ArticleDiagnostics (Basel, Switzerland)2020
The Endogenous Opioid System in Schizophrenia and Treatment Resistant Schizophrenia: Increased Plasma Endomorphin 2, and κ and μ Opioid Receptors Are Associated with Interleukin-6.
Article in Diagnostics (Basel, Switzerland), 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 14 papers, 1 of them a synthesis that pooled it.
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Who cites it
14 citing papers in PubMed, 1 synthesis or guideline pooled it, 23 citations in OpenAlex.
- The relationship between immune and cognitive dysfunction in mood and psychotic disorder: a systematic review and a meta-analysis.Molecular psychiatry · 2022Pooled it
- Molecular Underpinning of Treatment-Resistant Schizophrenia: A Putative Different Neurobiology from Treatment-Responsive Schizophrenia.International journal of molecular sciences · 2025Review
- Neuropeptidergic systems in psychiatric disorders.Frontiers in endocrinology · 2025Review
- Biomarkers of treatment-resistant schizophrenia: A systematic review.Neuroscience applied · 2024Article
- Article
- Sex differences in the association of treatment-resistant schizophrenia and serum interleukin-6 levels.BMC psychiatry · 2023Article
- G protein-coupled receptors in neurodegenerative diseases and psychiatric disorders.Signal transduction and targeted therapy · 2023Review
- Obsessive-compulsive symptoms in patient with schizophrenia: The influence of disorganized symptoms, duration of schizophrenia, and drug resistance.Frontiers in psychiatry · 2023Article
- Cytokine Imbalance as a Biomarker of Treatment-Resistant Schizophrenia.International journal of molecular sciences · 2022Review
- Early Markers in Resistant Schizophrenia: Effect of the First Antipsychotic Drug.Diagnostics (Basel, Switzerland) · 2022Article
- Pathway Phenotypes Underpinning Depression, Anxiety, and Chronic Fatigue Symptoms Due to Acute Rheumatoid Arthritis: A Precision Nomothetic Psychiatry Analysis.Journal of personalized medicine · 2022Article
- Increased ACE2, sRAGE, and Immune Activation, but Lowered Calcium and Magnesium in COVID-19.Recent advances in inflammation & allergy drug discovery · 2022Article
- In schizophrenia, non-remitters and partial remitters to treatment with antipsychotics are qualitatively distinct classes with respect to neurocognitive deficits and neuro-immune biomarkers: results of soft independent modeling of class analogy.Metabolic brain disease · 2021Article
- Chronic fatigue syndrome and fibromyalgia-like symptoms are an integral component of the phenome of schizophrenia: neuro-immune and opioid system correlates.Metabolic brain disease · 2021Article
Corrections and comments
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Authors and funding
7 authors at 6 institutions in 4 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundactivation of the immune-inflammatory response system (IRS) and the compensatory immune-regulatory system (CIRS) plays a key role in schizophrenia (SCZ) and treatment resistant SCZ. There are only a few data on immune and endogenous opioid system (EOS) interactions in SCZ and treatment resistant SCZ.
methodswe examined serum β-endorphin, endomorphin-2 (EM2), mu-opioid (MOR) and kappa-opioid (KOR) receptors, and interleukin (IL)-6 and IL-10 in 60 non responders to treatment (NRTT), 55 partial RTT (PRTT) and 43 normal controls.
resultsserum EM2, KOR, MOR, IL-6 and IL-10 were significantly increased in SCZ as compared with controls. β-endorphin, EM2, MOR and IL-6 were significantly higher in NRTT than in PRTT. There were significant correlations between IL-6, on the one hand, and β-endorphin, EM2, KOR, and MOR, on the other, while IL-10 was significantly correlated with MOR only. A large part of the variance in negative symptoms, psychosis, hostility, excitation, mannerism, psychomotor retardation and formal thought disorders was explained by the combined effects of EM2 and MOR with or without IL-6 while increased KOR was significantly associated with all symptom dimensions. Increased MOR, KOR, EM2 and IL-6 were also associated with neurocognitive impairments including in episodic, semantic and working memory and executive functions.
conclusionthe EOS contributes to SCZ symptomatology, neurocognitive impairments and a non-response to treatment. In SCZ, EOS peptides/receptors may exert CIRS functions, whereas increased KOR levels may contribute to the pathophysiology of SCZ and EM2 and KOR to a non-response to treatment.
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