The Interaction Between Psychological Factors And Physical Pain Symptoms
Chronic pain is a debilitating condition that affects millions of people each year across the world. Historically, pain has always been viewed as a purely biological process and psychological and social factors were considered irrelevant. If no obvious organic cause could be found, patients were often referred to a psychiatrist for treatment for their condition, which was deemed ‘psychogenic’ in nature. More recently, it has been recognised that each person experiences pain in a different and often subjective way, and the rise of psychosomatic medicine has revealed the important connection between biological and psychosocial factors which underlies this. The biopsychosocial model of pain evaluates the ‘whole person’ and views the mind and body as interconnected entities, recognising that there are biological, psychological and social aspects to pain and illness. Every individual possesses a unique combination of these factors, and the interactions between them will shape the way in which pain is felt and also explain the unique symptom patterns displayed by patients.
The interaction between pain and psychosocial factors appears to be a two-way process. It is clear that chronic pain produces stress in the patient, but this stress can also make the pain worse, exacerbating the patient’s condition and making it harder to manage. Stress leads to the release of cortisol, which is detrimental if it occurs over an extended period of time. Continuous increased activation of the hypothalamic-pituitary-adrenal axis can lead to damage to the muscles, bones and tissues, resulting in more pain. Therefore, a vicious cycle of pain and stress is likely. Furthermore, serotonin and norepinephrine are involved in the pain pathway, but are also implicated in the development of mood disorders. If the nervous system is consistently in a highly reactive state, central sensitisation occurs. This phenomenon has been linked with the development and maintenance of chronic pain states. As a result of central sensitisation, pain sensations become distorted and pain receptor thresholds are lowered, and these factors will affect the individual pain experience.
If a chronic pain condition is associated with the onset of psychological issues, or the exacerbation of existing ones, the mental deconditioning that results can lead to the development of learned helplessness, anxiety disorders, substance abuse and depression, all of which are common among patients with chronic pain. Other emotional effects include catastrophising, fear-avoidance strategies and issues of efficacy, control, vulnerability and resilience. Catastrophising, which can be defined as the tendency to dwell on the worst possible outcome of any situation and overestimation of the chances of it occurring, appears to be particularly important in the moderation of pain. It has been consistently linked with increased self-reported levels of pain and anxiety. However, it is important to remember that none of these factors directly causes pain, although they can contribute to a person’s perception of it, and their response to both pain and treatment.
The differences in patient experience highlighted by the biopsychosocial model reveal the need to tailor pain management programs to the individual patient. Therefore, the initial assessment to determine which patients might benefit from an interdisciplinary, as opposed to a multidisciplinary, approach can have a profound effect on treatment outcome. While both approaches utilise the skills of several different practitioners, interdisciplinary treatment incorporates these into a cohesive team that is responsible for all aspects of patient care, as opposed to the multidisciplinary approach, where each discipline treats the patient separately from their own perspective. There is now evidence that cognitive behavioural approaches can be particularly effective, as this method helps to identify, evaluate and change negative beliefs surrounding pain and behavioural responses to it. Often, pain relief is not a primary goal of this type of treatment, which instead works towards achieving optimal functioning and self-reliance to assist in managing persistent pain. However, coping strategies that help a patient to come to terms with their condition can also help to reduce psychological distress, which may in turn reduce a patient’s perception of pain.
Given the two-way relationship between pain and psychological issues, a major barrier to the success of any pain treatment program is the existence of pre-existing psychiatric conditions. These include depression, anxiety and other indices of emotional distress, along with previous trauma and post-traumatic stress disorder (PTSD). There is overwhelming evidence that all of these factors contribute significantly to long-term outcomes of persistent pain, such as physical disability, healthcare costs and mortality. Of all these factors, PTSD arguably shows the strongest association with chronic pain, and it also plays a role in the transition from acute to chronic pain. However, it is not clear whether the association between trauma and chronic pain is direct or is driven by emotional, cognitive and behavioural responses to the traumatic event.
Pain is a complex condition and each patient will experience it differently. Effective management requires an understanding that multiple factors, both physical and psychological, may be responsible for the initiation and maintenance of chronic pain, and the influence of these may alter over time. The biopsychosocial model acknowledges that as well as physiology, predisposition to illness or injury, psychological and social factors are all important in the development and treatment of chronic pain.
Bevers K, Watts L, Kishino ND, Gatchel RJ. The biopsychosocial model of the assessment, prevention, and treatment of chronic pain. US Neurol. 2016;12(2):98–104.
Innes S. I. (2005). Psychosocial factors and their role in chronic pain: A brief review of development and current status. Chiropractic & Osteopathy, 13(1), 6. https://doi.org/10.1186/1746-1340-13-6