Lecture 18 - Placebo/Nocebo Flashcards
What is the difference between placebo and nocebo effects?
Placebo effects refers to when we have positive health effects from something that was not meant to have any therapeutic benefit, such as a sugar pill.
Nocebo effects refers to the negative experiences or physiological changes that occur when we have negative associations or expectations for a treatment or process.
In an experiment that looked giving an open injection (overt) of pain killer or a hidden injection (covert) what did they find in regards to subjects’ pain levels?
When they openly interrupted the treatment or interrupted the treatment covertly, what did they find happened to subjects’ pain level?
Subjects who were given an open inejction of pain killer experienced their pain levels dropped faster than those who were covertly given a painkiller.
Subjects who saw that their painkiller was being removed/interrupted experienced their pain levels increase faster than those who had their painkiller removed covertly.
This suggests that there are other aspects of our cognition, such as epectations and predictions, that influence our experience of pain.
In an experiment that looked at placebo and Maxalt (a treatment for migraines), what did they find occurred for those who received placebo pills labelled as Maxalt and Maxalt pills labelled as Placebo?
What did they find about open label placebo?
They found that in both cases there was more of a reduction in pain than those who received no treatment, however, there was no significant difference between the two conditions, highlighting the effect of placebo as well as our expectations of placebo on treatment outcomes.
They also found that even open label placebo is better than no treatment.
Has it been found that when the provider has an expectation (for positive or neutral outcomes) for the effectiveness of a painkiller that this influences reduction/or no reduction of pain for patients?
yes.
Is it true that those who respond the strongly to treatment also tend to respond strongly to placebo?
Yes.
Have there been experiments done that find that even when someone observes another person experiencing a negative sensation in response to a stimulus that they themselves then experience a negative/painful sensation in response to that stimulus even when the sensation is not noxious?
Yes.
How does the PAG decrease pain response?
Release of endogenous opioids.
Can placebo treatments also reduce emotional pain?
yes.
What areas of the brain are thought to contribute/cause the placebo effect?
The dorsolateral prefrontal cortex (DLPFC) and the periaquaductal grey (PAG).
What chemicals/neurotransmitters are involved in the placebo and nocebo responses?
Opioids, dopamine, cannibinoid, cholecystokinin.
The expectation of positive effect, such as relief from pain, causes the release of endogenous endorphins, which bind to opioid receptors and block the perception of pain.
Is this one of the ways placebo is thought to work in the brain?
Yes.
When subjects are given naloxone (which blocks opioid receptors) do they experience the pain relief associated with placebo?
No. This suggests that the pain relieving effects of placebo involve endorphins and the opioid pathway.
Randomised, double-blind, placebo-controlled trials are the gold standard for clinical trials.
T/F?
True.
How are nocebo effects decreased in clinical settings?
Training practitioners to speak to clients in a way that decreases fear.
