requires some form of
medical treatment.
 Pain is the most common reason people seek
medical treatment.
 Pain appears to have an obvious function.

4. Why do we have pain?
 It provides constant feedback about the body
enabling us to make adjustments to how we sit or
sleep.
 A warning sign that something is wrong resulting in
protective behavior.
 It triggers help-seeking behavior .
 It has psychological consequences and can generate
fear and anxiety.

5. Types of Pain
Pain has been classified into three stages:
1. Acute. adaptive and meaningful (pain from cuts, burns,
surgery, and other injuries).
2. Chronic. When enough time for normal healing has
elapsed but the pain shows few signs of going away
(6months to years). Often experienced in the absence of
any detectable tissue damage.
3. Prechronic. A critical time when the person either
begins to heal and overcome the pain or lose hope and
develop feelings of helplessness that lead to chronic
pain.

6. The Pain Pathway
1. Transduction
2. Transmission
3. Modulation
4. Perception

8. Transduction
 The process by which afferent nerve endings translate
noxious stimuli (e.g., a bee sting) into nociceptive
impulses.
 There are three types of primary afferents:
1. A-beta carry information related to touch
2. A-delta  information related to pain and temperature
3. C-fibers information related to pain, temperature and itch
Nociceptors: receptors in the skin and organs that sense heat,
mechanical and chemical tissue damage.
Nociception: the process of perceiving pain.

9. Transmission
 Is the process by which impulses are sent to the dorsal
horn of the spinal cord, and then along the sensory tracts
to the brain.
 Pain impulses are transmitted by two fiber systems:
1. fast, sharp and well localized sensation (first pain)
which is conducted by A-delta fibers.
2. duller slower onset and often poorly localized
sensation (second pain) which is conducted by C-
fibers.

10. Modulation
 It is the process of either dampening or amplifying the
pain-related neural signals.
 Periaqueductal gray (PAG) in the midbrain is
involved in modualting of pain.
 descending inhibitory input dampens, or entirely
blocks incoming (ascending) nociceptive signals at the
“gate” of the dorsal horns.

12. Perception
 The conscious awareness of the experience of pain.
 Perception results from the interaction of
transduction, transmission, modulation, psychological
aspects, and other characteristics of the individual.

13. Early Pain Theories
 Biomedical framework
 Pain is an automatic response to an external factor.
 Tissue damage causes the sensation of pain.
 The pain sensation has a single cause.
 Psychological factors have no causal influence.

14.  Pain was categorized into psychogenic or
organic pain
 Psychogenic pain: considered to be “all in the
patient’s mind” and was a label given to pain
when no organic basis could be found.
 Organic pain: regarded as “real pain” and was
the label given to pain when some clear injury
could be seen

15. Including psychology in theories of pain
 Several Observations in the 1920s:
1. Medical treatments for pain (e.g., drugs, surgery)
were generally only useful for treating acute pain,
and ineffective in treating chronic pain.
2. Individual’s with the same degree of tissue
damage, different in their reports of pain and/or
pain expression (e.g. Beecher, 1956).
3. Phantom limb pain (65% to 85% of amputees).

16. Gate Control Theory
 Proposed by Melzack & Wall (1965)
 The idea that there is a neural “gate” in the spinal
cord that regulates the experience of pain.
 Pain is not the result of a straight-through
sensory channel.
 Physiological and psychological causes.

17.  Descending central influences from the brain.
The brain sends information related to the
psychological state of the individual to the gate.
 Behavioral state (e.g., attention, focus on the
source of pain).
 Emotional state (e.g., anxiety, fear, depression).
 Previous experience or self-efficacy I dealing with
the pain (e.g., I have experienced this pain before
and know that it will go away).

18. How does the GCT differ from earlier
models of pain?
 Pain as a perception
 According to the GCT, pain is a perception and
experience rather than a sensation.
 The individual as active, not passive
 The individual no longer just responds passively
to painful stimuli, but actively interprets and
appraises this stimuli.

19.  The role of individual variability
 Variations in pain perception is understood in
terms of the degree of opening or closing of the
gate.
 The role of multiple causes
 The GCT suggests that many factors are involved
in pain perception, not just a singular physical
cause.

20.  Is pain ever organic?
 The GCT describes most pain as a
combination of physical and psychological.
 Pain and dualism
 The GCT suggests an interaction between the
mind and the body.

21. What opens the gate?
 The more the gate is opened, the greater the
perception of pain.
 Several factors open the gate:
 Physical factors (e.g., injury, activation of the large
fibers)
 Emotional factors (e.g., anxiety, worry, depression)
 Behavioral factors (focusing on the pain, boredom)

22. What closes the gate?
 Closing the gate reduces pain perception.
 Certain factors close the gate:
 Physical factors (e.g., medication, stimulation of
the small fibers)
 Emotional factors (e.g., happiness, optimism,
relaxation)
 Behavioral factors (focus, concentration,
distraction, or involvement in other activities)

23. Psychosocial aspects of pain

24. Operant
Classical conditioning
conditioning Anxiety
Meaning Fear
Pain
Self- Secondary
efficacy gains
Pain
Attention Catastroph behavior
-izing

25. The role of psychosocial
factors in pain perception
 Three-process-model of pain
1. Physiological processes (e.g., tissue damage, the
release of endorphins and changes in heart rate)
2. Subjective-affective-cognitive processes
3. Behavioral processes

26. Subjective-affective-cognitive processes
 The role of learning
 Classical conditioning
(e.g., associating dentist with pain due to past
experience).
 Operant conditioning
(e.g., pain behavior may be positively reinforced
which may itself increase pain perception).

27.  The role of affect (emotion)
 Anxiety
 Worry and anxiety relate to pain perception.
 Acute pain increases anxiety.
 Chronic pain treatment ineffective increases
anxiety increases pain.
 Fear
 Fear of pain and fear avoidance beliefs.
 Exacerbate existing pain and turn acute pain to
chronic.

28.  The role of cognition
 Catastrophizing
 Rumination
 Magnification
 helplessness
 Meaning
 Pain has different meanings to different
people
 Attention
 Attention to pain can increase perception of pain
 Distraction reduces pain

29. Behavioral processes
 Pain behavior and secondary gains.
 The way a person responds to pain can increase
or decrease pain perception.

30. Psychosocial Factors in the Experience of Pain
 Age
 As people get older, there is a progressive
increase in reports of pain and a decrease
in tolerance to pain.
 A normal consequence of aging? Or do other
factors (overall health, coping resources,
differences in socialization) account for
age-related differences?

31.  Gender
 Women report more frequent episodes of pain than
men, including more migraines, tension headaches,
pelvic pain, facial pain, lower back pain.
 Gender differences already apparent by adolescence
and in medicine’s differential response to the pain
reports of women and men.
 Gender difference in pain physiology? Certain
analgesics may be more effective for women than for
men.

32. Is There a Pain-Prone Personality?
 Acute and chronic pain sufferers show elevated
scores on two MMPI scales:
 Hysteria (tendency to exaggerate symptoms and
use emotional behavior to solve problems).
 Hypochondriasis (tendency to be overly
concerned about health and to over report body
symptoms).
 Chronic pain sufferers also score high in depression.

33. Is There a Pain-Prone Personality?
 Dysfunctional patients
 Report high levels of pain, feel they have little
control over their lives, and are extremely inactive.
 Interpersonally distressed patients
 Perceive little social support and feel other people in
their lives don’t take their pain seriously.
 Adaptive copers
 Report lower levels of pain and distress and
continue to function at a high level.

34. Sociocultural Factors
 Groups differ greatly in their
norms for the degree to which
suffering should be openly
expressed and the form that pain
behaviors should take
 Pain tolerance versus pain
threshold

35.  Pain tolerance: The greatest level of pain that a
subject is prepared to tolerate
 Pain threshold: The least experience of pain that
a subject can recognize.

36. Measuring Pain
 Psychophysiological Measures
 Electromyography (EMG) — assess the amount
of muscle tension experienced by pain sufferers
 Indicators of autonomic arousal — using
measures of heart rate, breathing rate, blood
pressure, etc. to measure pain
 Physiological measures are not as reliable or
valid as self-reports or behavioral observations.

37. Measuring Pain
 Behavioral Measures
 Pain Behavior Scale
 Self-Report Measures
 Pain rating scales (numerical ratings or a pain diary)
 Standardized pain inventories
 McGill Pain Questionnaire (MPQ): sensory
quality, affective quality, evaluative quality of pain

38. Pain Intensity Scales

39. Myths about Children and Pain
Myth Truth
Young infants do The CNS of a 26-week-old fetus
not feel pain possesses the anatomical and
neurochemical capabilities of
sensing pain
Children easily become Less than 1% of children treated
addicted to narcotics with opioids develop addiction.
Children tolerate pain better Children's tolerance for pain
than adults increases with age
Children are unable to tell Children may not be able to
you where they hurt express their pain in the same
manner as adult

40. Myths (Cont.)
Myth Truth
Children become accustomed Children exposed to repeated
to pain or painful procedures painful procedures often
experience increasing anxiety
Children will tell you when Children may not report pain
they are experiencing pain
Children's behavior reflects Children are unique in their ways
their pain intensity of coping.
Texas Children’s Cancer Center, Texas Children’s Hospital. Houston, Texas.