Chronic fatigue syndrome and fibromyalgia-like symptoms are an integral component of the phenome of schizophrenia: neuro-immune and opioid system correlates. — CFSMEATLAS
Chronic fatigue syndrome and fibromyalgia-like symptoms are an integral component of the phenome of schizophrenia: neuro-immune and opioid system correlates.
Mousa, Rana Fadhil, Al-Hakeim, Hussein Kadhem, Alhaideri, Amer et al. · Metabolic brain disease · 2021 · DOI
Quick Summary
This study looked at whether people with schizophrenia experience fatigue and pain symptoms similar to ME/CFS and fibromyalgia. Researchers measured blood markers related to immune system function and found that specific immune proteins and opioid system changes were associated with these physiosomatic symptoms. The findings suggest that abnormal immune activity and changes in the body's natural pain-relieving systems may contribute to these exhaustion and pain symptoms in schizophrenia patients.
Why It Matters
This study provides evidence that ME/CFS-like symptoms in schizophrenia involve measurable immune and opioid system dysfunctions, suggesting shared biological pathways between these conditions. Understanding these mechanisms in schizophrenia may illuminate similar neuro-immune processes in ME/CFS, potentially leading to better biomarkers and targeted treatments for physiosomatic symptoms.
Observed Findings
Schizophrenia patients with higher physiosomatic symptom scores showed elevated IL-6 and HMGB1, and reduced IL-10 compared to those with lower scores.
Cognitive performance on digit sequencing, token motor tasks, and list learning was inversely correlated with physiosomatic symptom severity.
Alterations in opioid receptor markers (MOR and KOR) were among the top six predictors of physiosomatic symptom severity.
45.1% of variance in combined cognitive, psychiatric, and physiosomatic symptoms was explained by HMGB1, MOR, EM2, DKK1, and CCL11.
Inferred Conclusions
Physiosomatic symptoms (ME/CFS-like and fibromyalgia-like) are an integral component of schizophrenia phenomenology, not incidental features.
Neurotoxic immune pathways with reduced immune regulation (high IL-6, low IL-10, elevated HMGB1) coupled with endogenous opioid system dysfunction drive these physiosomatic symptoms.
The interconnection between immune dysfunction, opioid system alterations, and cognitive impairment suggests a unified neuro-immune mechanism underlying physiosomatic manifestations in schizophrenia.
Remaining Questions
Do these same immune and opioid system abnormalities occur in primary ME/CFS, and if so, are the mechanisms identical or distinct?
Is the immune activation primary (driving symptoms) or secondary (resulting from other aspects of schizophrenia), and what triggers these immune changes?
What This Study Does Not Prove
This study does not prove that schizophrenia causes ME/CFS or vice versa, nor does it establish that the immune markers directly cause the fatigue and pain symptoms—only that they are associated. The cross-sectional design cannot determine causality or the direction of relationships. Additionally, findings in schizophrenia patients may not directly apply to primary ME/CFS, which was not studied here.
Could targeting IL-6, HMGB1, or opioid receptor function reduce physiosomatic symptoms in schizophrenia, and would such interventions also help ME/CFS patients?
How do antipsychotic medications influence these immune and opioid markers, and do they contribute to or ameliorate physiosomatic symptom burden?