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Relation
Bartels D, van Laarhoven A, Stroo M, et al. Minimizing nocebo effects by conditioning with verbal suggestions: a randomized clinical trial in healthy people.Plus one. 2017;12(9):e0182959.
Objective
To find out whether nocebo effects can be reduced by inducing positive expectancies through electrical and histamine itch stimuli.
Draft
Randomized, controlled, multi-arm, single-blind, parallel-group study
Participant
One hundred and twenty-nine participants of Dutch nationality aged 18 years and over with a mean age of 20.25 ± 2.46 years; 78.7% were women. Exclusion criteria were severe physical morbidity, psychiatric illness, chronic itching or pain complaints, histamine hypersensitivity, regular use of prescription medications in the last 3 months, use of cardiac pacemakers, and color blindness.
Study parameters assessed
Effects of conditioning, counterconditioning and verbal suggestion on nocebo effects of electrical and histamine itch; Influence of psychological characteristics on nocebo effects.
Primary outcome measures
degree of itching reported verbally by participants; psychological characteristics/personality characteristics assessed through self-report questionnaires.
Key insights
Nocebo effects were significantly smaller in the group with positive expectancy induction and even vice versa. Psychological characteristics of the participants had no influence on the results.
Study Restrictions
The study included only healthy volunteers, used only a single session to test reversal of the nocebo effect, had a small study population, and included mostly women.
Practice implications
Nocebo effects are undesirable effects of treatments that are triggered by patients' negative expectations. It is a well-known phenomenon from randomized clinical trials: patients in the placebo group may experience not only the benefits (placebo effect) but also the same treatment side effects as patients in the groups receiving active treatment.1Negative expectations can also impact patients receiving active treatment: patients may not receive the pain relief they expected.2
Nocebo effects can affect a wide range of symptoms, including pain perception, fatigue, nausea, allergic symptoms, and itching. Therefore, knowing how to modify nocebo effects can be a very useful clinical tool.
As clinicians, we have a responsibility to inform our patients of possible side effects, however informed consent may inadvertently lead to negative expectations regarding the proposed treatment intervention.
Nocebo and placebo effects have been extensively studied. Two expectation induction methods are often used in psychology: verbal suggestion and conditioning. Verbal suggestion provides oral or written information about possible benefits and side effects. Conditioning uses an independent neutral stimulus (e.g., color or tone) coupled with an active stimulus (e.g., induction of pain or itch). Over time, a coupled neutral stimulus (seeing a particular color or hearing the sound) can lead to an increased perception of pain or itching, even in the absence of the active stimulus. The present study used both verbal suggestion and conditioning procedures.
The results of the study showed that nocebo effects can be weakened or even reversed by positive expectancy induction. This is an important clinical finding because many patients come to their providers with often negative expectations about how they might respond to treatments. Understanding the sources of patient expectations can help physicians adhere to their treatment plans and, in turn, can improve patient outcomes. These sources include consent forms, previous patient experiences, pre-existing medical conditions, and non-clinical influences from media and friends.3.4
It is interesting that psychological characteristics of the participants in this study did not influence the results. Another study came to a similar conclusion: personality factors (anxiety, fear) had no direct influence on the level of pain expectancy.5A systematic review of the literature on the nocebo effect showed that people's expectations mainly influenced the placebo response,6This places greater emphasis on the role of the healthcare provider in influencing expectations and nocebo and placebo effects.
Thedocere(Doctor as teacher) principle is at the heart of naturopathic practice. We try to educate our patients and also help them take responsibility for their health. As clinicians, we have a responsibility to inform our patients of possible side effects, however informed consent may inadvertently lead to negative expectations regarding the proposed treatment intervention.
How do we effectively provide informed consent?
Research suggests that the way we provide information to our patients makes a difference. In a study by Howe et al. from 2017, positive expectations (placebo effect) were increased when providers were warm and confident.7
Other studies have shown that an authentic communication style that provides appropriate information, feedback, and assessment of patients' fears, concerns, and prescriptions helps minimize nocebo effects of medications.8.9Explaining procedures and interventions in simple language and educating the patient can protect against unwanted side effects.10-12
Such approaches ultimately lead to improved patient outcomes and therefore highlight the importance of building positive rapport and empowering our patients on their journey to better health.