ArticleBipolar disorders2018
Total sleep time and kynurenine metabolism associated with mood symptom severity in bipolar disorder.
Article in Bipolar disorders, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 24 papers, 5 of them syntheses that pooled it.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
24 citing papers in PubMed, 5 syntheses or guidelines pooled it, 47 citations in OpenAlex.
- Sleep abnormalities in bipolar disorders across mood phases: A systematic review and meta-analysis.Sleep medicine reviews · 2025Pooled it
- Toward a Digital Future in Bipolar Disorder Assessment: A Systematic Review of Disruptions in the Rest-Activity Cycle as Measured by Actigraphy.Frontiers in psychiatry · 2022Pooled it
- The kynurenine pathway in major depressive disorder, bipolar disorder, and schizophrenia: a meta-analysis of 101 studies.Molecular psychiatry · 2021Pooled it
- The kynurenine pathway in bipolar disorder: a meta-analysis on the peripheral blood levels of tryptophan and related metabolites.Molecular psychiatry · 2021Pooled it
- Tryptophan Catabolites in Bipolar Disorder: A Meta-Analysis.Frontiers in immunology · 2021Pooled it
- Kynurenine pathway dysregulation in major depressive disorder: the convergence of excitotoxicity, neuroinflammation, and oxidative stress.Journal of neuroinflammation · 2026Review
- The kynurenine pathway in depression and schizophrenia: convergent signals, divergent states, and clinical signatures.EXCLI journal · 2026Review
- Neurochemical Insights into the Role of Tryptophan Metabolites and Kynurenine Pathway in Insomnia and its Psychological and Neurological Comorbidities.Molecular neurobiology · 2025Review
- Reducing brain kynurenic acid synthesis precludes kynurenine-induced sleep disturbances.Journal of sleep research · 2024Article
- Serum neuroactive metabolites of the tryptophan pathway in patients with acute phase of affective disorders.Frontiers in psychiatry · 2024Article
- Sleep, mood disorders, and the ketogenic diet: potential therapeutic targets for bipolar disorder and schizophrenia.Frontiers in psychiatry · 2024Review
- Inflammation and emotion regulation: a narrative review of evidence and mechanisms in emotion dysregulation disorders.Neuronal signaling · 2023Review
- Kynurenine aminotransferase II inhibition promotes sleep and rescues impairments induced by neurodevelopmental insult.Translational psychiatry · 2023Article
- A bibliometric analysis of the studies in high-altitude induced sleep disturbances and cognitive impairment research.Frontiers in physiology · 2023Article
- The tryptophan catabolite or kynurenine pathway in major depressive and bipolar disorder: A systematic review and meta-analysis.Brain, behavior, & immunity - health · 2022Review
- The association of kynurenine pathway metabolites with symptom severity and clinical features of bipolar disorder: An overview.European psychiatry : the journal of the Association of European Psychiatrists · 2022Review
- Temporal relationships of ecological momentary mood and actigraphy-based sleep measures in bipolar disorder.Journal of psychiatric research · 2022Article
- Is Poor Lithium Response in Individuals with Bipolar Disorder Associated with Increased Degradation of Tryptophan along the Kynurenine Pathway? Results of an Exploratory Study.Journal of clinical medicine · 2022Article
- Metabolomics: Impact of Comorbidities and Inflammation on Sickness Behaviors for Individuals with Chronic Wounds.Advances in wound care · 2021Review
- Lipophilic vs. hydrophilic statins and psychiatric hospitalizations and emergency room visits in US Veterans with schizophrenia and bipolar disorder.Pteridines · 2021Article
Corrections and comments
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Authors and funding
9 authors at 6 institutions in 3 countries.
Funding
Abstract
objectiveChronic, low-level inflammation is associated with symptomatic bipolar disorder (BD) and with chronic insomnia. Disrupted sleep is a feature of episodes of both mania and depression. We examined the effect of neopterin, a marker of cellular immune activation, and kynurenine (KYN), an inflammatory byproduct of the serotonin pathway, on the association between total sleep time and depression severity in BD.
methodTwenty-one symptomatic BD participants and 28 healthy controls (HC) were recruited and followed during usual clinical care. At baseline and after symptomatic recovery, total sleep time was objectively measured with actigraphy for 1 week and blood plasma was collected to measure the serotonin precursor tryptophan (TRP), KYN, the KYN/TRP ratio, and neopterin levels. Statistical analyses were conducted using chi-square, independent t tests and hierarchical linear multiple regression models.
resultsTotal sleep time was correlated positively with depressive severity and negatively with manic severity. TRP was significantly reduced in BD participants compared to HC. KYN, TRP, and the KYN/TRP ratio were associated with depressive severity when total sleep time and body mass index (BMI) were included in the model. The KYN/TRP ratio trended towards a negative association with mania symptoms, controlling for BMI and total sleep time, in acutely symptomatic BD participants. Neopterin was not associated with sleep or mood severity. After usual clinical care, BD participants showed significantly decreased clinical symptoms but no significant differences in sleep phenotype or biomarkers.
conclusionInflammation, sleep, and mood are closely intertwined. Future research into the effect of inflammation on sleep in BD may lead to clinical markers of outcome.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.