Abdominal pain is often diffuse and difficult to pinpoint. That is why those affected frequently perceive it as particularly threatening. As a recent study from the Collaborative Research Center “Treatment Expectation” shows, such so-called visceral pain actually occupies a unique biological position: Using an experimental approach, a research team led by Prof. Sigrid Elsenbruch from University Hospital Essen was able to demonstrate that internal pain is particularly susceptible to strong nocebo effects. What makes this particularly tricky is that even negative experiences with entirely different types of physical pain can negatively influence the perception of visceral pain.
Dr. Jana Aulenkamp from the Department of Anesthesiology and Intensive Care Medicine at University Hospital Essen therefore concludes that healthcare providers should be particularly mindful of expectations when communicating with patients who have abdominal pain. The researchers published their findings in the renowned journal PAIN.
People with visceral pain often have negative experiences with treatment
The abdomen, intestines, and internal organs ache repeatedly. But the cause is unclear, and treatments are ineffective: Many people with chronic visceral pain have had negative experiences with diagnosis and treatment. Those affected are often frustrated - especially with communication with doctors. However, such disappointments often become entrenched as negative expectations in cases of chronic, painful, treatment-resistant conditions such as visceral pain or irritable bowel syndrome, which can increase nocebo effects.
Psychology professor Sigrid Elsenbruch, project leader in project A04 the Collaborative Research Center (SFB 289) “Treatment Expectation” at University Hospital Essen and head of the Department of Medical Psychology and Medical Sociology at Ruhr University Bochum, is researching how treatment expectations influence abdominal pain and the success of therapies. For the current study, she and her team examined 101 healthy volunteers to investigate how signals from the gut and subsequent visceral pain are perceived in comparison to somatic heat pain on the skin. Using a complex study design aligned with daily clinical practice, the team induced negative expectations in the participants and examined their effect on pain perception. Previous experiences with pain were the second factor tested as an influencing variable. This is the first experimental study to examine nocebo effects on the experience of pain originating from within the body and on the body’s surface, as well as their mutual influence.
The results have far-reaching implications
Clinician scientist Dr. med. Jana Aulenkamp, the study’s first author, summarizes the findings: “Nocebo effects are significantly more pronounced in cases of pain originating from within the body, and they can be exacerbated by communication as well as by somatic pain experiences from the body’s surface.” These findings in healthy individuals have particularly far-reaching implications for people with chronic pain, as they often experience additional symptoms in various parts of the body.
“For example, it is conceivable that another pain condition, such as back pain, upregulates the pain system, so that abdominal pain is then perceived more intensely, even if the back pain has long since subsided,” explains Prof. Elsenbruch. Experiences with other, somatic pain thus carries over to visceral pain. Dr. Aulenkamp advises: “When treating patients with visceral pain, I should be aware that it is part of the individual pain perception, that it is strongly influenced by cognition, emotion, and expectation, especially when patients suffer from various types of pain.”
The significance of the gut-brain axis
For a long time, recurring lower abdominal pain with no identifiable cause was considered a typical psychosomatic complaint primarily linked to stress. However, the connection between the mind and the gut is far more complex and, above all, not a one-way street from the head to the gut that is altered solely by stress.
There is a direct connection between the brain and the gut, known as the gut-brain axis. Communication flows in both directions along this axis. Information is transmitted as neural signals from the central nervous system via the vagus nerve, but also with the help of gut microbes, hormones, and neurotransmitters. Patients with irritable bowel syndrome, for example, show increased sensitivity to visceral stimuli and heightened pain sensitivity. This is due to disruptions in the communication pathways along the gut-brain axis. Many cognitive and emotional factors are involved in the experience of pain and its processing. Stress and anxiety can intensify nocebo effects and impair the functions of the gut-brain axis.
Effective communication in visceral pain
Effective doctor-patient communication is a crucial foundation for minimizing long-term disruption of the gut-brain axis and directly reducing the noticeable symptoms of visceral pain. “Through empathetic and attentive communication by healthcare providers, as well as by emphasizing positive treatment outcomes, the perception of pain can be effectively ‘overwritten’, at least in part,” explains Prof. Elsenbruch. The research team draws the following conclusion from the experimental study: If negative expectations regarding visceral pain are already much more relevant in healthy individuals than in cases of somatic pain, this should definitely be given greater consideration in clinical practice.
In gastroenterology, gynecology, abdominal surgery, and cardiac surgery, healthcare providers should therefore receive particularly thorough training in communication. “Clinicians should be aware that words have a much stronger impact on patients with visceral pain than on those with an injured foot,” notes Dr. Aulenkamp.