This article is part of the Expert Guide “Understanding Pain”.

When Physical Pain and Psychological Suffering Sustain Each Other: Adaptive Pain Loops

Why does this article matter?

The previous articles presented several levels of pain separately: nociceptive painNociceptive painNociceptive pain is pain related to actual or threatened damage to non-neural tissue, resulting from the activation of nociceptors. The somatosensory nervous system is functioning normally.Read the full entry : Nociceptive pain, mechanical involvement of a nerve, neuropathic painNeuropathic painNeuropathic pain is pain caused by a lesion or disease of the somatosensory nervous system.Read the full entry : Neuropathic pain, nociplastic painNociplastic painNociplastic pain is pain arising from altered nociception, without clear evidence of tissue damage activating nociceptors, or of a lesion or disease of the somatosensory system sufficient to explain the pain.Read the full entry : Nociplastic pain, nervous system hypersensitization, neurosensory learning, and psychological suffering. This separation was indeed necessary in order to understand each mechanism precisely.

In real life, however, these mechanisms rarely remain isolated. Pain can alter sleep, movement, attention, mood, social relationships, and protective strategies. These changes can then act back on the pain. This synthesis article therefore shifts to a different level of explanation: it no longer describes an additional mechanism, but how the mechanisms are organized in relation to one another.

Chronic painChronic painPain is called chronic when it persists or recurs for more than three months. It may accompany an identified disease or be a condition in its own right.Read the full entry : Chronic pain is not always sustained by a single cause. It can persist because several responses of the living organism, having become interdependent, reinforce one another.

1. How can physical pain become all-encompassing suffering?

In fact, prolonged physical pain does not necessarily remain confined to the area that hurts. When it recurs or persists, it can disrupt sleep, reduce endurance, limit getting around, make certain positions dreaded, and curtail activities that were previously routine.

In particular, lack of sleep increases fatigue and reduces adaptive capacity. Reduced activity can lead to deconditioning, a loss of confidence, and fewer reassuring bodily experiences. Diagnostic uncertainty or repeated treatment failures can foster worry. When social relationships, work life, or intimacy are affected, physical pain also becomes biographical and psychological suffering.

The literature on the comorbidity of pain and depression shows that these two dimensions are frequently associated and that their coexistence tends to increase functional impact (Bair et al., 2003). This association does not establish a single causal direction: pain can promote psychological suffering, psychological suffering can precede pain, and the two can share certain vulnerability factors.

2. How can psychological suffering amplify pain?

In fact, the nervous system never processes pain-related information independently of context. Attention, expectations, fear, emotional state, and threat appraisal influence the way signals are filtered, amplified, or inhibited. Descending pathways originating in the brain can exert inhibitory or facilitatory effects on nociceptive transmission (Ossipov et al., 2010).

Conditioned pain modulation shows that the nervous system’s ability to dampen a pain signal varies from one person to another and can be impaired in some chronic pain conditions (Yarnitsky, 2010). This does not mean that psychological suffering necessarily “creates” physical pain, but that it can alter the systems that appraise and regulate that pain.

Chronic stress, moreover, represents another level of interaction. Stress responses are normally adaptive: they mobilize the body in the face of a threat. When they are prolonged, however, they can alter sleep, attention, memory, emotional regulation, and several neurobiological systems involved in adaptation (McEwen, 2007).

The fear-avoidance modelFear-avoidance modelThe fear-avoidance model describes the possible relationships between how a person interprets pain, fear, avoidance and activity restriction. It is an explanatory model, not a diagnosis.Read the full entry : Fear-avoidance model describes how a sensation interpreted as dangerous can trigger fear, vigilance, avoidance, and reduced activity. These responses are understandable and often protective in the short term. When they become generalized, however, they can contribute to deconditioning, to the loss of corrective experiences, and to the persistence of pain (Crombez et al., 2012).

3. Why speak of a loop rather than a chain?

A chain implies a simple sequence: a cause produces an effect, and then the process stops. A loop, by contrast, describes a different kind of organization: the effect produced in turn becomes a new condition capable of reinforcing the initial process.

For example, pain disrupts sleep. Lack of sleep thus increases fatigue and lowers load tolerance. Fatigue reduces activity and increases the perceived cost of movement. Reduced activity limits reassuring experiences and can heighten attention to the body. Likewise, hypervigilance increases the detection of sensations. Those sensations then seem more threatening and can intensify the pain, which disrupts sleep even further.

In another case, for example, pain while sitting leads to protective strategies. The person freezes, avoids certain weight-bearing positions, or holds a posture assumed to be less painful for long periods. These adaptations can temporarily reduce discomfort, but they can also decrease mechanical variability, concentrate stress on other areas, and reinforce the fear of moving. The protective response then becomes one of the conditions sustaining the very problem it was trying to avoid.

4. Not all adaptations are pathological

In fact, the term “adaptive” does not mean that every adaptation is beneficial in the long term. It first describes a response of the living organism to a stress. Temporarily taking weight off a painful area, slowing down movement after an injury, or increasing vigilance in the face of a threat are coherent responses. In this sense, they protect the system during a phase when its capacities are reduced.

The difficulty arises when the stress changes but the adaptation persists, becomes generalized, or combines with other responses. A strategy that is useful for a few days can become costly when it shapes movement, attention, or behavior over the long term. The protection is not “wrong” in that case; it has become ill-suited to the new state of the system.

This distinction avoids two symmetrical errors: regarding every adaptation as pathological, or assuming that a biological response is necessarily favorable because it is natural. In other words, an adaptation can be immediately protective while becoming, over time, a sustaining factor.

5. How do the previous articles fit into this model?

The notion of adaptive loops offers a way to revisit the previous articles without conflating them:

• Article 3 — Nociceptive pain: a stress exceeds a tissue’s adaptive capacity and produces nociceptive activity.
• Article 4 — Compressed nerve or nerve under tension: mechanics, microcirculation, and nerve glidingNerve glidingNerve gliding refers to the movement of a nerve relative to the surrounding tissues during movements of the limbs, the spine or the pelvis.Read the full entry : Nerve gliding can interact over time.
• Article 5 — Neuropathic pain: a lesion or disease of the somatosensory system can persist after the initial stress has disappeared and lead to new adaptations.
• Article 6 — Nociplastic pain: the processing of pain-related information can be lastingly altered without tissue or nerve damage sufficient to explain the intensity of the clinical picture.
• Article 7 — Nervous system hypersensitization: increased sensitivity, hypervigilance, and avoidance behaviors can reinforce one another.
• Article 8 — Neurosensory deprogrammingNeurosensory deprogrammingNeurosensory deprogramming refers, in the functional model developed by Blue Portance from the work of Pierre Ivaldi, to the progressive loss of the nervous system’s ability to calibrate its response correctly based on the sensory information it actually receives.Read the full entry : Neurosensory deprogramming: certain learned responses can be gradually modified through new sensory and motor experiences.
• Article 9 — Psychological pain: psychological suffering is a biological and subjective reality that can interact with physical pain.

Article 10 therefore does not replace any of the preceding mechanisms. It shows why chronic pain can become difficult to understand when several levels — tissue, nerve, central, behavioral, emotional, and social — change at the same time.

6. What the biopsychosocial model contributes — and what it does not say

The biopsychosocial model was proposed to move beyond a strictly biomedical conception in which every disease should be explained by an isolated lesion (Engel, 1977). Applied to chronic pain, it calls for biological, psychological, and social factors to be analyzed together rather than set against one another (Gatchel et al., 2007).

This approach does not mean that all pain is psychological, nor that all factors carry the same weight in every person. An active mechanical stress may remain dominant; a nerve lesion may explain an essential part of the clinical picture; hypersensitization may become predominant; major stress or a social rupture may profoundly alter the trajectory.

7. The interpretation proposed by Blue Portance: from the adaptive system to pain loops

8. Is it possible to get out of an adaptive loop?

A loop is not, however, necessarily irreversible. Because it depends on relationships between several elements, it can change when one of those elements changes in a lasting way. Restoring sleep can improve emotional regulation and load tolerance. Gradually reintroducing movement can provide new safety information. Reducing a dominant mechanical stress can decrease the nociceptive activity that feeds the system as a whole.

The point is not to draw up a universal list of interventions, but to understand a logic: when pain is sustained by several loops, an isolated action may be insufficient, whereas a coordinated strategy may produce effects beyond the lever directly targeted.

This approach also helps avoid an interpretation that assigns blame. Indeed, a person does not “choose” their adaptive loops. They develop out of biological responses, experiences, stresses, and contexts that are often imposed. Understanding how they are organized is thus intended to restore possibilities for action, not to place responsibility for the pain on the person experiencing it.

9. Why does some pain become so difficult to treat?

What makes chronic pain particularly difficult to treat is not always the persistence of an isolated mechanism. In reality, it is sometimes the gradual formation of several loops that sustain one another. Each becomes both a consequence of the others and a factor sustaining them.

Understanding these interactions certainly does not mean that they are all present in every person. It can, however, help identify, for a given situation, which loops have become dominant, which remain secondary, and which relationships can be acted on.

For a long time, the question was whether pain was physical or psychological. Current knowledge instead invites us to understand how physical, nervous, emotional, behavioral, and social dimensions can interact. Recognizing these interactions does not amount to psychologizing pain. It means recognizing the complex organization of living systems.

This article is educational in purpose. It therefore cannot establish the dominant mechanism of an individual person’s pain, and it does not replace a medical diagnosis or personalized care.

© Gil Ayache. The concepts, diagrams, terminology, and principles presented on this page constitute a work protected by copyright. They are made available to Blue Portance under an intellectual property license agreement, without transfer of economic rights or of authorship.