Making Connections: Chronic Stress, Pain, & Addiction

Restless mind peace of mind sign with wetland background

“Stress” is such a seemingly small, simple word. People use it every day. “The morning commute is causing me stress.” “I’m so stressed out because I have a heavy patient load and not enough time in the day.” Both of these are valid, but the average person experiencing these types of stressors typically knows how to manage the weight of anxiety, knows how to self-soothe—by taking a walk, meditating, and/or practicing some simple self-care.

For the patient with addiction or persistent pain, however, stress may have become chronic, meaning the effect of a stressor on the body persists long after the initial insult has passed.1 Perhaps this individual’s self-soothing mechanisms were never developed in childhoodor they’ve been long abandoned. Whatever the reason, the fight or flight response simply will not turn off. Here, we are talking about persistent stress and traumatic stress—stress that is integrated into the bodily systems so seamlessly that one might not even realize it’s there. Yet studies have shown that the human experience of stress is mediated on multiple levels—genetic, biological, and cognitive.2

What is the role of stress in increasing the risk of chronic pain and maladaptive behaviors such as addiction? How can primary care clinicians help patients manage present-day anxiety and unravel the stressful patterns of childhood? Functional Medicine teaches clinicians how to help patients develop healthy coping mechanisms through lifestyle modifications like exercise, meditation, an anti-inflammatory diet, and more. Working together with patients, this therapeutic relationship has the power to change the trajectory of pain and addiction in a patient’s life.

In the following video, Henri Roca, MD, talks about the complexity of brain plasticity in patients struggling with stress, pain, and addiction, and describes how interventions can support healing.

Stress & Addiction

Stress is a key risk factor for addiction and also plays a role in its maintenance.1 Prefrontal circuits involved in adaptive learning and executive function play a critical role in both stress and addiction, in their ability to control distress as well as desires/impulses.3 Stress also has a cumulative effect in the body as it relates to addiction; the greater number of stressors an individual is exposed to throughout the course of their lives, the greater their chances of addiction.3

Studies show that the administration of abused drugs induces neurochemical changes in the brain that in turn alter the stress response and pain sensitivity.2 Both pain and addictive disorders are characterized by impaired hedonic capacity, compulsive drug seeking, and high stress.4 In drug addiction, these symptoms have been attributed to reward deficiency, impaired inhibitory control, incentive sensitization, aberrant learning, and anti-reward allostatic neuroadaptations.4

Co-occurring substance use and posttraumatic stress disorders (PTSD) are also prevalent in the patient population.5 These conditions can be challenging for clinicians because of their complexity and ties to early childhood trauma resulting in PTSD. Exposure to trauma, neglect, or abuse—especially early in life—is an important determinant of health status, particularly as it relates to stress and addiction.6 Major stressors experienced before the brain is fully developed can increase the odds of developing a substance use disorder (SUD) later in life, as it may actually damage regions of the brain used for controlling impulses and making good decisions.7

Studies have shown that there is high comorbidity between PTSD and substance use disorder; people who suffer from PTSD are between two and four times more likely to also battle addiction.5 In a study of adolescents who were being treated for issues surrounding substance abuse, almost three-fourths reported a childhood trauma.8

The association between adverse childhood experiences and unhealthy adult lifestyles has been well documented. Groundbreaking research in 1998 looked at how 10 types of childhood trauma affect long-term health. The Kaiser Adverse Childhood Experiences (ACE) study shows that child abuse and neglect are the single most common cause of drug and alcohol abuse. For every additional ACE score, the rate of number of prescription drugs used among adolescents increased by 62%.9 Similarly, the prevalence of risk of alcoholism, use of illicit drugs, injection of illicit drugs, number of intercourse partners, and history of a sexually transmitted disease also increased as the number of childhood exposures to trauma increased.6

Risk factors examined in the ACE study include examples of multiple stressors (child abuse or neglect, parental substance abuse, and maternal depression) that are capable of inducing a toxic stress response.6 Research by the Centers for Disease Control and Prevention has shown that one in five Americans was sexually molested as a child; one in four was beaten by a parent to the point of a mark being left on their body; and one in three couples engages in physical violence. A quarter of US adults grew up with alcoholic relatives, and one out of eight witnessed their mother being beaten or hit.10

“It takes tremendous energy to keep functioning while carrying the memory of terror, and the shame of utter weakness and vulnerability,” writes trauma and addiction expert Bessel van der Kolk, MD, in his book, The Body Keeps the Score.

“As long as you keep secrets and suppress information, you are fundamentally at war with yourself … The critical issue is allowing yourself to know what you know. That takes an enormous amount of courage.”10

Stress & Chronic Pain

Pain patients have been found to exhibit heightened levels of stress and arousal, and stress for these patients may also exacerbate pain symptomology, including sympathetically maintained pain and nocebo effect.11 The last several decades have seen an increase in the treatment of chronic pain, predominantly by primary care physicians.12

Research suggests that stress is implicated across the entire spectrum of painful phenomena, and that chronic pain—in and of itself—may be viewed as a self-amplifying stressor that contributes to the allostatic load by impairing sleep and autonomic function, as well as by promoting systemic inflammation.4 Clinically, pain patients exhibit heightened levels of stress and arousal.12

Similar to addiction, evidence supports high rates of co-occurrence of PTSD and chronic pain disorders involving central sensitization.13 In a 2019 study of 202 adult patients with chronic pain, both trauma exposure and PTSD symptoms were significantly associated with all three clinical indicators of central sensitization. PTSD symptoms partially explained the relationship between trauma exposure and widespread pain, pain intensity, and polysomatic symptoms.13

Pain has both somatosensory (physical) and somatoaffective (emotional) components, and is processed and interpreted in the context of higher-order cognitive processes; therefore, studies suggest that pain assessment should include both a physical and a psychosocial component.12 The biopsychosocial model of pain unifies physical and psychosocial aspects of pain.12 Some empirical studies suggest that the way patients regulate their emotions may be relevant to chronic pain and PTSD.14 Experiential avoidance (attempts to avoid thoughts, feelings, memories, physical sensations, and other internal experiences—even when doing so creates harm in the long-run) is also common among chronic pain patients.15 Some studies suggest that while experiential avoidance may amplify the impact of stress and pain, mindfulness and acceptance may reduce this effect.16,17


Stress, pain, and maladaptive behaviors are all part of the human experience. Primary care physicians, who are often at the forefront of a patient’s healthcare journey, play a critically important role in assessing for these disorders. Identifying the origins of adult disease and addressing them through tools like the IFM Timeline are critical steps toward changing patient outcomes.

Functional Medicine clinicians seek to identify the underlying causes of complex diseases like pain and addiction—to examine antecedents, triggers, and mediators—and help patients take active ownership of their health. By forming a therapeutic relationship, Functional Medicine clinicians can begin to see the whole person, and never the symptom alone. As Bessel van der Kolk says so eloquently:

“I can’t begin to imagine how I would have coped with what many of my patients have endured, and I see their symptoms as part of their strength—the ways they learned to survive. And despite all their suffering many have gone on to become loving partners and parents, exemplary teachers, nurses, scientists, and artists.”10

Learn more about stress, pain, and addiction with the 2019 annual conference proceedings


  1. Sinha R, Jastreboff AM. Stress as a common risk factor for obesity and addiction. Biol Psychiatry. 2013;73(9):827-835. doi:10.1016/j.biopsych.2013.01.032
  2. Nakajima M, al’Absi M. Addiction, pain, and stress response. In: al’Absi M, Flaten MA, eds. Neuroscience of Pain, Stress, and Emotion: Psychological and Clinical Implications. Elsevier; 2016:203-229. doi:10.1016/B978-0-12-800538-5.00010-8
  3. Sinha R. Chronic stress, drug use, and vulnerability to addiction. Ann N Y Acad Sci. 2008;1141:105-130. doi:10.1196/annals.1441.030
  4. Elman I, Borsook D. Common brain mechanisms of chronic pain and addiction. Neuron. 2016;(89)1:11-36. doi:10.1016/j.neuron.2015.11.027
  5. McCauley JL, Killeen T, Gros DF, Brady KT, Back SE. Posttraumatic stress disorder and co-occurring substance use disorders: advances in assessment and treatment. Clin Psychol. 2012;19(3). doi:10.1111/cpsp.12006
  6. Felitti VJ, Anda RF, Nordenberg D, et al. Relationship of childhood abuse and household dysfunction to many of the leading causes of death in adults. The Adverse Childhood Experiences (ACE) study. Am J Prev Med. 1998;14(4):245-258. doi:10.1016/S0749-3797(98)00017-8
  7. Arain M, Haque M, Johal L, et al. Maturation of the adolescent brain. Neuropsychiatr Dis Treat. 2013;9:449-461. doi:10.2147/NDT.S39776
  8. National Child Traumatic Stress Network. Making the connection: trauma and substance abuse. Published June 2008. Accessed April 11, 2019.
  9. Forster M, Gower AL, Borowsky IW, McMorris BJ. Associations between adverse childhood experiences, student-teacher relationships, and non-medical use of prescription medications among adolescents. Addict Behav. 2017;68:30-34. doi:10.1016/j.addbeh.2017.01.004
  10. van der Kolk B. The Body Keeps the Score: Brain, Mind, and Body in the Healing of Trauma. Viking; 2014.
  11. Roderigo T, Benson S, Schöls M, et al. Effects of acute psychological stress on placebo and nocebo responses in a clinically relevant model of visceroception. Pain. 2017;158(8):1489-1498. doi:10.1097/j.pain.0000000000000940
  12. Owen GT, Bruel BM, Schade CM, Eckmann MS, Hustak EC, Engle MP. Evidence-based pain medicine for primary care physicians. Proc (Bayl Univ Med Cent). 2018;31(1):37-47. doi:10.1080/08998280.2017.1400290
  13. McKernan LC, Johnson BN, Crofford LJ, Lumley MA, Bruehl S, Cheavens JS. Posttraumatic stress symptoms mediate the effects of trauma exposure on clinical indicators of central sensitization in patients with chronic pain. Clin J Pain. 2019;35(5):385-393. doi:10.1097/AJP.0000000000000689
  14. Serrano-Ibáñez ER, Ramírez-Maestre C, Esteve R, López-Martínez AE. The behavioral inhibition system, behavioral activation system and experiential avoidance as explanatory variables of comorbid chronic pain and posttraumatic stress symptoms. Eur J Psychotraumatol. 2019;10(1):1581013. doi:10.1080/20008198.2019.1581013
  15. Costa J, Pinto-Gouveia J. The mediation effect of experiential avoidance between coping and psychopathology in chronic pain. Clin Psychol Psychother. 2011;18(1):34-47. doi:10.1002/cpp.699
  16. McCracken LM, Keogh E. Acceptance, mindfulness, and values-based action may counteract fear and avoidance of emotions in chronic pain: an analysis of anxiety sensitivity. J Pain. 2009;10(4):408-415. doi:10.1016/j.jpain.2008.09.015
  17. Thompson RW, Arnkoff DB, Glass CR. Conceptualizing mindfulness and acceptance as components of psychological resilience to trauma. Trauma Violence Abuse. 2011;12(4):220-235. doi:10.1177/1524838011416375

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