Patient expectations and the placebo effect
The research issue
For a long time, medicine has regarded adherence to (i.e. compliance with) medical recommendations as important for patient recovery. This might be expressed in simplified forms such as: ‘Take these drugs and you will get better.’ Implicit within this assumption is the belief that an ‘active drug’ is better than a placebo. This is why trials to explore the effectiveness of a drug should compare it with a placebo. But it is possible that simply taking medication (whether active or inert)may also be beneficial if the patient expects to get better. This perspective is in line with the focus on beliefs found within health psychology, and the prediction that positive expectations may result in improvements in health. This paper (Horwitz et al., 1990) presents a reanalysis of the data from a drug trial that explored the effectiveness of beta blockers following a heart attack. The paper asks whether simply adhering to medical recommendations to take pills was beneficial to recovery following a heart attack, regardless of whether the pills taken were active pills or placebo pills.
Design and procedure
The original study included 3837 men and women aged 30 to 69 who were reassessed every three months for an average of 25 months. For this paper, data were analysed from 1082 men in the experimental condition (who had received the beta blocker) and 1094 men in the placebo condition. Follow-up data were analysed for 12 months. Measures were taken of psychosocial factors, adherence and clinical characteristics.
Results and implications
1.Compared to patients with good adherence, those with poor adherence were twice as likely to have died at one year follow-up. This was true for both the experimental group and the control group.
2.Even taking into account psychosocial factors (e.g. stress, depression, smoking, alcohol use, exercise) and clinical factors (e.g. severity of heart attack), this finding was the same.
3.So, regardless of whether the drug was a beta blocker or a placebo, taking it as recommended halved the participants’ .chances of dying over a 12-month period.
These results indicate a strong link between adherence to medical recommendations and mortality, regardless of the type of pill taken. This effect does not appear to be due to psychosocial or clinical factors (for example, the non-adherers did not simply smoke more than the adherers). So doing as the doctor suggests appears to be beneficial to health, but not necessarily because ‘the drugs are good for you’. Instead, the findings indicate that simply by taking (what is believed to be) medication, the patient expects to get better. The authors concluded that ‘perhaps the most provocative explanation for the good effect of good adherence on health is the one most perplexing to clinicians: the role of patient expectancies or self-efficacy’. The researchers suggest that ‘patients who expect treatment to be effective engage in other health practices that lead to improved clinical outcomes’ (Horwitz & Horwitz, 1993). The authors also propose that the power of adherence may not be limited to taking drugs; it may occur with other forms of health intervention such as recommendations for behaviour change.
Horwitz, R.I., Viscoli, C.M., Berkman, L. et al., 1990, ‘Treatment adherence and risk of death after a myocardial infarction’,
Lancet, 336 (8714), 542–5.
The research issue
For a long time, medicine has regarded adherence to (i.e. compliance with) medical recommendations as important for patient recovery. This might be expressed in simplified forms such as: ‘Take these drugs and you will get better.’ Implicit within this assumption is the belief that an ‘active drug’ is better than a placebo. This is why trials to explore the effectiveness of a drug should compare it with a placebo. But it is possible that simply taking medication (whether active or inert)may also be beneficial if the patient expects to get better. This perspective is in line with the focus on beliefs found within health psychology, and the prediction that positive expectations may result in improvements in health. This paper (Horwitz et al., 1990) presents a reanalysis of the data from a drug trial that explored the effectiveness of beta blockers following a heart attack. The paper asks whether simply adhering to medical recommendations to take pills was beneficial to recovery following a heart attack, regardless of whether the pills taken were active pills or placebo pills.
Design and procedure
The original study included 3837 men and women aged 30 to 69 who were reassessed every three months for an average of 25 months. For this paper, data were analysed from 1082 men in the experimental condition (who had received the beta blocker) and 1094 men in the placebo condition. Follow-up data were analysed for 12 months. Measures were taken of psychosocial factors, adherence and clinical characteristics.
Results and implications
1.Compared to patients with good adherence, those with poor adherence were twice as likely to have died at one year follow-up. This was true for both the experimental group and the control group.
2.Even taking into account psychosocial factors (e.g. stress, depression, smoking, alcohol use, exercise) and clinical factors (e.g. severity of heart attack), this finding was the same.
3.So, regardless of whether the drug was a beta blocker or a placebo, taking it as recommended halved the participants’ .chances of dying over a 12-month period.
These results indicate a strong link between adherence to medical recommendations and mortality, regardless of the type of pill taken. This effect does not appear to be due to psychosocial or clinical factors (for example, the non-adherers did not simply smoke more than the adherers). So doing as the doctor suggests appears to be beneficial to health, but not necessarily because ‘the drugs are good for you’. Instead, the findings indicate that simply by taking (what is believed to be) medication, the patient expects to get better. The authors concluded that ‘perhaps the most provocative explanation for the good effect of good adherence on health is the one most perplexing to clinicians: the role of patient expectancies or self-efficacy’. The researchers suggest that ‘patients who expect treatment to be effective engage in other health practices that lead to improved clinical outcomes’ (Horwitz & Horwitz, 1993). The authors also propose that the power of adherence may not be limited to taking drugs; it may occur with other forms of health intervention such as recommendations for behaviour change.
Horwitz, R.I., Viscoli, C.M., Berkman, L. et al., 1990, ‘Treatment adherence and risk of death after a myocardial infarction’,
Lancet, 336 (8714), 542–5.
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