EBM Flashcards
what is placebo
this is any therapy which has no specific activity for the condition being treated, it has no active ingredient and does not exert any direct physiological effects on cells, tissues or organs. sometimes called dummy treatment.
what are the different types of placebo
sugar pills: biomedical inert placebo
sham ultrasound: while machine is turned off
a fake operation: where incision is made but no operation
sham acupuncture: with blunted needles
all aspects of the treatment environment: including simply having contact with a healthcare professional, but not actually receiving any treatment
what is the placebo effect
any favourable physiological or psychological effect produced by placebos.
change in a symptoms that’s not directly attributable to the drug or treatment under investigation
how can the effect be managed in a clinical trial
the effect can be estimated by excluding the specific effect of the treatment under investigation
where are the effects mostly seen
in subjective outcome mesures
perception of pain is a classic example, where participants in a trial score their perception of pain on a recognised scale.
why is the method of administering placebos important
a greater number of sugar pills can be more effective
different colours and sizes are more effective for certain conditions
if a study on pain requires injection of a treatment, then the saline injection given to the control group is more effective in reducing pain than a sugar pill
how does placebo work?
most likely to work through expectancies. (the idea that we can make ourselves better through our beliefs and expectations)
what are outcome expectancies
beliefs that treatments will have a positive effect on health
what are patient related self efficacy expectancies
beliefs that one can carry out the actions necessary for successful management of a disease
what is conditioning
the idea that we have previously formed associations between all sorts of aspects o previous heath care and positive outcomes
reducing anxiety effects
receiving healthcare can reduce anxiety about potential illness and contact healthcare progressionals can have indirect positive outcomes, especially if associated with these previous experiences.
what are the psychophysiological mechanisms
where psychological states affect physiology e.g the release of endorphins, and endogenous opioids, increased production of dopamine
what are the ethical considerations for placebos in clinical trials
you would have to decide what patients for the control you would use. the alternatives might be either a group on existing treatment one given a placebo, but not any other treatment. there are ethical considerations of denying a known treatment for the placebo group
what is the patient information in a clinical trial
you must also ensure that the patients and participants are fully informed about the implications of participating In a clinical trial, which includes a placebo group so you must think about a risk benefit analysis of placebo effects
what is the placebo responders element in clinical trials
as indicated earlier, some participants may have a higher response to placebos than others and could be a cofounding factor
what is a placebo ‘washout’
placebo administered for a specific period before commencing the study.
what are the important implications of a placebo washout
if it is possible for participants to be taken off there existing treatments before commencing the study,. the washout enables their effects to be removed before beginning the investigation
placebo responders i.e those with a high response to placebos, the washout will enable you to identity them as you may wish to exclude them from your investigation
compliance, it also enables you to confirm if participants comply with instruction regarding medications, before starting the study
what are CAMS
- therapies or interventions that are non-conventional, non-standard
non prescription and non surgical
can either be pharmacological or non pharmacological
may involve drugs, but they can be exercise regimes, participation in self help groups, use of specific procedures like acupuncture, chiropractic
what are we referring to when we say complementary
this refers to interventions that are used together with conventional medicine (so complementary is used as well as standard treatment)
what is the best way to investigate complementary therapies
randomised controlled trials
why are randomised control trials used
a well designed study could be applied to homeopathy - and quite a few have been done. consistently they show homeopathy to have no effect beyond placebo. this does not mean that taking homeopathic remedies have no effect, they may be beneficial, but no more so than if a placebo was used instead.
some examples of CAMS
acupuncture
tai chi -ancient Chinese exercise system
chiropractice for migraine
herbal remedies for pain in young athletes
do patients with Parkinson’s use CAMs
around 60% of them do. in some way or another, their effect might be related to dopa release, the effectiveness of a CAM, like that of a placebo is associated with treatment intensity and invasiveness. although some treatments actually contain Ldopa, others are likely to be mediated through dopamine release in the reward system pathway, related to their anticipated benefits. In Parkinson’s, CAMs that are no different to placebos need not necessarily be discounted, especially if there are minimal risks associated with their use, they are providing some relief.
what are the problems with CAMS
people who are unwell may be vulnerable and desperate to try something. this can be dangerous if they subscribe to alternative therapies. they might be missing out on more effective treatments
little statutory regulation of complementary and alternative medicine. practitioners usually do not have to be registered in the UK so there I a lower level of legal protection for people who use complementary therapies
complementary therapy may influence the effectiveness of prescribed therapy and lead to complications. for example, iron supplements may reduce absorption of L-dopa, decreasing the effectiveness of the dopaminergic therapy in PD
doctors are often not aware of what complementary therapies are being used
they can be expensive compared to NHS systems
