Archive for the ‘Placebo’ Category

Placebo: the Meaning Response

Friday, November 20th, 2009

Understanding which components of the therapeutic encounter are valuable in producing positive responses to a health care intervention is an important responsibility of every health profession. The ability to produce specific treatment effects that intervene directly with the presenting dysfunction or pathology is the conventional aim of health care practice, and maximising these effects is usually viewed as providing optimal care.  Positive responses that are unrelated to these specific effects, or even occurring in the absence of them, are often also present but these are dismissed as the result of placebo effects.

Although the potential for placebo responses is a ubiquitous feature of all health care practices, placebos are usually referred to as irrelevant and unintended side-effects. It is only by subtracting the magnitude of change produced by placebo responses that the ‘real’ value of any treatment may be revealed. When ‘real’ effects are considered an impossible consequence of the intervention, the intervention is designated a sham-or a scam. However, placebo responses often result in very meaningful for changes for the patient, and since meaningful positive change is the primary motivation for seeking care, this must reconciled with the professional responsibility to provide definite therapeutic inputs.

It is now well recognised that placebo effects occur in response to the contextual components of the therapeutic encounter and the patient’s individual interpretation of these. Unless we intend to resurrect Cartesian dualism, placebo effects must be understood as arising from brain effects, i.e. processing within the central nervous system has changed in some way. Therefore, placebo is not something that is ‘administered’. It is a response that emerges from the patient.

The clinical potency of therapeutic responses dependent on the contextual components of therapy is malleable. For example, Ted Kaptchuk’s team have demonstrated that sham acupuncture is associated with significantly greater reduction in pain intensity and symptom severity than placebo pills for repetitive-use arm pain. Culture, social circumstances, personal history, individual predilections and expectations all shape the patient’s interpretation of the significance of the illness experience and that of the particular treatment process. According to Moerman and Jonas, placebo responses occur when the meaning of the illness experience has changed. They have even proposed that the placebo response may be more accurately termed the meaning response.

Meaning is enhanced via story, and the stories we tell patients about their illness and the treatment we prescribe can have a significant effect on the perception of these experiences. A classic example of this was seen in a study by Moseley et al., which demonstrated that teaching patients about the neurophysiological mechanisms responsible for their pain, particularly the tenuous relationship between pain intensity and tissue damage, resulted in immediate improvements in functional performance. The same education has been demonstrated to result in widespread alteration of brain activity characteristic of the pain experience.

Although there is no doubt that any story and subsequent treatment that is consistent with an individual’s expectations and/or is sufficiently convincing as an appropriate intervention will increase the likelihood of meaningful placebo responses, many argue that stories and accompanying treatments that are inconsistent with objective understanding of human function are unhelpful at best and dangerous at worst. Moerman and Jones write,

“by focusing on placebos, we constantly have to address the moral and ethical issues of prescribing inert treatments, of lying, and the like. It seems possible to evade the entire issue by simply avoiding placebos. One cannot, however, avoid meaning while engaging human beings.”

However, giving inert treatments is not identical to using the meaning response therapeutically. One need not give sugar pills. Providing intervention that is both consistent with objective understanding of human health and illness and seeks to enhance the significance of the therapeutic process may maximise positive outcomes without compromising ethical and moral responsibilities.

Placebo responses are not sufficiently potent to resolve all health problems. Conditions that are the most amenable to placebo responses are those associated with psychological distress and sympathetic arousal, e.g. anxiety, depression, hypertension, angina, stress-related immunosuppression, addiction, functional digestive disorders, headaches, and especially, pain. John Medina explains that psychophysical stress responses occur when a negative situation is interpreted as beyond one’s control. Positive changes in the meaning of these experiences may occur when a person:

1. receives an explanation that makes sense to them
2. feels safety in the presence of aid or the expression of care and concern
3. experiences an intervention they expect will resolve the problem as they understand it
4. gains skills and knowledge that allows control or mastery over the experience.

The following list was presented by Walach and Jonas in their paper, Placebo research: The evidence base for harnessing self-healing capacities. These methods have been demonstrated in the medical literature as effective for enhancing placebo responses:

• Use more frequent dosing (or treatment) rather than less frequent dosing (up to a limit).
• Apply therapies in therapeutic settings such as hospitals and clinics.
• Attend to the route of administration.
• Deliver therapies in a warm and caring way.
• Deliver therapies with confidence and in a credible way.
• Determine what treatment your patient believes in or not.
• Be sure you as a therapist believe in the treatment and find it credible.
• Align all beliefs congruently: patient, doctor, family, culture.
• Deliver a benign but frequent conditioned stimulus along with the effective therapy.
• Use the newest and most prominent treatment available.
• Use a well known name brand identified with success.
• Cut or stick the skin or poke into an orifice whenever it is believed important.
• Inform the patient what they can expect.
• Use a light, laser, or electronic device to deliver and track the treatment when possible.
• Incorporate reassurance, relaxation, suggestion, and anxiety reduction methods into the delivery.
• Listen and provide empathy and understanding.

and an easy one for manual therapists…

• Touch the patient.

Check out this great interview with Nicholas Humphrey on contextual therapeutic responses from an evolutionary perspective.

Tags: meaning, pain
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Placebo analgesia is augmented following prior observation of successful treatment

Monday, August 3rd, 2009

It has long been known that psychosocial factors play a crucial role in placebo responses. According to Colloca and Benedetti, no attempt has been made to understand if social observation shapes the placebo analgesic effect. To address this question, they compared placebo analgesia induced through social observation (Group 1) with first-hand experience via a typical conditioning procedure (Group 2) and verbal suggestion alone (Group 3). In Group 1, subjects underwent painful stimuli and placebo treatment after they had observed a demonstrator (actually a simulator) showing analgesic effect when the painful stimuli were paired to a green light. In Group 2, subjects were conditioned according to previous studies, whereby a green light was associated to the surreptitious reduction of stimulus intensity, so as to make them believe that the treatment worked. In Group 3, subjects received painful stimuli and were verbally instructed to expect a benefit from a green light. Pain perception was assessed by means of a Numerical Rating Scale (NRS) ranging from 0=no pain to 10=maximum imaginable pain. Empathy trait and heart rate were also measured.

The researchers found that observing the beneficial effects in the demonstrator induced substantial placebo analgesic responses, which were positively correlated with empathy scores. Moreover, observational social learning produced placebo responses that were similar to those induced by directly experiencing the benefit through the conditioning procedure, whereas verbal suggestions alone produced significantly smaller effects. These findings show that placebo analgesia is finely tuned by social observation and suggest that different forms of learning take part in the placebo phenomenon.

Colloca L, Benedetti F. Placebo analgesia induced by social observational learning. Pain. 2009 Jul;144(1-2):28-34. Epub 2009 Mar 10.

Tags: Featured, pain
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