Every doctor encounters patients who complain of symptoms without identifiable physical causes. According to a recent review in The Lancet, one third of all symptoms lack somatic explanations.
How can these patients be helped, and what crucial question should always be asked? This news organization discussed this topic with Professor Peter Henningsen, a coauthor of the review, at the German Congress for Psychosomatic Medicine and Psychotherapy. Dr. Henningsen is the director of the Clinic and Polyclinic for Psychosomatic Medicine and Psychotherapy at the University Hospital Rechts der Isar of the Technical University of Munich, Munich, Germany.
One Common Factor
Patients often experience a wide range of symptoms that appear without any obvious cause. These symptoms include persistent pain, dizziness, cardiovascular complaints, digestive disorders, gait disturbances, exhaustion, and fatigue. There’s often a notable gap between perceived distress and the impairment of a patient’s physical functions and examination findings.
In recent years, a descriptive umbrella term has emerged for these health challenges: persistent physical symptoms. This term includes functional physical complaints lasting for months or longer without a clearly identifiable organic cause, such as chronic fatigue syndrome, irritable bowel syndrome, fibromyalgia, or multiple chemical sensitivity. It also encompasses persistent complaints in patients with an underlying condition.
According to the review, 70% of people with chronic kidney disease experience fatigue; 63% of patients with coronary artery disease have persistent pain in their arms, legs, or joints; and 31% of patients with ulcerative colitis in remission report persistent gastrointestinal symptoms.
In International Classification of Diseases (ICD), 10th Revision, the term “somatoform disorders” is used when no organic causes are identifiable. However, ICD-11 has replaced this term with the category of “somatic symptom disorders.”
“For this diagnosis, it is no longer necessary to rule out physical causes entirely,” explained Dr. Henningsen. “Instead, the focus is on psychologic and behavioral abnormalities, anxiety, increased attention to symptoms, frequent doctor consultations, and the conviction of having a serious physical illness.”
This new diagnostic approach is considered sensible because it focuses on the patient’s experience of their illness. However, it has also been criticized for potentially “psychiatrizing” patients with genuine physical ailments.
The ‘Prediction Machine’
Understanding the new model is crucial. “It’s about grasping what is happening with a person who persistently complains of physical symptoms,” said Dr. Henningsen.
Previously, the bottom-up model of perception, which started from the pain stimulus, was widely accepted. It was believed that pain could secondarily cause psychological symptoms. However, the role of the brain has now come to the forefront. Terms like “predictive processing” or “predictive coding” are key: The brain constantly makes predictions about the most likely interpretation of sensory impressions.
These predictions incorporate expectations, beliefs, and past experiences with symptoms, which unconsciously influence these predictions. Therefore, expectations play a role in perception for all patients regardless of whether they have an organic precondition. This phenomenon can result in patients experiencing symptoms despite minimal or no sensory input.
“Perception is always biopsychosocial,” Dr. Henningsen emphasized, and diseases are not strictly physical or psychological but rather a combination of both. The proportions of these components vary, especially in chronic illnesses, where expectations play a more significant role in pain perception than they do in fresh injuries. Because predictive processing is a general mechanism of perception, it can be involved in various diseases.
The good news is that many factors contributing to persistent physical symptoms, such as increased attention to symptoms, dysfunctional expectations, or avoidance behavior, can be positively influenced.