Placebos and the interrelationship among beliefs, behaviour, and health Roland Tisljár Ph.D. Institute of Behavioural Sciences [email protected] Reading Ogden, J. (2007). Health Psychology. A textbook. McGraw-Hill – Chapter 13: Placebos What is placebo • Inert substances that cause symptom relief • Substances that cause changes in a symptom not directly attributable to specific or real pharmacological actions of a drug or operation • Any therapy that is deliberately used for its non-specific psychological or physiological effects History of inert treatments Faith healers ‚Medicines’ without any apparent medical (active) properties Modern day placebos • Multitude of effects – Increase performance on a cognitive test (e.g. Ross and Buckalew, 1983) – Effective in reducing anxiety (e.g. Downing and Rickels, 1983) – Have some affect on a whole series of areas • Allergies, asthma, cancer, diabetes, enuresis, epilepsy, multiple sclerosis, insomnia, ulcers, obesity, acne, smoking, and dementia – One of the most studied areas is pain • Subjective and objective pain reduction Placebo theories • Non-interactive – Individual characteristics – Characteristics of the treatment – Characteristics of the health professional • Interactive – The process involved in the interactions between patients, the treatment and the health professionals Non-interactive theories • Characteristics of the individual – Emotional dependency, extroversion, neurosis, being highly suggestible, introverted – Little evidence to support consistent traits • Characteristics of the treatment – If a treatment is perceived as serious – the effect will be greater • Surgery > injection , two pills > one pill, larger pill > smaller pill • Problems – Ignore the interaction – Assume these factors exist in isolation • Can be examined independently of each other Possible mechanisms of interactive theories • Experimenter bias • e.g. Gracely et al. (1985) – interaction between the doctor and the patient – The experimenter is capable of communicating their expectations to the subjects • Who respond in accordance with this expectations • Patient expectations – The patients expect to get better • Any changes that they experience are attributed to the drugs they have taken • Reporting error • Misattribution of symptom changes to placebo – By the patient and/or by the doctor – Problems • Not all reported symptoms are positive • Objective changes in heart rate, blood pressure Possible mechanisms of interactive theories • Conditioning effect – Patients associate certain factors with recovery and an improvement in their symptoms • e.g. presence of doctors, white coat, pills, injections, surgery • A placebo drug is more effective in a hospital setting when given by a doctor • Anxiety reduction – Placebos decrease anxiety , thus helping the patient to recover – GCT of pain – close the gate and reduce pain – There are many other effects of placebos besides pain reduction (!) The central role of patient expectations All theories of placebo involve the patient expecting to get better Cognitive dissonance theory of placebo (Totman, 1976, 1987) • Attempted to remove patient expectations from the placebo equation – Emphasized justification and dissonance • All of these treatments required investment by the individual – Money, dedication, pain, time, inconvenience – e.g. If medically inactive drugs were freely avaliable they would not be effective Cognitive dissonance theory of placebo (Totman, 1976, 1987) • The effect of investment – two processes: 1) The individual needs to justify their behaviour 2) The individual needs to see themselves as rational and in control – If these two factos are in line with each other – „I spent money on treatment and it worked.” • Low dissonance – If there is a conflict between these two factors – „I spent money on treatment and I do not feel any better” • High dissonance – High/low justification results in low/high guilt and dissonance (!) Cognitive dissonance theory of placebo (Totman, 1976, 1987) • For a placebo effect to occur, the individual does not require an expectation that they will get better – But a need to find justification for their behaviour and a state of cognitive dissonance to set this up Support for cognitive dissonance theory • It can explain all placebo effect, not just pain • It does not require patient expectations, but choice. – This helps to explain those instances where the individual does not appear to expect to get better • It suggests that the individual needs commitment to the medical procedure – Which explains why the individual may need to show some investment (e.g. pain, time, money) to get better – This can explain some of the proposed effects of treatment characteristics, individual characteristics and therapist characteristics. The role of placebo effects in health psychology • Health beliefs • e.g. pill, herbal tea • Conditioning effect, reporting error, misattribution process – Direct effect – physiological change; indirect effect – behavioural change • Illness cognitions – Long lasting disease, medical cause, lifestyle cause • Health professionals health beliefs – The doctor may need to believe in an intervention for it to have an effect The role of placebo effects in health psychology • Stress – Placebos may function by reducing any stress caused by illness – The belief that an individual has taken control of their illness (perceived control) may reduce the stress response • Pain – Pain reduction may be mediated either • By physiological changes (opiate release) • By anxiety reduction – Gate control theory of pain • Previous experience and expectation also implicated in pain reduction Reference • Gracely, R., Dubner, R., Deeter, W., & Wolskee, P. (1985). Clinicians’ expectations influence placebo analgesia. The Lancet, 325(8419), 43.
© Copyright 2024