8 - complementary theories and placebo effects Flashcards
define complementary therapies
a group of therapies that share a focus on, or integration of, treatment of mind and spirit as well as body
focus of complementary therapy
symptom relief
prevention
why are many people not confident with the benefits of alternative therapy
there is much less supporting evidence
however this does not mean it is not effective
how might complementary therapy benefit the NHS
pain or discomfort relief for patients
improvement of well-being for patients
may save NHS money
what might prevent the NHS from offering complementary therapies
little/no evidence to suggest that they arent harmful
NHS has limited resources
treatments must be cost-effective
examples of complementary therapy
acupuncture acupressure aromatherapy herbal medicine yoga reiki
definition of placebo effects
treatment effects of remedies that are not understood to have any direct link to the outcome
features of placebo effects
mimic drug effects
mimic drug side effects
powerful
complex interaction between psychological and physiological mechanisms
research evidence that shows that placebos have important effects
van Laarhoven 2015
systematic review of 34 trials of people with chronic itch due to a skin condition e.g. psoriasis
results:
placebo arm significantly decreased itch compared with baseline (1.3 out of 10)
psychological mechanisms of placebo effect
outcome expectancies
classical conditioning
neurobiological mechanisms of placebo effect
opioid mechanisms
non-opioid mechanisms
what factors influence outcome expectancies of treatment
manipulation via verbal cues
mode of treatment delivery (IV, oral, cream)
how does classical conditioning work in the placebo effect
repeated associations between neutral stimulus and an active drug (unconditioned stimulus)
neutral stimulus elicits response characteristic of the unconditioned stimulus
disadvantage of relying on the classical conditioning mechanism
its difficult to exclude any other cognitive components in human trials such as outcome expectancies
opioid mechanisms
underly placebo effect
changes in brain activity can be seen using PET imaging or fMRI similar to opioid changes following placebo administration
role of opioid antagonist naloxone
administered to completely or partly reverse the pain related placebo effects
role of opioid antagonist naloxone
administered to completely or partly reverse the pain related placebo effects
effect of drug type on conditioned response
- whilst conditioning the patient to have a response to a drug, the different drug chosen can elicit different placebo mechanisms
non-opioid mechanisms seen as a placebo response in parkinsons patients
changes in dopamine release in the striatum, basal ganglia and thalamus
decrease in tremors and shaking
non-opioid mechanisms seen as a placebo response in patients with depression
changes in metabolic activity in the brain seen
example and results of research on placebos to treat headaches caused by hypoxia
1 aspirin tablet placebo–> effects seen via inhibition of cyclooxygenase
1 oxygen mask placebo –> effects seen by reduced ventilation and reduced blood alkalosis
result –> larger physiological effects exerted by oxygen mask placebo
evidence that placebo effect is more than psychological
impact of types of outcome expectancies on outcome
conscious expectancies lead to behaviour changes and schematic processing resulting in subjective placebo effects
unconscious outcome expectancies lead to objective physiological placebo effects
impact of placebo effect on beliefs about interventions
when placebo effects are large, they cast doubt on the intervention efficacy and on the proposed mechanism of action of the “real” treatment
people start to think the effect of the drug is wholly due to psychological processes
evidence to suggest there is no difference between giving a drug and a placebo
howick et al 2013
systematic review of 115 studies
found no significant difference between treatment and placebo effects
ernst et al 1995
says that clincial trials should always be double blind
says trials should have 3 arms not just 2
intervention, placebo and no treatment
why is the 3rd arm (control) so important
controls for normal regression towards the mean over time, spontaneous remission, unknown parallel interventions or trial drop-outs
makes sure we know people are only getting better due to the intervention or placebo and not due to other confounding factors
how do you calculate results of the trial using the 3 arm method
treatment effect = intervention arm - placebo arm
placebo effect = placebo arm - no treatment arm
example of an intervention that it very difficult to create a placebo for
cognitive behavioural therapy (CBI)
patient is actively involved in the treatment
example of a 3-arm trial
single-blind RCT for 262 patients with IBS
–> looked at effects of how patients are treated by the clincian
method of 3 arm IBS trial
arm 1 –> validated placebo acupuncture device and supportive patient-clinician relationship (attention, warmth, confidence)
arm 2 –> validated placebo acupuncture device
arm 3 –> no treatment
results of 3 arm IBS trial
adequate relief on validated measure for IBS patients shown by:
62% for arm 1
44% for arm 2
28% for arm 3
shows changes in expectation encouraged by the clinician can significantly effect results
factors involved in strength of placebo effects
treatment characteristics (shape, colour, size of drug) healthcare setting (hospital works better than home) patient characteristics (beliefs, expectations, anxiety levels) HCP characteristics (gender, status, beliefs, job satisfaction) HCP-patient relations (information provision, reassurance, compassion, changing expectations)
who came up with the taxonomy of placebo effects for clinical practice/research
bishop et al 2017
techniques for creating placebo effects in research
creating positive expectancy
reduce negative expectancy
select patients based on treatment history
sham interventions-attention only
how does a clinician create positive expectancy in patients
deliberately and explicitly suggest to patients that the intervention will be negative for them
how does a clinician reduce negative expectancy in patients
deliberately minimise the potentially negative or harmful procedures and characteristics of the treatment
reassure the patient that the treatment is unlikely to be ineffective
which patients would you recruit for a successful placebo study
patients naive to the intervention being tested (check their treatment history)
what does bishop et al 2017 mean by sham intervention-attention only
patients only receive study-specific attention in terms of numbers and visits and time spent with study staff but no additional intervention
why are the results from placebo research studies useful
help to create other treatments that are perhaps more cost effective
provides evidence on how HCPs should interact and communicate with patients to improve patient outcome and adherence to medication
how do HCPs provide cognitive care
HCPs can influence patients’ beliefs and expectations through descriptions of the illness/treatment
how do HCPs provide emotional care
HCPs reduce negative effects by providing empathy, warmth, reassurance and support to patient
evidence that care from HCPs is important for patient outcomes
Di Blasi et al 2001
systematic review of 25 RCTs
25 manipulated cognitive care, 4 manipulated cognitive and emotional care
overall found manipulation of care improved patient outcomes
ethical issues behind placebos
deception of patients is wrong
doing research where we dont know the outcome is risky
patients consenting to placebo surgery (e.g. knee slit) that may have damaging effects
evidence to show that placebos can work without deception
kaptchuk et al 2010 Harvard
IBS patients tested
arm 1: pills presented as placebos, patient told about benefits of the placebo effect
arm 2: no treatment
same patient care maintained throughout
significantly higher mean IBS improvment scores in arm 1
