7: The Psychology of Acupuncture Therapy: Placebo and Nocebo Effects in Acupuncture Pain Management

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CHAPTER 7 The Psychology of Acupuncture Therapy: Placebo and Nocebo Effects in Acupuncture Pain Management

INTRODUCTION

Pain, especially chronic pain, results in psychological and physical dysfunction. The expression of pain is a personal characteristic and is influenced not only by abnormal neurophysiologic processes, as discussed in previous chapters, but also by environmental and cultural factors, as well as psychological aspects such as personal experiences, learning, beliefs, and expectations related to the pain and its treatment. All these factors are woven together to form the individual psychological characteristics of a pain patient, and have a significant influence on the efficacy of treatment. In addition, practitioner-patient interactions can exert powerful positive or negative effects on the outcome of treatment.

Once the pain impulses from the peripheral sensory receptors reach the neural networks of the brain, what happens is no longer a purely sensory neurophysiologic mechanism. The perception becomes a complex cognition of the sensory information from the injured tissue, and the processing cannot be independent of the patient’s unique and individual psychological background. Here the pain perception enters a higher level of the hierarchy of biological organization: the psychological. If acute pain is still an element at the neurophysiologic level, chronic pain has been incorporated into the psychological organization. Thus patients with chronic pain show special psychological characteristics in their pain symptoms, in the areas of pain perception, emotion, cognition, expectancy, assigning meaning, and decision making.

Interactions between the factors of neurophysiology and cognitive psychology can produce positive placebo effects or negative nocebo effects. If the interaction favors self-healing, the patient experiences positive placebo effects. If the interaction promotes an internal environment of self-destruction, negative effects occur. Changes in pain over time reflect complex interactions between physiologic processes and psychological syntheses and environmental factors.

A pain patient views his or her pain as a personal experience. The quality and intensity of this experience are influenced by the patient’s unique history, by the meaning he or she gives to the pain-producing situation, and by his or her state of mind at the moment. All these factors modify the actual patterns of pain impulses that ascend from the body to the brain and travel within the brain itself. In this way pain becomes a function of the whole person, including his or her current thoughts and fears as well as hopes for the future.

The same injury can have different effects on different people or even on the same person at different times. Psychological variables may intervene between the stimulus and the perception of pain and can produce different expressions of the pain and a different response to the same medical treatment.

For decades pain professionals have been puzzled by the phenomena of placebo and nocebo effects. In fact these effects are expressions of self-healing or self-destruction that result from interactions between neurophysiology and cognitive psychology. In some patients, both placebo and nocebo effects affect application of every medical modality—drugs, surgery, psychotherapy, acupuncture, physical therapy, biofeedback, manipulation, and massage—in every treatment. Thus these effects are inevitable processes that must be taken into account in every field of medical practice. If the psychological condition of the patient and the mechanism of placebo and nocebo effects are properly understood, the practitioner and the patient can work together to exploit these factors for better pain relief.

OVERVIEW OF THE PSYCHOLOGICAL ASPECTS OF PAIN

The study of the psychology of pain is a rapidly growing field that has developed from behavioral and cognitive psychology. Its fundamental assumptions, although still neuroscientifically based, differ markedly from those of medical disciplines that are based on neurophysiology, such as neurology, psychiatry, and anesthesiology. Neurophysiology is concerned with biological organization and the chemical and physical laws that relate to the structure and function of the nervous system, whereas psychology is a complex of physiologic, cognitive, emotional, and social factors.

Cognition is a self-organizing process that gives coherence to an individual’s life and sense of self, extending across various external settings and through long periods of time.¹ Cognition, for our immediate purposes, consists of the perception of events in the internal (bodily) and external environments, along with the higher-order rational processes of reasoning and decision making. An intensive dialogue between neurophysiology and cognitive psychology is needed to achieve the level of integration that the study of pain management requires, and such an integration will be a path toward better pain management.

Clearly pain is both an important mechanism of biological protection and an aversive psychological experience toward tissue trauma, inflammation, or disease. The following section briefly describes the psychological processes of patients with chronic pain.

Attention

Attention refers to the selective filtering of information from the internal and external environments.¹ A pain patient cannot concentrate his or her attention on normal work and the ordinary routines of life because the pain frequently or constantly intrudes on awareness.

Pain diminishes when attention is intentionally directed toward other events, such as exciting games, books, or films. Distraction of attention, however, is effective only if the pain is steady or increasing in intensity at a slow rate.

Imagery

Our sensory information always creates some sort of image; for example, thinking about a family member may draw the visual image of this person from the memory. Listening to an old melody may bring back an image of a past event. Awareness of pain is one of many types of psychological image that recall for us a kind of aversive experience associated with bodily injury, trauma, or inflammation. Pain as a personal image can be described as a mental representation of the actual sensory activity associated with an injurious external event.²

Expectation

A patient with acute pain may expect the pain simply to go away. A patient with chronic pain gradually becomes hypervigilant for pain and will try to determine whether the pain will worsen, whether it might be associated with some sort of tumor, or perhaps whether the pain is the inevitable result of an inherited genetic disposition. Positive expectation helps the patient respond to medical treatment, whereas negative expectation can induce psychological disorganization and physiologic self-destruction.

Meaning

Most pain patients attempt to attribute their pain to some physical cause, such as rheumatoid arthritis, or speculate about the origin of the tissue trauma and its effect on their immediate and long-range well-being. In some cases this search for a physical cause is difficult or impossible because medical enquiry is unable to identify it. Some patients develop a negative attitude toward personal relationships during this process of seeking the meaning of their pain because they believe that they are “victims.” This negative attitude impedes a patient’s ability to respond to medical treatment and rehabilitation.

If the cause of the pain can be determined, it will influence pain perception and the effectiveness of treatment. For example, a stomach pain may become persistent if the sufferer learns that stomach cancer occurs often in his or her family history; if medical examination excludes the possibility of cancer, the stomach pain may soon stop.

Sensory and Emotional Disturbances as Causes of Anxiety

Pain feels unpleasant, causes fatigue, impairs sleep, interferes with memory, distracts concentration, and disrupts organized action and thought. Chronic pain often becomes the theme around which the patient organizes thinking and action. Chronic pain patients may preferentially recall negative ideas and feelings. Pain can interfere with a person’s ability to see clearly and evaluate his or her situation and the factors that may be causing stress. The results are anxiety, depression, irritability, social withdrawal, and a tendency to expect the worst. All these psychological behaviors increase the intensity of the perceived pain.

Schemata

A schema is a normally unconscious pattern of concepts, assumptions, images, affects, and associations that reflects a person’s experiences and influences his or her perception of the present and expectations for the future.³ Thinking of a university brings a host of associations for those who studied in a university environment: the campus, buildings, young students, professors, and laboratories, for example. This schema is formed by activating a learned network of associations. It does not bring to mind the focused image of a particular teacher in a particular class; rather, it is a nonspecific frame of reference that the brain has collected from many aspects of the personal background.

When thinking about pain, the patient activates a complex schema that involves past pain experiences and medical history, present fear, the possible meaning of the pain, the social consequences of pain, future expectations, and more. This pain schema definitely promotes interaction between cognition and sensory pain signals.

The idea of the schema explains how the human brain can generate its own patterns of awareness and imagery from past experiences. The schema can be retrieved selectively from the memory, modified by the new experience, and put back into storage. This process of schema formation constantly builds and remodels one’s view of the world. Therefore pain is no longer a passive experience of tissue trauma; rather, it becomes a complex organization that involves multiple dimensions of cognitive psychology.

Most doctors view a patient’s description of pain as directly reflecting a sensory experience that provides an important basis for diagnosis. This view is usually accurate when dealing with acute pain. In the case of chronic pain, it is more helpful to view it as a cognitive schema that involves multiple determinants and complex patterns of association. Thus the treatment of chronic pain requires the practitioner to understand not only the neurophysiologic cause of the symptoms but also the psychological associations, such as past experiences, present circumstances, and expectations for the future.

Some Pain Behaviors Seen in Acupuncture Clinics

A patient with pain who is seeking help in the form of acupuncture therapy comes to the clinic as an individual with a unique background and psychological organization; so his or her symptoms become individualized. Each patient presents a different picture of pain. To make the best treatment decision, a practitioner should understand both the neurophysiological basis and the psychological aspects of the pain presented by each patient.

Behavior 1

We learn early in life that after an injury, such as broken skin on the knee, the pain will persist for a couple of days. A child may cry to attract attention and may solicit help after hurting a knee; he or she feels better after the parents offer attention and help. This situation shows that pain can be considered unbearable when help is unavailable, but it diminishes or vanishes when relief is at hand.

Many patients suffer from pain for several days but feel better on the day before they go to the office for treatment. The practitioner should understand that this remission can be a real sign of the beginning of natural healing, but it also can be a temporary relief obscured by psychological factors. Complete treatment should still be administered.

Behavior 2

After one or two treatments, the patient usually feels much better and may regard the result of treatments as “miracles.” Acupuncture sometimes provides fast pain relief, especially in healthy patients who are experiencing acute symptoms (mostly group A patients, see Chapter 6). If this type of “miracle” appears in patients suffering from chronic pain, the practitioner should not be overly optimistic. Chronic pain represents a long-term pathologic change of tissues, such as sensitization of neurons in the spinal cord, and thus for chronic pain there is no quick fix. The “miracle” can be enhanced by psychological elements, such as expectation, strong personal willpower, distraction, and social factors such as family support.

Often a patient with chronic pain has tried many other modalities and failed to get significant results. Acupuncture therapy is new, is “mystical,” and may be positively introduced to the patient through the media, articles, or friends. Often the first treatment produces positive effects such as a good night’s sleep, which the patient may not have had for a while. All these factors arouse in the patient great expectations related to acupuncture treatment. In a case like this, however, the patient may soon feel that the old pain is returning, and therefore that the efficacy of acupuncture is decreasing.

Acupuncture is effective in relieving pain sensation, but healing takes time. The practitioner should understand the true nature of the healing process and work to prevent drastic psychological fluctuations so that the patient’s expectations will be realistic.

A comparable situation is when a new medication is much more effective than the existing ones because it has just come to the market and both doctors and patients are overly enthusiastic about it. After a while, the perceived efficacy of the new drug declines and its real efficacy can then be more objectively evaluated.

Behavior 3

The blood pressure of some patients sometimes increases when measured in a physician’s office. The perceived intensity of pain may increase in the presence of a physician or spouse. This is often seen in patients who have other significant stressors and problem areas in their lives.

If a patient is suspected to belong to this category, another modality, such as psychotherapy, is advised. Recognition that psychological processes influence pain is important for the development of psychological techniques to fight pain.

Importance of Pretreatment Education

Pretreatment education is important during acupuncture therapy. It helps patients to cooperate with the practitioner and thus get more effective treatment.

Simply giving patients information about their pain tends to make them focus on the discomforting aspects of the experience, and their pain is magnified rather than reduced. When patients are taught skills to cope with their pain, such as relaxation, self-treatment, or distraction strategies, they feel that they have some control over the pain and therefore it is felt as less severe.

Most patients expect passively that the practitioner can completely or partially solve their problems and that they will regain their health from the treatment that he or she provides, but active participation of the patient is far better than passive treatment alone.

There is no quick solution to chronic pain. The process of battling it is not a straight line: there are ups and downs. During treatment the pain may become more intense for a short time if the patient is a strong responder. This is good sign, showing that the patient may be healed faster, but the reaction may frighten the patient to the point of stopping treatment. Sometimes, in the case of weaker or older patients, treatment may be followed by more pain or fatigue for 1 or 2 days. Practitioners have to explain to patients that there may be a flare-up reaction to the needling. They should suggest where such pain might arise, how severe it might be, and how long it might last, and they should reassure the patient that such pain is normal after a needling treatment, and that there are steps that can be taken if it happens (e.g., the practitioner can put one or two needles in a painful area to relieve the pain or show a patient how to relax by using breathing and other relaxation strategies). Patients who receive these instructions come to believe that they have better control of the pain, and so will have less anxiety and more confidence to continue treatments. This process is a good psychological preparation and thus reduces the uncertainty and anxiety associated with both the pain and the treatment. It is essential to provide the patient with the knowledge and skills to cope with the pain and anxiety.

The Patient’s Personality

The perception of pain and outcome of the treatment are profoundly influenced by the patient’s personality. Anxiety, neurosis, or a predisposition to becoming overemotional in daily life may greatly impede the effectiveness of healing.

Patients who expect complications and problems (“catastrophizers”) experience more pain. On the other hand, people who have a predisposition to successfully manage life’s stresses tend to use any available strategy—and invent their own when necessary—to manage specific threats to their psychological equilibrium. In the case of the catastrophizer a successful outcome will require the practitioner to call on appropriate techniques and skills.

PLACEBO OR NOCEBO EFFECTS: PSYCHOLOGICALLY INDUCED SELF-HEALING OR SELF-DESTRUCTIVENESS

Biological survival requires the interaction of both physiologic homeostasis and psychological integrity, and the phenomenon of self-healing is a vital factor for survival. Without self-healing, no biological entity can recover from even a minor injury. In fact, recovery and rehabilitation after all medical procedures, especially those of allopathic medicine such as surgery and drugs, depend on the self-healing capability of the individual. This varies from one person to another, which is a reason why any medical modality, including acupuncture, may produce varying results when used for the same pathophysiologic disorder. When we understand the trigger mechanism and the role of self-healing in biological survival, the placebo and nocebo phenomena are no longer mysterious.

Currently placebo is defined as “an intervention that is designed to simulate medical therapy but is not believed to be a specific therapy for the target condition,” or “an inefficacious treatment believed efficacious at the time of use.” The placebo effect is also described as “a change in a patient’s illness attributable to the symbolic import of a treatment rather than its specific pharmacologic or physiologic properties.”⁴ A study showed that about 35% of postoperative patients reported marked pain relief after being given a placebo.⁵ This is a strikingly high proportion because morphine, even in large doses, relieves severe pain in only about 70% of patients.

The nocebo effect has been defined as “the causation of sickness (or death) by expectations of sickness (or death) and by associated emotional states.”⁶

Placebo and nocebo effects can be found in every treatment and in every modality, whether surgery, drug, acupuncture, psychotherapy, chiropractic manipulation, physical therapy, or massage. An understanding of placebo and nocebo effects can help practitioners improve the efficacy of their treatments and patient satisfaction.

Thus the outcome of acupuncture treatment depends on the following:

1. The patient’s physiologic condition, including health status and the severity of symptoms

2. The use of proper treatment methods by the practitioner

3. Psychological interactions between the practitioner and patient that might induce placebo or nocebo effects (Box 7-1)

Box 7-1 Factors that Influence Acupuncture Efficacy

1. Self-healing potential of patients (better and faster results can be achieved in healthier patients. Healthier patients maintain better self-healing potential).

2. Severity of symptoms (better and faster results can be achieved in patients with less severe symptoms. Less severe symptoms are more healable or reversible).

3. Specific acupuncture effects (selection of the most effective acupoints especially SAs and correct needling technique such as proper depth of the needling).

4. Placebo and nocebo effects (psychological interactions between the practitioner and patient).

Placebo

When a drug or medical procedure is referred to as a placebo, there is an implicit negative connotation. This is a misconception that should be reevaluated. Of course the placebo effect should be filtered out when evaluating a new drug or medical procedure, but it is an indispensable part of clinical practice, and every practitioner should understand and use it to benefit those patients who are placebo responders. It is unfortunate that this misunderstanding of the placebo effect is particularly prevalent with respect to acupuncture. In the following section, we examine some placebo studies and explain the mechanism underlying each case.

Case 1: “Sham” Transcutaneous Electrical Nerve Stimulation Therapy

Despite the chronic nature of their pain (an average duration of 4 years), patients with back pain showed improvement in measurements of pain severity, pain frequency, and ability to function. On average the scores improved by 20% to 40% after sham (meaning in this case “unplugged”) transcutaneous electrical nerve stimulation (TENS) plus hot packs.⁷

Case 2: Mystery of the Drug Placebo Effect

Drs. Ronald Melzack and Patrick D. Wall cited a placebo case in their book The Challenge of Pain⁸:

A surprising recent discovery about placebos is that their effectiveness is always about 50% of that of the drug with which they are being compared, even in double-blind experiments.⁹ That is, if the drug is a mild analgesic such as aspirin, then the pain relief produced by the placebo is half that of the aspirin. If it is a powerful drug such as morphine, the placebo has greater pain-relieving properties, again about 50% of that of morphine. How is this possible?

Case 3: “Sham” Surgery

One classic double-blind, randomized study ¹⁰ showed substantial and sustained improvement in angina pectoris after sham surgery (skin incision alone). In this study, 6 months after the operation, 63% of genuinely operated patients and 56% of falsely operated patients had substantial improvement. Benefits were not limited to decreased pain; they also included a reduction in drug use and increased tolerance of exercise.

In other more recent placebo experiments involving the effect of “sham” surgeries on lower back pain and osteoarthritis of the knee, the results showed exactly the same pattern as in this classic experiment.

Case 4: “Sham” Acupuncture

In classic acupuncture practice it is believed that “sham” acupoints cannot be effective. However, one study that used acupuncture for chronic pain concluded that needling sham points seemed to work for 33% to 50% of patients, whereas true points were effective in about 55% to 85% of cases. There was no statistical significance between the results for true and sham acupoints.¹¹ The same study found another puzzle, that although sham acupuncture works in 33% to 50% of patients with chronic pain, it does not work at all in cases of acute laboratory-induced pain.

Of these four examples, only case 2 represents a “pure” placebo effect. The other three cases show the effects of specific treatments but it is a misinterpretation to describe them as placebo effects.

Analysis and explanation of these four placebo cases are provided in the next section.

Mechanism of the Placebo Effect

The remarkably powerful effect of a placebo in no way implies that a patient who responds to a placebo does not have a real medical problem. In Chapter 6 we discussed quantitative evaluation of patients. Based on the number of tender acupoints, we classified patients into four groups:

Group A: 28% of patients. Pain can be eliminated with an average of 4 treatment sessions. Usually this group of patients will respond immediately to any medical intervention, including over-the-counter medications or massage.

Group B: 34% of patients. Pain can be relieved for about 5 months after 8 to16 treatment sessions (average of about 8 treatments).

Group C: 30% of patients. Pain can be reduced for about 5 months after 16 to 32 treatment sessions (average of about 12 to 16 treatments).

Group D: 8% of patients. Very weak or no response to acupuncture treatments.

The number of tender acupoints in the body is the result of the interaction between physiologic homeostasis and psychological integrity. These classifications indicate that patients have different healing potential and thus respond to treatment differently. Because placebo responders show some improvement, it is a sign that there is self-healing, regardless of whether it is temporary or longer lasting. This finding clearly indicates that self-healing could be achieved without any real intervention from outside. Placebo responders are most likely to belong to group A, B, or C.

In Case 1 we saw that 20% to 40% of patients responded to sham TENS plus hot packs. Clinical evidence shows that the application of hot packs alone does reduce pain in some patients, so it is not a placebo but stimulates self-healing, especially in group A and some group B patients.

Case 2 is seemingly puzzling; the placebo response rate is 50% that of either aspirin or morphine. The explanation is simple. Placebo responders will respond to placebo pills because their self-healing potential is capable of being activated psychologically without any medications, regardless of what drugs are used as control—aspirin, morphine, or others.

Case 3 is a comparison between true surgery and sham surgery. The results are not difficult to understand if one is familiar with acupuncture therapy. In China acupuncture is traditionally used with some success to treat cardiovascular problems, including angina pectoris, high blood pressure, and stroke. If the pathologic damage of angina pectoris is slight or mild, the stimulation of needling can relax the smooth muscle and myocardium through the mechanism of cutaneous-visceral reflex. Chinese doctors even invented a special procedure to implant foreign material like sheep gut into acupoint locations, especially on the arms, to prolong the effect of the cutaneous-visceral reflex. The skin incision functions like acupuncture-induced lesions (see Chapter 3). In case 3, therefore, the sham surgery in fact is not sham; rather the body’s self-healing mechanisms respond to stimulation produced by the sham surgery, which, like acupuncture, activates self-healing through stimulating sensory nerves in the area of the surgery. Such a response might equally have followed the use of acupuncture or possibly other modalities as well.

Case 4 is discussed in Chapters 3 and 4. Neurophysiologically there are no sham acupoints because acupuncture therapy is the central nervous system’s (CNS) response to stimulation of sensory nerves, and sensory nerves are distributed all over the human body, except in nails and hair. What are called true acupoints nevertheless provide more significant therapeutic results because they are located on the major nerve trunks. That is why true acupoints provide higher efficacy than sham acupoints.

Laboratory-induced pain is not the same as real clinical pain. Most clinical pain involves sensitized nerves, injured tissues, and inflammation, and as it persists it may change the physiologic homeostasis and the psychological integrity of the patient. Laboratory-induced pain is a type of localized sensory stimulation to which the brain tries constantly and rapidly to adjust. Soon the laboratory-induced pain is ignored by the brain like long exposure to a bad odor in a room. Thus psychologically and physiologically, persons with laboratory-induced pain are no different from pain-free persons. Nevertheless laboratory experiments provide the basic data for understanding pain mechanisms and the principles of pain management.

Now it is clear that the placebo effect is a process of self-healing activated either by psychological suggestion alone or by a combination of psychological suggestion and physiologic stimulation. The effect also occurs in subjects whose self-healing potential is suppressed by psychological factors such as anxiety. We should not exclude the possibility that even some persons with very intractable health problems may experience short-term placebo effects under some psychological conditions.

The placebo effect provides a remarkable form of therapy for some medical problems involving psychological factors that may be partially or completely self-healing. It can be effective not only for pain but also for anxiety and depression and a variety of other medical complaints in which psychological factors play a role. Practitioners may use a placebo to influence cognitive processes as well as to treat injured areas of the body. It is prudent for practitioners to seek to maximize any of the self-healing effects of a placebo that can contribute to the relief of the pain and suffering of their patients.