This review provides an overview of learning mechanisms and memory aspects for the development of chronic pain.
Pain can be influenced in important ways by an individual’s personality, by family, and by the sociocultural environment in which they live. Therefore, learning mechanisms can explain why pain experience and pain behavior can increase or decrease.
Linking pain with positive consequences or removing negative consequences can contribute significantly to the chronification of pain.
If pain were linked with positive consequences, we wouldn’t mind having it, but I find it impossible to imagine how to link even moderate pain with anything positive.
In this case, I think they are confusing “pain behaviors”, with pain itself.
We will provide an overview of treatment options that use the characteristics of extinction.
Operant extinction training and cognitive behavioral approaches show promising results for the treatment of chronic pain.
Learning mechanisms are a basic concept in behavioral medicine. There are different mechanisms involved in learning, such as classical and operant conditioning, extinction, habituation, and sensitization.
Classical conditioning is a learning procedure in which a biological potent stimulus is paired with a former neutral stimulus.
Whenever he fed his dog, he rang a bell and gave him food. After some time, the dogs salivation was present just by ringing the bell without presenting the food.
Another learning procedure is operant conditioning. This procedure is characterized by the fact that the behavior is modified by reinforcement or punishment. During this learning process, an association is made between a behavior and a consequence for that behavior
The question arises as to whether it is possible to reverse the learning process and unlearn a behavior. This process is called extinction and it can be used to unlearn classical or operant conditioned behavior.
these learning mechanisms rely on two processes:
- habituation and
Habituation occurs if someone no longer notices a stimulus that is repeatedly presented without a reward, punishment, or change in intensity
Sensitization refers to the increase in the strength of a reaction with repeated presentation of the same stimulus.
Repeated pain definitely sensitizes both the body and the mind.
However, it has to be noted that all learning mechanisms and behaviors described above can be influenced in important ways by an individual’s
- family, and the
- sociocultural environment.
Pain is an important evolutionary response signaling danger to the body and triggering protective responses. There is a distinction between acute and chronic pain:
- Acute pain is usually the reaction to stimulation, has a direct cause, and fulfills an adaptive signal function, whereas
- chronic pain (duration of at least 3–6 months and/or exceeding the usual healing time for acute injuries) conditions often have no direct cause of pain.
After chronification, the pain has lost its basic positive function and becomes an independent disease, which is associated with significant limitations and requires special treatment.
If someone suffers from a chronic disease, such as chronic pain, this chronic disease is often associated with a great burden. This burden can result from the disease itself, but also from the associated diagnostic and medical therapeutic measures.
The uncertainty about the future of living with this chronic disease can be a particularly strong stressor.
This uncertainty arises every day: we have no idea how our pain levels will fluctuate during the day and even less certainty about what our pain level will be the next day or any day in the future. This makes planning difficult, if not impossible.
2.1. Operant Learning
Chronic pain can get worse by pain behavior.
Fordyce postulated that acute pain behavior, such as moaning or hobbling, under the control of an external amplifier could strengthen the pain and contribute to its chronification.
The learning mechanisms behind this process are
- positive reinforcement (e.g., attention or the expression of pity),
- negative reinforcement of pain behavior (e.g., adopting a pain relieving posture), and
- alack of reinforcement of healthy behavior (e.g., physical activity).
These learning processes can maintain chronic pain, even in the absence of a nociceptive influx.
This is not true for every pain patient with any diagnosis in every situation. I believe this is a sweeping generalization that does not belong in a scientific article.
Linking pain with positive consequences or removing negative consequences leads to increased pain behavior at all levels (e.g., work, leisure, and family) and can contribute significantly to the chronification of pain
These researchers don’t seem to notice there’s a difference between pain and pain behavior.
Pain behavior, originally induced by nociceptive processes, can occur because of learned environmental contingencies.
research was also able to prove that pain sensation and physiological processes of pain processing are operant conditioned.
The reaction towards people who suffer from pain can be divided into three different types:
- those who reinforce the pain (e.g., expression of compassion, solicitous responses, attention),
- those who try to distract them from pain (e.g., taking a walk), and
- those who ignore them (e.g., go out of the room)
In a test situation, the pain behavior of chronic pain patients depended on the presence or absence and the reinforcement pattern of their significant other.
When the significant other showed comforting and caring behavior towards the chronic pain patient, the pain increased in contrast to a situation without the significant other
During the process of dealing with pain, the interaction between the significant other and the pain patient is an important underlying factor.
Equally important are conditioning processes of taking pain medication.
Patients often hear from their doctors or well-meaning family members that they should take painkillers if the pain is really strong and they ‘need’ the medication.
Patients learn to associate high perceived pain with medication intake.
Well, duh! We also associate high hunger with food intake and high thirst with liquid intake. This is how we’re supposed to function – it’s not an aberration.
The pain might be reduced in the beginning, but along the way the amount of medication and the frequency of medication intake will increase, leading to medication abuse or dependency.
Again a sweeping assumption, repudiated by many pain patient reports of staying on stable doses for many years and even decades.
It’s the euphoria experienced by misusing opioids that so quickly requires escalation, not the pain relieving properties.
For the effectiveness of a certain pain medication, however, a constant plasma level might be needed. Thus, both behavioral therapists and physicians/pharmacologists recommend a time-contingent medication intake, instead of a pain-contingent medication intake. This means the medication should be taken at fixed times of the day, independent from the pain intensity.
This is the typical nonsense promoted by those who don’t understand how much our pain may vary.
These generalizations come about because of the assumption that all pain is basically the same.
I know some chronic pain situations are like this, but many others are not, like EDS or even fibromyalgia.
If we’re forced to take pain medication when our pain isn’t severe, it leads to more rapid tolerance and potential euphoria because the amount of opioid is more than is being consumed to combat pain.
The negative reinforcement of the activity level is also an important process in the development of disability. If a specific physical activity—for example, walking—is performed until the occurrence of pain, the patient has to interrupt the activity and rest until the pain decreases.
As a result, the patient learns that a reduction of activity reduces pain, leading to lower activity levels and, consequently, muscle atrophy.
Another sweeping and insulting generalization: of course we learn that a reduction in activity results in less pain. Indeed a complete and permanent absence of pain can only be found in death.
Because most of us take only enough opioids to lessen our pain, not eliminate it, if we just stopped doing everything that caused us pain we’d be prisoners of our beds.
Most patients want to retain as much of their functionality as they can, and we know that involves experiencing pain.
It never occurs to researchers that we are more complicated than animals and might have other motivations to be active that override the increasing pain.
2.2. Respondent Learning and Sensitization
The model of respondent (or classical) conditioning postulates that many previously neutral stimuli are connected to the pain experience from a previous injury.
Thus, without the need for a nociceptive input, this association can be coupled with physical reactions and finally trigger pain.
From the respondent perspective, muscle tensions formerly elicited from pain are associated with another arbitrarily stimuli. Sitting, standing, bending over, or walking—or even just thinking about these activities—might trigger anxiety and increase muscle tension.
This fear of movement, or “kinesiophobia”, as well as the associated fear of pain, are important factors in the development, maintenance, and chronification of pain.
The repeated presentation of painful stimuli usually leads to habituation, which means a decrease in the reaction to the stimulus.
On the contrary, in sensitization, the repeated stimulation leads to an increase in reaction to the stimulus.
However, in many chronic pain conditions, sensitization occurs rather than habituation.
I’ve often wondered why pain is a sensation we don’t become habituated to since we so readily adapt to touch, like not noticing the watch we’re wearing on our wrist.
Being hypersensitive to pain has been referred to as central sensitization.
There are two main characteristics for central sensitization, which involve
- heightened sensitivity to a painful stimulus (hyperalgesia) and
- the sensation of pain from stimuli (temperature, touch) that do not normally provoke pain (allodynia).
3.1. Characteristics of Extinction
Generalization processes happen easily during learning of pain-related behaviors. In contrast, however, the extinction or unlearning of pain is specific to the stimulus and the response, as well as the context during the extinction process
Therefore, it is more difficult for therapists to train a patient to unlearn pain-related behaviors compared with training them to learn these behaviors.
This is the corollary of “It takes 100 repetitions to develop a good habit, but only 3 to break it.”
During this process, it is not only the erasure of an old memory trace that occurs, but also the learning of a new suppressive process.
It’s always easier to learn something new than to forget the old, so it’s best to create many positive experiences that contradict negative behaviors learned.
Operant extinction training and cognitive behavioral approaches, which are specifically suited to influence learning and memory processes by modulating alterations in brain function or chemistry, were reported to be successful for the treatment of chronic pain.
Ignoring pain doesn’t make it go away, so with pain, extinction is impossible for anyone who has intermittent severe pains.
3.2. Operant Extinction Training
It is assumed that patients with high levels of pain behaviors and high interference from pain will benefit from operant extinction training
The goals of this training are as follows:
- to decrease pain behaviors in an effort to extinguish pain;
- to increase activity levels and healthy behaviors related to work, leisure time, and family;
- medication reduction and management; and
These seem to make many assumptions about chronic pain patients because it treats them as a population, not individuals.
While this might work for people with low-level consistent pain, some of us experience increasing pain the longer we don’t “do something about it”, like take an opioid so we can get on with our daily lives.
3.3. Cognitive Behavioral Training
The cognitive-behavioral model of chronic pain emphasizes the role of cognitive, affective, and behavioral factors in the development and maintenance of chronic pain.
The cognitive-behavioral training modifies pain-eliciting and maintaining behaviors, cognitions, and emotions to reduce feelings of helplessness and lack of control with the aim of establishing a sense of control over pain.
These behaviors do not “elicit and maintain” our own pain, it just makes our pain obvious to bystanders which makes THEM feel pain.
Therefore, a modification of pain triggering and pain maintaining behavior, as well as the involved cognitions and emotions, will be used.
Whereas operant treatment especially reduces pain behaviors and pain intensity, cognitive-behavioral therapy has a special effect on the affective and cognitive aspects of pain
cognitive-behavioral treatment changes the brain’s processing of pain through an altered cerebral loop between pain signals, emotions, and cognitions, which leads to increased access to executive regions for reappraisal of pain
Because extinction is more difficult than acquisition, principles of extinction training as described above need to be considered
Conclusions and Outlook
The goal of this review was to provide an overview of learning and memory aspects for the development of chronic pain.
We provided an overview of some treatment options that use the characteristics of extinction.
Operant extinction training and cognitive-behavioral approaches show promising results for the treatment of chronic pain.
I have to wonder which kind of pain they’re talking about becuase pain has so many different varieties and causes.
Just because they don’t know what’s causing our pain it doesn’t mean there isn’t a cause. It could be (and I think often is) a physical process that hasn’t been discovered yet.
Look how long fibromyalgia was considered “not real” before they found specific biochemical markers. They still don’t know what causes the body systems to go awry, but now they can detect it in blood or brain scans.