(Unexplained) Persistent Physical Symptoms (PPS): Definition, Causes, and Treatment

(Unexplained) Persistent Physical Symptoms (PPS): Definition, Causes, and Treatment

A Lancet article, titled “Persistent physical symptoms: definition, genesis, and management” (Lowe, 2024), provided a comprehensive overview of how long-term somatic complaints—often called “medically unexplained symptoms (MUPS)”—should be understood and treated.

The key points of the article are as follows:

1. Defining “Persistent Physical Symptoms” (PPS)

• Umbrella Term: PPS refers to distressing somatic complaints (like pain, fatigue, or dizziness) that last for several months or more.

• Agnostic to Cause: The term applies regardless of whether the symptoms are linked to a known disease (like rheumatoid arthritis) or arise without a clear structural cause (like fibromyalgia or functional dyspepsia).

• Impact: These symptoms are a major cause of disability, high healthcare costs, and emotional distress globally.

2. Causes: Why Symptoms Persist

The article moves away from the old “all in the head” vs. “all in the body” debate, using a biopsychosocial vulnerability–stress model:

• Predisposing Factors: These include genetics, early adverse life experiences (trauma), and personality traits like illness-related anxiety.

• Triggering Factors: Acute triggers often include infections (e.g., Long COVID), physical injuries, or high-stress life events.

• Maintaining Factors: These are what keep the symptoms going long after the initial trigger is gone. They include:

  • Biological: Persistent low-grade inflammation and dysregulation of the nervous, immune, or metabolic systems.

  • Cognitive/Perceptual: “Predictive coding” errors where the brain becomes overly sensitive to body signals, amplifying minor sensations into intense pain or distress.

  • Behavioral: Avoidance of activity (deconditioning) or dysfunctional healthcare-seeking behaviors.

3. Challenges in the Healthcare System

• Stigma: Patients often feel disbelieved or dismissed when tests come back “normal,” leading to a breakdown in the doctor-patient relationship.

• Siloed Care: Medical systems are often split between “physical” and “mental” health, which fails patients whose symptoms cross these boundaries.

4. Management and Treatment 

The article advocates for a tiered approach to care:

• Validation and Communication: The first step is for doctors to validate the patient’s experience. Using “biopsychosocial explanations” helps patients understand that their symptoms are real and caused by complex biological-psychological interactions, not “imaginary.”

• Basic Care: Addressing underlying pathophysiology while providing appropriate reassurance and avoiding unnecessary, invasive testing.

• Specialised Care: If symptoms persist, the article recommends:

  • Psychological Interventions: Cognitive Behavioral Therapy (CBT) or Mindfulness to address symptom focusing and catastrophizing.

  • Pharmacological: Using medications (like certain antidepressants) that act on the central nervous system to “dial down” pain signals.

  • Multidisciplinary Teams: Coordination between GPs, specialists, psychologists, and physiotherapists.

5. Call to Action

The authors argue that PPS should be recognized as a major public health priority. They call for:

• Curriculum Reform: Training medical students in symptom perception and the biopsychosocial model.

• Increased Funding: More research into the mechanisms of symptom persistence to develop “mechanism-based” treatments.

• Neutral Coding: Developing diagnostic codes that don’t force a choice between “mental” and “physical” causes, reducing stigma.