Abdominal pain is a complex phenomenon that involves unpleasant sensory and emotional experiences caused by actual or potential visceral tissue damage. As pain becomes chronic, there is a functional reorganization of the brain involved in emotional and cognitive processing leading to amplification of pain perception and associated pain suffering.1,2 With the rising recognition of the complexity of pain management in the 1960s, the treatment of pain became a recognized field of study, leading to the formation of interdisciplinary teams to treat pain. However, although efficacious, this model lacked adequate reimbursement structures and eventually subsided as opioids (which at the time were widely believed to be nonaddictive) become more prevalent.3 Not only is there a lack of empirical evidence for opioids in the management of chronic abdominal pain, there is a growing list of adverse consequences of prolonged opioid use for both the brain and gastrointestinal tract.4
Recently, there has been more clinical focus on behavioral interventions that can modulate gut pain signals and associated behaviors by reversing maladaptive emotional and cognitive brain processes.5 One such psychological process that has received little attention is the traumatizing nature of chronic abdominal pain. Chronic pain, particularly when it feels uncontrollable to patients, activates the brain’s fear circuitry and drives hyperarousal, emotional numbing, and consolidation of painful somatic memories, which become habitual and further amplify negative visceral signals.6,7 These processes are identical to the symptom manifestations of posttraumatic stress disorder (PTSD) such as intrusiveness, avoidance, negative mood and cognitions, and hyperarousal from life events. In fact, individuals with a history of other traumatizing exposures have an even higher risk of developing chronic pain disorders.8 This review has two objectives: to provide a theoretical framework for understanding chronic pain as a traumatizing experience with posttraumatic manifestations and to discuss behavioral interventions and adjunctive nonopioid pharmacotherapy embedded in multidisciplinary care models essential to reversing this negative brain-gut cycle and reducing pain-related suffering.
Trauma and chronic abdominal pain
Trauma is defined as an individual’s response to a threat to safety. Traumatized patients or those with PTSD are at higher risk for chronic abdominal pain.9 Given the strong neurobiological connection between the brain and gut that has been phylogenetically preserved, emotional (e.g., fear, terror) or physical (e.g., pain) signals represent danger, and with chronicity, there can be a kindling-related consolidation of these maladaptive neurobiological pathways leading to suffering (e.g., hopelessness, sense of failure) and disability (Figure 1).
The interrelationship between chronic pain and trauma is multifaceted and is further complicated by the traumatizing nature of chronic pain itself, when pain is interpreted as a signal that the body is sick or even dangerously ill. Patients with chronic abdominal pain may seek multiple medical opinions and often undergo extensive, unnecessary, and sometimes harmful interventions to find the cause of their pain, with fear of disability and even death driving this search for answers.
The degree to which an individual with long-lasting pain interprets their discomfort as a risk to their well-being is related to the degree of trauma they experience because of their pain.10 Indeed, many of the negative symptoms associated with posttraumatic stress are also found in those with chronic abdominal pain. Trauma impacts the fear circuitry centers of the brain, leading to altered activation of the hypothalamic-pituitary-adrenal axis and the amygdala, as well as chronic activation of the sympathetic nervous system and stress-released hormones, all of which are potential pathways that dysregulate the brain-gut relationship.11-13 Worries for safety, which are reactivated by physiological cues (e.g., GI symptoms, pain), as well as avoidance of potential triggers of GI symptoms (e.g., food, exercise, medications, and situations such as travel or scheduled events, and fear of being trapped without bathroom access), are common. Traumatized individuals can experience a foreshortened sense of the future, which may lead to decreased investment in long-term determinants of health (e.g., balanced diet, exercise, social support) and have higher rates of functional impairment and higher health care utilization.14 Negative mood, including irritability, anxiety, depression, insomnia, and impaired concentration are common in those with trauma and chronic pain and can be accompanied by internalized blame (e.g., depression, substance abuse, suicidality) or externalized blame (e.g., negative relationships with health care providers, rejection from their support or faith system). These can be worsened by an impaired sense of trust, which impacts the patient-provider relationship and other sources of social support leading to lack of behavioral activation, anhedonia, and isolation.
Another commonality is hypervigilance, as those with chronic abdominal pain are often hyperaware of physical symptoms and always “on alert” for a signal indicative of a pain flare. Anxiety and depression frequently co-occur in populations with trauma and chronic pain; these diagnoses are associated with higher rates of catastrophizing and learned helplessness, which may be exacerbated by lack of a “cure” for functional gastrointestinal disorders (FGIDs) and chronic pain.15 These factors could potentially lead to lack of engagement with treatment or, alternatively, risky or destructive attempts to cure pain including dangerous complementary alternative treatments or substance abuse to numb sensations. Another feature of trauma in chronic pain is the sense of dissociation from and lack of control over the body, sometimes induced by negative medical experiences (e.g., unwanted physical examinations, medication side effects, traumatic procedures, or hospitalizations).16,17