What is pain and how to deal with pain? - Chapter 16

What does the experience of pain entail?

Pain is not simply the presence or absence of pain stimuli. There are a number of physiological and psychological explanations for why and how we experience pain. People respond differently to acute pain than to chronic pain, so there are different ways of dealing with those two types of pain.

Most people have experienced pain sometimes. Experiencing pain is not pleasant for most people, but it is usually functional. It warns us of damage to the body. The pain causes you to handle that painful area with care. People with a congenital defect that prevents them from experiencing pain usually die at a young age. They do not respond to the symptoms of illness and therefore do not seek help themselves. This condition is known as congenital universal insensitivity to pain (CUIP).

Despite the protective and warning effects of pain, pain is very annoying and sometimes even unbearable if it lasts too long. Sometimes a place still hurts while the tissue is already healed and sometimes people feel pain in limbs that have been amputated. This last phenomenon is called phantom pain.

Types of pain

Acute pain: most people have acute pain that lasts no more than a few minutes, but the definition of acute pain describes pain that lasts for less than three to six months. Most types of acute pain are the result of an injury and therefore usually disappear automatically when the injury has recovered. Acute pain can also be a recurring phenomenon, for example when it comes to the pain of migraine.

Chronic pain: chronic pain is defined as pain that lasts longer than three to six months. Chronic pain often starts as acute pain that does not recover or slowly recovers. Two types of pain can be distinguished in this category:

• A gentle, calm pain: the pain is always about the same.
• Chronic, progressive pain: the pain gets worse over time.

You can also distinguish between the nature of the pain, such as the feeling of the pain itself (stinging, burning, nagging), the severity of the pain (ranging from mild to unbearable) and the pattern (short, long-lasting or recurring).

The prevalence of pain

Chronic pain is more common than most people think. For example, a large-scale study shows that 35 to 51% of the population have experienced some form of chronic pain. Lower back pain is common. Chronic pain is also common in young people between 12 and 19 years. The most common causes are injuries, health problems and sports injuries. Older people suffer more often from chronic pain, but the explanation for this is probably that the health of older people is less good than the health of young people. People with a physically demanding job also reported experiencing chronic pain more often. Divorced people indicated to have (had) pain more often than married people.

The most common places of pain are the back, the abdomen, and the head. Of all the reasons why people visit the doctor, 40% have to do with pain. Most people who go to the doctor with pain complaints also report that the pain limits their freedom of movement and physical possibilities.

Living with pain

Chronic pain has much more effect than just the bad feeling itself. When you have just as much pain and know that it will pass again, it is something completely different than when the pain will always be there. It can prevent people from doing physical and social activities and can make it impossible to carry out their work. The latter can in turn have financial consequences. No wonder that a lot of depression is found in people with chronic pain. The causal direction is not exactly known, people can become depressed by the pain and its consequences, but people can also pay more attention to the pain through depression. It is not unusual that depression causes someone to focus more on physical symptoms. Depression can also make people feel unable to do anything about the pain, so they make no effort to reduce the pain.

However, people with chronic pain can also mention positive consequences:

• Primary gain: when expressing the pain results in the reduction of an unpleasant consequence, for example someone in the family takes over a household task when the sick cannot do it because of the pain.
• Secondary gain: when the pain results in a positive outcome such as sympathy or concern from others.
• Tertiary gain: the feeling of pleasure or satisfaction that someone experiences when he helps someone suffering from chronic pain.

There are two sides to that tertiary profit. In the short term it makes both parties happy. Someone who no longer needs to help in the house is happy that his back pain is not getting worse at the time, and the person taking over the job is probably happy that he can do something for the other. But at some point the positive effect is no longer there. The person who no longer is helping will also miss out on necessary physical exercise and the person who takes over the task will eventually become overloaded if the other person isn't recovering. Moreover, the task transfer becomes normal for both parties over time. The person with pain no longer thinks that he will get out of that task and for the person who has taken over it no longer feels like helping immediately.

Brena and Chapman (1983) described the so-called "five Ds" that result from such an environment:

1. Dramatization of complaints.
2. Disuse through inactivity.
3. Drug misuse (as a result of over-medication as a response to pain behavior).
4. Dependency on others (due to learned helplessness and poor use of personal coping skills).
5. Disability due to inactivity.

How do people communicate pain?

Expression of pain is a form of communication and that is functional. Women during labour get more support when expressing pain, and that increases the chance for survival for mother and child. Communication of pain is especially important in a medical context, because then the patient will get enough pain medication. 

The expression of pain can be deliberate or incidental. Usually, people express there pain through facial expressions. 

What are the biological models of pain?

The simplest theory about pain is that there are pain receptors in the skin and other parts of the body and that, when activated, they cause pain. They send information to the pain center in the brain, which by activation provides the sensory experience of pain. This theory is also called the specificity theory. This theory was first proposed by Epicurus and later described by Descartes.

It was later discovered that people have three types of nerves that respond to pain, heat or cold. Goldscheider added in 1884 that someone only feels pain when a certain threshold value has been exceeded with regard to the stimulation of the pain receptors. With these types of theories, the amount of pain experienced is directly related to physical damage. However, we now know that this is not the case.

There are three important factors that have to do with it:

1. Pain while there are no pain receptors: the best example of this is phantom pain. Phantom pain means that people have sensations that can sometimes be extremely painful, that they feel in limbs that they no longer have. They feel tingling, cramping or stabbing in their leg that is amputated. They usually feel this from a week to half a year after the amputation, but in some cases the pain continues for years. This is more common with amputated arms than with amputated legs. The same effect occurs in people with spinal cord damage and people with paralysis.
2. Pain receptors that do not transmit pain: as previously described, some people are insensitive to pain stimuli. They do not notice that they have the symptoms of a disease and do not stop activities that seriously injure them. Usually the path that the pain stimuli must take is completely intact. It is therefore a reverse phantom pain effect. No pain is experienced while the pain receptors are intact.
3. The influence of psychological factors on the experience of pain: a number of psychological factors influence the pain experience.
   • The state of mind: anxiety and depression lower the pain threshold and cause someone to report pain more often. It also works the other way around: pain influences the state of mind.
   • Attention: when you give pain attention, the pain experience is increased. Someone who is injured during an important competition usually only feels the pain afterwards, when the adrenaline falls and there is attention again for things other than scoring points. Research into attention and pain with the so-called 'cold pressor test' in which participants have to put their hand in a bowl of ice water, showed that people who could focus on that lasted less than people who were distracted by a computer task.
   • Cognitions: when you think that the pain will get worse, that in itself is enough to actually experience the pain as increased.

Cognitive aspects that make a difference are:

• The cause to which you attribute the pain.
• Views on the possibility of ignoring pain.
• Views on the possibility of controlling pain.
• Expectations about when the pain will pass, the placebo effect.

People who think that their pain is due to psychological factors are more likely to do physical exercise than people who think their pain is physically determined. This last group of people is afraid that moving will make the pain worse. Certainly if there is a big difference between the expected pain and the actual pain, people will move less.

The extent to which someone can tolerate pain depends, among other things, on their previous experiences with pain, their previous behavior towards pain, the extent to which family members can tolerate pain, locus of control and expectations about their own pain tolerance.

Expectation of pain relief: the placebo response

One of the most fascinating phenomena associated with pain is the placebo response. There seems to be an advantage to simply receiving what appears to be a treatment, whether this is a tablet, an injection or other treatment. This is called the placebo effect. A placebo has no pharmacological effects. People with chronic pain who think that they will receive an anesthetic or a cure for their pain, but in reality receive a placebo, report a pain reduction of 50 percent on average in two thirds of the cases. This is apparent from research with people who suffer from chronic lower back pain. Two important mechanisms of the placebo effect are probably a classical conditioning reaction, and our expectations of pain or the reduction of pain. There are some guidelines for the use of a placebo:

• The intentions of the doctor must be good and respect the well-being of the patient.
• The placebo must be given for someone's suffering.
• The placebo should not be given if it is ineffective.
• The placebo cannot be given instead of another drug that the doctor expects to be more effective.
• The doctor should not hesitate to be honest about the nature and effects of the placebo treatment.
• If the patient is helped by the placebo, this should not be stopped in the absence of more effective treatment.

Social influence on pain

The experience of pain can be changed by the presence of others. Whether the reported experience of pain is different in the presence of others depends on the condition. Men report less pain when there is an attractive woman than when there is a man. It is not certain whether or not this reports the real experience of pain.

What is the psycho-biological theory of pain?

The 'Gate Control theory' of pain

So far we know that two processes are involved in pain experience, namely the sensory information of the pain site and the associated emotional and cognitive processes. The gate control theory of pain (GCT) takes both aspects into account and is recognized as a very good pain theory.

The essence of the model is that we experience pain as a result of two processes:

1. Pain receptors in the skin and other organs provide information about physical damage to a number of gate points in the spinal column. Within the gates, nerves make contact with other nerves that transmit the pain to the brain.
2. The moment the pain stimuli arrive in our brains, we also experience emotions and cognitions - fear, alarm. This information results in the activation of nerve fibres taking information from the brain down the spinal column to the gate at which the incoming pain signals enter the spinal column. 

The amount of pain that someone experiences depends on the activity of both systems. Activation of the sensory nerves opens the gates that activate the nerves to the pain centers, so that the pain is recognized as pain. However, the downward pathways activated by emotional and cognitive factors can also influence the position of the gate. Anxious thoughts can open the gate and increase our experience of pain.

There are different types of nerves that transmit information about pain at different speeds. For example, there are the A delta fibers that provide the experience of sharp pain. The A delta fibers respond to light touches, mechanical stimuli and temperature. The experience is short-lived.

The C polymodal fibers work slower and provide information about dull, throbbing pain. This pain is experienced for a longer period of time than the pain caused by the A delta fibers.

The A beta fibers provide tactile information, especially that of friendly touches. The information goes to the brain, so our first reaction is that we want to rub the painful area. The rubbing activates the A beta fibers and because that friendly touch information is processed first, it quickly has a slightly soothing effect.

The A and C fibers transmit pain to areas of the spinal cord called substantia gelatinosa. The nerve impulses cause the so-called substance P to be released. This substance in turn causes nerve fibers such as the T (from transmitter) fibers to be released that transmit the pain sensation to the brain.

Information from the A fibers goes to the thalamus so that someone can take action to get away from the source of pain. Information from the C fibers goes to the limbic system, the hypothalamus and the autonomic nervous system. The limbic system enables the emotional meaning and reaction and the hypothalamus regulates the activity of the autonomic nervous system so that someone can respond quickly to the pain.

The results of this are led down the spinal cord, which causes a number of chemicals to be released into the substantia gelatinosa. The most important and well-known substance is endorphin, which closes the door so that less pain is experienced. Activity in this system is influenced by a number of factors that all have an effect on the release of endorphins:

• Focusing on pain: worrying (catastrophizing) reduces the amount of endorphins released and opens the door.
• Emotional and cognitive factors: feeling optimistic and carefree about the meaning of the pain increases the release of endorphins and closes the door (anxiety, worry, anger or depression open the door).
• Physical factors: relaxation increases the release of endorphins and reduces the experience of pain.

What is meant by the neuromatrix?

Although the gate control theory offers a nice outcome as a theory of pain, it unfortunately cannot explain an important type of pain: phantom limb pain. Melzack has therefore made a more complex theory of pain mechanisms that attempt to explain this mysterious phenomenon. His model has three assumptions:

1. The same neural processes involved in pain perception in the intact body are involved in pain perception in the phantom limb.
2. All the qualities we normally feel of our body, including the pain, can be felt in the absence of the body's inputs.
3. The body is seen as a unity and is identified as the self, separated from other people and the world around it.

Melzich suggested that the anatomical substrate of the 'body-self' is a large network of neurons connected to the thalamus, the cortex and the limbic system in the brain. He called this system the neuromatrix. A neurosignature is a network of information about the origin and emotional responses of a pain stimulus. Neuro Signatures have two components:

1. The body-self matrix: integrates incoming sensory and emotional information;
2. The action neuromatrix: develops behavioral responses as a response to these networks.

How can people be helped to cope with pain?

The first-line treatment for acute pain is usually a pharmacological treatment ranging from aspirin to an opiate such as pethidine. Psychological interventions usually only appear later, when the pain is prolonged, when medication does not help or when anxiety is involved. This is often called the second line of intervention.

Measuring pain

The most used and fastest way to determine the severity of pain is to have people fill in a visual scale. For example, a scale from 0 to 100 where 0 stands for no pain and 100 for the worst pain that anyone can imagine. A disadvantage is that people often find it difficult to represent pain in numerical terms.

Another way is to let people choose from a number of words that describe pain, such as mild, disturbing, unbearable and so on. With this method it is often the case that people are very much in the middle of the scale and are insensitive to subtle differences in the descriptions.

A disadvantage of such measurements is that it merely measures the pain experience. The McGill pain questionnaire was developed with the intention of solving this problem. Measuring is more difficult because the method is complex. But it does provide a multidimensional description of the nature of the pain. The McGill questionnaire measures:

• The type of pain: all types of pain (stinging, throbbing, cramping, etc.) occur and it must be indicated on a scale with four points whether this is not the case at all or very bad or something in between.
• The emotional response to the pain: for example, whether you get tired of it, or scared, or whether it feels like punishment.
• The intensity of the pain: ranging from 'no pain' to 'worst possible pain ever'.
• The timing of the pain: whether the pain is short-lived, long-lasting, or whether it is a recurring and receding pain.

Although this questionnaire covers many aspects, it does not ask anything about a person's behavioral response to pain, and the relationship between pain and movements. Behavioral responses to pain can be verbal (sighing, supporting and complaining), motor behavior (leaving the face, being out of balance, becoming slow, not being able to sit, lying or standing and seeking help), treatment behavior (taking medication), and functional limitations such as resting and some activities cannot do.

Treating acute pain

There are a number of things that people can do to reduce acute pain. Most approaches focus on: increasing a person's sense of control over the pain and medical intervention. If someone thinks he has no control over the pain or what happens to him, it can increase the pain. When someone is in the hospital, he / she may be afraid that the hospital staff is so busy that they forget to give an anesthetic. Or they are afraid that their pain will be so bad that the anesthetic is not strong enough. One way to solve these problems is through patient-controlled anesthesia (PCA; patient-controlled anesthesia). This is a method whereby the patient can administer small amounts of an anesthetic to himself. Research shows that patients who can give themselves anesthesia are indeed less anxious and also experience less pain. The method also results in using smaller amounts of anesthesia than when a specialist determines the amount. This method can also be applied to children.

Learning coping skills such as distraction techniques and relaxation exercises is also a method that is used. The effect of distraction is that people do not fall into catastrophic thoughts and that they do not sit down until the pain comes. For example, by listening to music with a specific assignment, the concentration is shifted. When people try to focus their thoughts elsewhere, this actually makes the bad thoughts worse. It is best to perform a task that is not related to pain or emotion.

Relaxation means that people learn to relax the muscles in their body, especially those around the painful area. Firstly, this is effective because the relaxation of the muscles around the pain causes the pain to be experienced less intensely. Secondly, relaxation ensures that people can think of nicer things. So it also helps in the search for distractions. Relaxation has also been shown to stimulate endorphin release.

Hypnosis can also be used as a coping technique. Hypnosis is said to change patients' sensations, perceptions, thoughts, and behaviors. Most forms of hypnosis are aimed at relaxation, calmness and well-being. Or the patient is asked to think of pleasant things.

Treating chronic pain

Transcutaneous electrical nerve stimulation (TENS)

A popular way to manage pain is through electrical stimulation of A beta fibers. This method also stimulates C fibers to release endorphins. The method is known as transcutaneous electrical nerve stimulation (TENS) and uses a small electrical device that is placed on the painful area of ​​the skin. This allows a small electrical of low intensity to pass through the skin. The device is usually used several times a day and more than 15 minutes at a time. The studies investigating the effectiveness of TENS show varying results. Most studies indicate that TENS gives no better result than a placebo. However, the studies are small in size, not well controlled and with poor methodologies. More research is needed to confirm the results of TENS.

Relaxation and biofeedback

Relaxation can be used to relax the entire body or specific body parts. This way you can focus specifically on relaxing the forehead muscles, which can reduce headaches. To be able to relax certain parts, you also need to know which parts you are tightening. Relaxing specific muscle groups is often difficult but can be achieved with biofeedback techniques. These techniques use equipment that measures certain values ​​of, for example, tension in the body. For example, the heart rate or blood pressure can be measured. Because the patient always receives feedback from the body, the patient knows exactly what his condition is, and he knows immediately if the relaxation is successful. This prevents someone from always trying things that don't work. And the feedback works as a kind of reward system. For example, you hear a lower tone when you relax, this also ensures that the right techniques are conditioned.

An alternative way is to use an antidepressant in combination with the biofeedback method. The biofeedback method works with three methods:

• Electromyographic biofeedback (EMG): this measures the small amount of electrical current in the muscles. The voltage matches the muscle tension: higher voltage = higher tension.
• Galvanic skin response (GSR): measures general tension in the body by measuring subtle changes in sweat of the hand. More sweat relates to greater muscle tension, but this relationship is not one to one.
• Thermal biofeedback: based on a theory that warming the skin can reduce headache pain.

The effects of virtual reality feedback were also measured, in which children learned relaxation exercises while wearing a virtual reality system and were able to see positive, pain-free images of themselves. Biofeedback helps patients to make changes while being guided by feedback from physiological changes they produce. A specific problem where biofeedback is used successfully is with chronic headache. With other pains it is often no more effective than relaxation itself. Because relaxation is easier and cheaper, this is the preferred treatment. An alternative strategy is to combine relaxation with antidepressants. Indeed, antidepressants appear to reduce pain. It seems to work, like cognitive behavioral techniques, in reducing headache. A combination of antidepressants and cognitive behavioral techniques is the most effective treatment.

Behavioral interventions

Behavioral interventions for chronic pain mainly consist of operant conditioning. This principle is based on the assumption that we cannot understand the pain of another, but that we can only observe pain behavior. Fordyce therefore suggested that interventions should focus on seeing people's pain behavior. The pain behavior of people is partly caused by the reactions to pain that they see in others. Pain reactions can be very subtle, a slight change in facial expression or posture can betray someone in pain.

To prevent people from exhibiting pain behavior, you must ensure that this behavior is no longer rewarded and that other behavior is rewarded. For example, you can think of rewarding an appropriate amount of exercise, distracting someone from paying attention to rewards or previous reactions to pain and providing narcotic medication at regular intervals instead of when someone feels pain. In this way the new, effective behavior is encouraged. This method is particularly effective when the physical cause of the pain is low, or when there is nothing to do about it. It is more difficult to ignore pain or to approach it differently when a medical intervention would resolve everything.

Cognitive behavioral interventions

Cognitive behavioral interventions focus on changing behavior, but can also influence other parts of pain experience. Active participation in activities can distract a person's attention from negative cognitive and emotional responses. The resumption of activities that someone stopped earlier because the pain made this difficult increased one's self-confidence and optimism. Cognitive behavioral interventions address these effects even more directly. This method does not contradict the Gate Theory, but focuses on a number of factors that influence the gate.

The goals of cognitive behavioral therapy are:

• To help the patient realize that their pain can be regulated. Patients are helped to solve their own problems related to the pain so that they do not feel helpless and hopeless when it comes to dealing with the pain.
• Helping the patient to establish the relationship between thoughts, emotions and behavior. This allows them to see that doom-thinking has the effect that the pain is experienced as worse.
• The patient receives tips and learns strategies that help regulate pain, emotional stress and psychological problems. They teach effective ways of thinking, feeling and behaving.

The cognitive behavioral interventions can be offered both in groups and one to one, which benefits the price-quality ratio. The cognitive change must be learned through a number of phases, as has been discussed many times in previous paragraphs. Once people understand how their thoughts affect their experiences and behavior, they can learn more adaptive ways of thinking. These thoughts can be focused on the fact that the patient can cope with this pain earlier, or that it makes no sense to grind about it or get angry about it. Someone can also learn to think about relaxation as soon as the pain comes up.

A more complex way of cognitive behavioral intervention is trying to find out which thoughts cause emotional discomfort. These thoughts should then be seen as hypotheses instead of facts, so that the patient can look for indications that these hypotheses are incorrect. For example, as soon as you get a pain in your stomach you can immediately assume that this will take hours, but you can also take a deep breath and think that it will soon pass, just like it was last week. The exercises are usually built up gradually, so that people can get used to the new behavior and they can consciously learn about the effects of the new behavior.

Other ways of intervention that are also widely used are positive talk to yourself ("I can handle it, the pain is not forever"), taking a long, hot shower, imagining that you will get a narcotic and playing relaxation exercises or self-hypnosis instructions.

Many studies show time and (again) that cognitive behavioral interventions are very effective. It often appears to be more effective than pharmacological or educational therapy and other methods. However, cognitive behavioral therapy does not appear to be more effective than other therapies in reducing negative or catastrophic thoughts. The most important element is that people become more active than they were before, which improves their beliefs about their ability to move, exercise, pain control and the state of mind.

Temporomandibular disorder pain consists of conditions that cause pain in the temporomandibular joint.

There are clinics nowadays that specialize in pain relief. A range of specialists such as anaesthesiologists, physiotherapists, psychologists, doctors etc. are present in these clinics. Usually a personal program is drawn up that is aimed at pain relief and how to deal with pain.

Mindfulness-based interventions

Mindfulness interventions are becoming increasingly used in mental health settings. Meditating mindfulness daily is effective in reducing pain. Mindfulness works even better than CBT in reducing catastrophic beliefs about the nature and implications of pain and fatigue. CBT is therefore often combined with mindfulness.