Physio-somatic symptoms in schizophrenia: association with depression, anxiety, neurocognitive deficits and the tryptophan catabolite pathway. — ME/CFS Atlas
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Physio-somatic symptoms in schizophrenia: association with depression, anxiety, neurocognitive deficits and the tryptophan catabolite pathway.
Kanchanatawan, Buranee, Sirivichayakul, Sunee, Thika, Supaksorn et al. · Metabolic brain disease · 2017 · DOI
Quick Summary
This study looked at physical symptoms like fatigue, muscle pain, and flu-like feelings in people with schizophrenia. Researchers found that more than half of schizophrenia patients experienced these symptoms, which were linked to depression, anxiety, and problems with memory and attention. The symptoms appeared to be connected to changes in how the body processes tryptophan, an amino acid, and how the immune system responds to these breakdown products.
Why It Matters
While this study focuses on schizophrenia, the findings are relevant to ME/CFS research because both conditions involve physio-somatic symptoms and potential dysregulation of the tryptophan catabolite pathway. Understanding how immune responses to tryptophan metabolites contribute to fatigue, pain, and cognitive dysfunction in one condition may illuminate similar mechanisms in ME/CFS, potentially opening new diagnostic and therapeutic avenues.
Observed Findings
Over 50% of schizophrenia patients had elevated physio-somatic symptoms (fatigue, muscle pain, autonomic and cognitive symptoms, flu-like malaise).
Physio-somatic symptoms significantly co-occurred with depression and anxiety but not with positive or negative psychotic symptoms.
Physio-somatic symptoms were associated with elevated IgA responses to 3-hydroxykynurenine, picolinic acid, and xanthurenic acid, and reduced IgA to quinolinic acid and anthranilic acid.
Physio-somatic symptoms correlated with cognitive impairments in spatial planning, working memory, paired associative learning, visual attention, and attention set shifting.
Inferred Conclusions
Physio-somatic symptoms in schizophrenia are driven partly by dysregulated immune responses to tryptophan catabolites, with differential IgA and IgM patterns reflecting mucosal and regulatory immune mechanisms.
The association between physio-somatic symptoms and cognitive deficits suggests shared neurobiological mechanisms involving tryptophan catabolite signaling and neuroglial activity.
Physio-somatic symptoms in schizophrenia cluster with affective rather than primary psychotic symptoms, suggesting distinct pathophysiological pathways.
Remaining Questions
Do tryptophan catabolite immune responses precede physio-somatic symptoms or result from them (temporal relationship and causality)?
What This Study Does Not Prove
This study does not prove that tryptophan catabolite immune responses *cause* physio-somatic symptoms—only that they are associated. The cross-sectional design cannot establish temporal relationships or directionality. The findings in schizophrenia patients may not directly apply to ME/CFS or other chronic fatigue conditions without further investigation.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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