Placebo

.... Showed that immunosuppression can be conditioned in rats. These findings have been well replicated

Ader & Cohen (1975)

How was PE initially used?

As a control group in clinical trials to test for the effectiveness of new medicine or therapies.

Transactional model of placebo responding

Attempts to explain behaviour by considering the dynamic relationship between a person and their environment. Responsiveness to placebo may be seen when there is a match between an individual's trait-like response system and environmental contingencies.

In steward-Williams and Podd's idea, what shapes the placebo effect?

C.c. is one way of learning that shapes the PE, but verbal information is another shaping source.

Darragh et al., 2014

Contextual factors are known to be centrally important to the PE. The is a utility in considering an interaction between disposition and environment. Transactional model of placebo responding

What did the tests in the coffee experiment test?

Coordination, accuracy, concentration and speed

Reference for personality

Darragh et al, 2014.

Why are psychological processes fundamental in PE?

Determine how and why patients detect interpersonal and contextual cues that lead to PE

Rats were injected with amphetamine. When the syringe was conditioned with the response, even an injection with saline produced behaviour similar to when injected with amphetamine. (source)

Herrnstein, 1962

More recent research on personality and PE?

In combination with environmental factors.

What if C.C. is the source of learning for PE?

It can vary. Sometimes entirely mediated by consciously accessible expectancies, some PE are not mediated by conscious cognition.

What does R-E T not assume?

It does not assume that expectations alone can account for placebo effects, but they do see it as the most important variable involved.

Placebo effect can do what to treatment? Incl. reference

Katchuk, 2014; 2010. affects treatments positively, may function as well as active drug therapies

Extraversion, personality & PE (source)

Kelley et al., 2009 Extraversion only predicted placebo responding when treatment was delivered by a caring and empathetic practitioner.

What is the reference for the coffee experiment?

Kirsch & Weixel, 1988

Response-expectancy theory

Recipients expect certain responses. The placebo elicits a expectation for a particular effect, and the expectation produces that effect. Thus, PE are a subcategory of expectancy effects, and placebos are an expectancy manipulation.

What did the coffee experiment result in?

Significant correlation between beliefs of performance after caffeine and actual performance

Recent sham surgery (source)

Sihvonen et al., 2013 Arthroscopic partial meniscectomy. 146 participants. Randomized double blind. No sig. diff. pre-treatment No sig. diff post treatment 12 month follow up. Sham surgery equally good.

Classical conditioning theory. Give evidence + references

Someone has learned to associate ex. pain relief with a pill or injection. Stewart-Williams & Podd, 2004. Description of c.c. Herrnstein, 1962, Rats & amphetamine Ader & Cohen, 1975, Rats & immunosuppression conditioning

What reference to use when describing R-E T?

Steward-Williams & Podd, 2004

Who argued that both C.C. and Expectancy theory can explain placebo effect rather than either or?

Steward-Williams & Podd, 2004

What to include in intro

The Placebo effect has the potential to improve patient care Much of the research on PE focusses on the neurobiological mechanisms involved. (Levine et al., 1978), analgesia. Psychological processes fundamental.

Why is personality important to PE?

The ability to determine who is responsive to placebo treatment and in what context may facilitate effective treatment design by matching treatment to individual.

How does the expectancy theory explain placebo?

The belief in getting better may result in a reduction in anxiety. Placebo analgesia may lead to decreased self-defeating thoughts and images and a greater frequency of coping mechanisms

Since not all placebo effects are mediated by conscious cognition, the combined model argues that ...

a complete model must include both non-cognitive learning mechanisms such as c.c. as well as conscious expectancies

What personality traits were linked to PE early on in research? But?

depression hypochondriasis, schizoid personality, and neuroticism. They were not able to replicate these findings.

Dispite many studies on te neurobiological effects of placebo, more effort should be put into... Future research tips

developing empirically derived and theoretically complex psychological process models. Non-deceptive, encourage placebo response, identify with more accuracy which factors mediate the PE.

What if verbal information shapes the PE?

it seems reasonable to assume that it is mediated by an expectancy.

What influences does the R-E T not rule out? But?

the influence of the therapeutic relationship, the provider's expectations, or sociocultural factors. However, the effects of these factors are due to their influence on the placebo-deliverer's expectations.