Lecture 5: Organismic and Experiential Factors Flashcards
1
Q
How are individual differences in pain sensitivity measured?
A
- 500 people were given an identical thermal stimulus of 49 degrees.
- They were asked to rate the pain on a VAS.
2
Q
Why is there so much pain variability between people?
A
- People might have different perceptual experiences.
- But it can also be due to different interpretations of the pain scale.
3
Q
Was there any proof that the variability in pain ratings could be due to an actual perceptual difference?
A
- Coghill made a study where there was some evidence that there are different perceptual experiences.
- However if he did the study with more people, it wouldn’t be replicated.
4
Q
What proportion of people with cancer have cancer pain?
A
1/3
5
Q
What proportion of people with a stroke have shoulder pain?
A
1/4
6
Q
What proportion of people with diabetes have painful diabetic neuropathy?
A
1/4
7
Q
What proportion of people with trauma have causalgia?
A
about 1/5
8
Q
What proportion of people with shingles have post-herpetic neuralgia?
A
About 10 to 18%.
9
Q
What proportion of people with a stroke have post-stroke pain?
A
about 10%
10
Q
What proportion of people with a fracture have complex regional pain disorder?
A
very little amount like 3%
11
Q
What proportion of people getting surgery experience chronic post-surgical pain?
A
only 7%.
12
Q
How many surgeries are performed every year in Canada?
A
More than half a million?
13
Q
How were individual differences in analgesic response measured?
A
- 3170 postoperative patients were asked by the nurse to rate their pain every hour
- If that rating was above 40, the patients were assigned another dose of morphine.
- FOUND: very big variability in dose required : 2-83 ug/kG
14
Q
What would be the organismic (nature) reasons for inter individual variability?
A
- genetic background
- sex
- psychological traits
- age
- circadian rhythms
15
Q
What would be the environmental (nurture) reasons for inter individual variability?
A
- past experiences
- gender
- psychological states
- diet
- legal factors
- social factors
16
Q
What legal factors affect reported pain levels?
A
In a lawsuit.
17
Q
What is the biopsychological model?
A
3 factors that can influence individual differences:
- biological
- sociocultural
- psychological
18
Q
What was found in twin studies about the heritability of pain?
A
- For clinical pain. 40% heritable on average.
- For experimental pain: 40% heritable on average.
19
Q
What was found when studying the heritability of pain in inbred mouse strains?
A
About 40% heritable as well
20
Q
What are monogenic pain disorders?
A
- Pain due to dysfunction of some specific genes
- Very rare
21
Q
What gene comes up alot in monogenic pain disorders?
A
- SCN9A
- Variants in that gene are responsible for a number of pain disorders.
22
Q
What does HSAN stand for?
A
Hereditary Sensory and Autonomic Neuropathy
23
Q
What is the most important pain gene according to Mogil’s study?
A
- COMT
- Plays a role but we don’t know what
24
Q
In the OPPERA study, what did they find was a risk factor for developing TMD (Temporomandibular Disorder)?
A
somatization
25
How did they measure somatization in the OPPERA study?
2 questionnaires:
- PILL: Pennebaker Inventory of Limbic Languidness
- SCL 90R Somatization Subscore.
26
What was found about sex differences in chronic pain prevalence ? Berkley study
- 3 columns sort out pain disorder according to what sex it's most likely to be associated with.
- Approx 70% of chronic pain patients are women
27
Why might their be a sex difference in the amount of chronic pain patients ?
- social expectation that men are supposed to be stronger than women
- they don't go to the doctor as much so alot of male pain is not reported.
28
Mogil measured pain prevalence for male and female for different pain disorders. What were the findings of this study?
- In every case except one, women are more likely to say they have those symptoms, by approximately 5%.
- This might be because women are more sensitive to pain , but also because women are more likely to develop symptoms that featuring pain.
29
How do babies respond to pain stimulus?
- they are allodynic, they respond to very small forces
| - their response is also bilateral (if stimulus is on one leg, they will lift both legs
30
Are you more or less likely to be a pain patient as you age?
- You are LESS likely
| - counterintuitive
31
Why are you less likely to be a pain patient as you age?
- as you age you are more careful with your health, so you have less risk of being in pain for some reason
- there is an expectation of natural pain as you get older so you see it as "normal" and don't go to a doctor for it.
32
Older rats take longer to escape pain stimulus than younger rats. Why is that?
- Widespread supposition: they don't have as much pain
| - More plausible possibility: they don't have the same physical abilities as before.
33
Do Black people have higher pain levels or lower? What could be the reasons?
- higher pain levels were recorded in Black people
| - This could be genetic or environmental
34
When do most pains peak?
-In the morning
35
When does osteoarthritis of the knee peak?
In the evening because you are active all day long
36
Are you more at risk of being in pain if you are unemployed ?
Yes 3.1 times more risk
37
Are you more at risk of being in pain if you have physical exertion at work?
Yes 1.5 times more at risk
38
How much more at risk are you of experiencing chronic pain if your body mass index is bigger than 30?
1.9
39
How much more at risk are you of experiencing chronic pain if you are married for the first time?
1.6
40
How much more at risk are you of experiencing chronic pain if you are other than married for the first time or single?
2 times more at risk
41
In the study about pain and spousal support, how was the spouses response to their spouses pain coded?
- solicitousness: pity, poor baby can I do something
- punishment: stop complaining
- distraction: trying to change the subject
42
How were the different types of responses to spouses pain correlated with levels of pain?
- solicitousness: positively correlated, so more soli=more pain
- distraction: predicted lower pain scores
43
How does empathy for pain vary according to the subject that is in pain?
- If the person in pain is telling a sad story about themselves, more empathic for their pain
- If they are assholes, less empathy for their pain
44
How does laboratory environment affect pain of the subject?
Alot of random things will affect pain in laboratories, like rhythms, ambient conditions, testing surface...
45
What were the findings of the study with soy in rats?
-Lower pain if higher soy diet
46
In mice, how does empathy influence pain levels?
-If two cagemates are in pain together they will have higher pain than one mice alone, or two stranger mice together
47
who discovered the placebo effect and how did he discover it?
- Henry Beecher, medic during WW2
- Ran out of morphine, used saline solution, continued telling soldiers it was morphine
- Half of soldiers reported that the solution reduced or erased their pain
48
What reason is there to believe that the placebo effect is real?
- According to a study the clinical problem that placebo has most effect on is pain.
- but it was also the problem that had most participants relative to other issues studied in this study.
49
How can yo have placebo with conditioning?
- classical way: pavlovian
- If you are conditioned to the idea that the pill will have a certain effect, even if the pill doesn't do anything you will feel like it does
50
How can you have placebo with expectation and desire?
-When you expect or want the pain to get better, some mechanisms mIght engage that make you feel like it's better
51
What exact effects does placebo block?
It blocks specific effects, but not non-specific effects.
52
What percentage of people respond to placebo?
About 1/3 of people, around 30%
53
What pain conditions respond better to placebo than other pain conditions?
HIV and phantom pain
54
How do personality traits influence how you respond to placebo effect?
- anxious: less likely to respond, bad expectancy.
| - optimistic: more likely to respond, good expectancy.
55
When are you more likely to start a treatment?
When you think the pain is as bad as it could get.
56
How does subjectivity vs objectivity affect placebo effect?
The more subjective the pain is the more likely you are to have placebo effect.
57
How can the nature of verbal suggestions affect the placebo effect?
- More likely to have placebo if you are being told: it is a powerful painkiller
- rather than: it can be either placebo or painkiller
58
How does previous experience affect placebo effect?
If you take alot of analgesics in your everyday life and it works, you are more likely to have placebo effect.
59
How can belief, expectation and desire of the patient and clinician influence placebo effect?
-If the clinician believes in what he is prescribing, it results in more placebo for the patient
60
What factors in the patient-clinician interaction affects the placebo effect?
- "bedside manner": enthusiasm, reassurance, empathy, communication
- white coats
- deep voices
61
What physical properties of the treatment can affect placebo effect?
- sham surgery>i.v pleacebo>big pill>small pill
| - expensive pill>cheap pill
62
How is placebo opioid-mediated?
- placebo effect is mediated by the release of endogenous opioids
- this effect can be reversed by NALOXONE which is an opioid antagonist
63
What is rimonabant?
It is an antagonist to CB1 (cannabinoid neurotransmitters).
64
What is ketolorac?
- An NSAID: Non-steroidal anti-inflammatory drug
| - Acts as an analgesic
65
What are the effects of rimonabant on placebo effect?
- blocks the placebo analgesia that came with ketolorac
- Does not block the opioid placebo
- Does not block morphine or ketolorac
66
What is a nocebo effect?
opposite of placebo effect: you have pain with no actual stimulus
67
What is the most prevalent nocebo effect?
- voodoo
- people finding out a voodoo curse was put on them report experiencing voodoo torture
- clinicians saying negative things to the patients can also produce a nocebo effect
68
What does CCK do?
- cholecystokinin
| - Leads to hyperalgesia
69
What is an antagonist for CCK?
-proglumide: makes the placebo effect even stronger
70
In a clinical trial, is the placebo response solely due to placebo effect?
- no
| - circumstances like the nurse being nice, good service and the place being comfortable can increase placebo response
71
How has placebo response been evolving overtime?
- has been growing overtime
| - this is true for antipsycs, antidepressants and analgesics
72
How has drug response evolved overtime?
Drug response has remained constant overtime
73
What was the biggest change in American drug trials?
- Direct to consumer advertising on drug was allowed
| - Makes them believe more that the drug works
74
In what drug trials is placebo response bigger?
-bigger in trials studying diabetic neuropathy than in postherpetic neuralgia.
75
How can we try to reduce placebo response?
- could do trials on patients with lower placebo response
| - could test people for placebo analgesia first, then exclude those with large placebo response
76
Why is placebo in clinical trials lower than in the real-world?
- in clinical trials: subjects might understand that they're getting placebo
- in real world, people get real drugs
