Placebo

Question 1

Definition of placebo

Answer 1

Control treatment with similar appearance of drug but without it’s specific activity

Question 2

What two groups are in a two arm trial?

Three arm trial?

Answer 2

Two arm trial:
Placebo group
Treatment group

Three arm trial:
Untreated group
Placebo group
Treatment group

Question 3

Placebo paradox?

Answer 3

Placebo in RCTs obscure treatment effect, they’re a nuisance and non-specific

VS

Placebo in Clinical Practice is useful and is a good clinical practice because it involves factors other than specific treatments

Question 4

Does placebo play a bigger role in acute pain or chronic pain?

Answer 4

Chronic pain

Question 5

Why is pain multidimensional?

Answer 5

• Pain has negative effect on Cognition and Emotion
• Emotion can affect Cognition and Pain positively or negatively
• Cognition can affect Emotion and Pain positively or negatively

Question 6

3 influences on the placebo effect

Answer 6

1. vPatient-Practitioner Interactions
2. Psychological Mechanisms
3. Neurochemistry

Question 7

How can a patient be informed about pain?

Answer 7

How much pain to expect
Cause of pain
How to deal with pain
Positive/Enthusiastic doctor

Question 8

What is a contextual factor that can influence placebo? Which one decreases pain?

Answer 8

Open Injection (decreases pain)
vs
Hidden Injection

Question 9

What are the three steps to pharmacological conditioning? What do they involve?

Answer 9

1. Pre-conditioning : Unconditioned stimulus and Neural stimulus separately
2. Acquisition : Unconditioned stimulus + Neural stimulus
3. Evocation : Conditioned stimulus

Question 10

Does Opioid Conditioning + Expectation Placebo involve endogenous opioids?
What about non-opioid conditioning?

Answer 10

Yes

No

Question 11

Non-opioid conditioning placebo is mediated with what receptor? Which antagonist what used to show this?

Answer 11

CB1

Rimonabant

Question 12

Placebo effect by conditioning with opioids involves ___________
Placebo effect by conditioning with non-opioids involves __________

Answer 12

endogenous opioids

endocannabinoids

Question 13

What is the effect of branding of headache pain?

Answer 13

ORDER OF EFFECTIVENESS:
Actual aspiring w/ branding
Aspirin w/ no branding
Branded placebo
Placebo
Nothing

Question 14

Clinical example of how placebo activates endogenous opioid system?

Answer 14

u-opioid radiotracer was given by I.V.
Pain was administered
Gave placebo and took PET scans
MOR activity correlated w/ reduction in pain

Question 15

Example of how placebo activates dopaminergic circuit?

Answer 15

Thermal stimulus to give pain
Placebo and Lidocaine given topically
PET scan tracks dopamine radiotracer
Change in dopaminergic activity correlated w/ placebo administration

Question 16

Morphine + saline in mice : what response?

What about morphine + naloxone?

Answer 16

Placebo effect

Blocking of placebo effect

Question 17

Aspirin (non-opioid) + saline : what response?

What about aspirin + naloxone?

Answer 17

Placebo effect

Placebo effect (no decrease by introducing placebo blocker)

Question 18

What is nocebo?

Answer 18

Info stating that procedure will be painful leads to increased pain response

Question 19

Example of psychological induction of pain?

Answer 19

Placed electrodes on peoples heads
Told them there would be an electric current that passes them
Headaches were reported

Question 20

Nocebo involves release of what?

What antagonist blocks this?

Answer 20

Cholecystokinin

Proglumide

Question 21

When blocking cholecystokinin with proglumide, what is the response in hidden injection vs. open injection?

Answer 21

Hidden : no changes in pain

Open : Pain increases when given saline but proglumide decreases it