placebo Flashcards
what is a placebo?
-A placebo is a substance or treatment that has no therapeutic effect, often used in medical research to serve as a control in experiments.
what can placebos help researchers with?
-helps researchers assess the true effectiveness of a treatment by comparing the outcomes of the group receiving the active treatment with the receiving the placebo
what is a randomised controlled trial?
-an experiment in which 2 or more interventions are compared by being randomly allocated to participants
what is a randomised placebo controlled trial?
-an inactive substance or procedure administered to a participant
-placebos are used in clinical trials to blind people in their treatment allocation
-placebos should be indistinguishable from the active intervention to ensue adequate blinding
what is a randomised double blind placebo controlled trial?
-blinding is the process of preventing those involved in a trial from knowing which comparison group a particular participant belongs to
-double blind - both clinician and participant are prevented from knowing
what is a typical example of a placebo?
- saline - control
-morphone - experiment
for pain relief experiments
what are the effects of a placebo in an experiment?
-physiological status
-behavioural response
-subjective experience
-can mimic most drug groups eg withdrawal symptoms , dependency etc
what % of patients will respond to placebos according to the WHO?
-35%
describe the non interactive theory of how placebos work - patient characteristics
-placebos work independently of any direct interaction with the body’s physiological processes. Instead, it emphasizes the role of psychological and cognitive factors in producing therapeutic effects
Describe non interactive theories - treatment characteristics - how placebos work?
-a theory that emphasises the psychological factors rather than direct physiological interactions between the placebo and body
- eg more pills better than fewer, large pills better than small pills, colour of pills, brand names more effective than generic etc
- colour and size of pills can influence the patients perception of treatments effectiveness
Describe the non interactive theories of how placebo works - characteristics of the health professional
-the higher the professional status of the health care provider, the greater the placebo effect
-the more enthusiasm for the treatment by the HCP and the greater the status of the treatment in their opinion, the greater the placebo effect
what are the problems with non interactive theories?
-examine only the patient, treatment or professional and ignores interactions
-assumes these factors exist in isolation and can be examined independently of each other
describe the interactive theory of how placebo works - experimenter Bias
- the impact that the experimenters expectations have on the outcome of the study
-eg patients who were given treatment by doctors who believed the patient had a chance of receiving analgesic (but unknowingly gave the placebo), showed a decrease in pain
describe the interactive theory of how placebos work - reporting errors
- interactive theories of how placebos work proposes that placebos may have a physiological effects that interact with the body’s systems and contribute to their observed effects
-participants in trials or studies might inaccurately report their experiences, or outcomes
describe the interactive theory of how placebos work - learning theory
- suggests placebo response involves not only physiological factors but also a conditioned physiological response
-ie the body can learn to respond to cues associated with treatment, even if the treatment itself is lacking/not capable of producing an effect
