ReviewInternational journal of molecular sciences2022
Tryptophan Metabolism in Depression: A Narrative Review with a Focus on Serotonin and Kynurenine Pathways.
Review in International journal of molecular sciences, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 173 papers, 5 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
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.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
173 citing papers in PubMed, 5 syntheses or guidelines pooled it, 284 citations in OpenAlex.
- The Impact of Chronic Stress on Treatment Outcomes of Cancer Patients with Divergent Survival Rates: A Systematic Review.International journal of molecular sciences · 2026Pooled it
- Antidepressant effects and therapeutic potential of naringenin: a systematic review and meta-analysis of preclinical studies.Frontiers in pharmacology · 2026Pooled it
- Association between maternal asthma and ASD/ADHD in offspring: A meta-analysis based on observational studies.NPJ primary care respiratory medicine · 2025Pooled it
- A sum of its parts: A systematic review evaluating biopsychosocial and behavioral determinants of perinatal depression.PloS one · 2024Pooled it
- Sex Differences in Tryptophan Metabolism: A Systematic Review Focused on Neuropsychiatric Disorders.International journal of molecular sciences · 2023Pooled it
- Nutraceutical Blends Promote Weight Loss, Inflammation Reduction, and Better Sleep: The Role of Faecalibacterium prausnitzii in Overweight Adults-A Double-Blind Trial.Molecular nutrition & food research · 2025Trial
- SunGold Kiwifruit and Psychological Health (GoKiPH): A Randomised Controlled Crossover Trial.Nutrients · 2025Trial
- The effect of prebiotic supplementation on serum levels of tryptophan and kynurenine in obese women with major depressive disorder: a double-blinded placebo-controlled randomized clinical trial.BMC research notes · 2024Trial
- Effects of three-duration Tai-Chi exercises on depression and sleep quality in older women.European geriatric medicine · 2024Trial
- Trial
- Article
- The Tryptophan-Kynurenine Pathway as a Key Mediator of the Gut-Brain Axis in Depression and Alzheimer's Disease.International journal of molecular sciences · 2026Review
- Virobiome-mediated regulation of microbiota-gut-brain axis signaling and neuroimmune homeostasis.Cell communication and signaling : CCS · 2026Review
- Brains, quacks, and boojums: a review of neurotransmitter and neuroendocrine bases of welfare and enrichment in poultry with an emphasis on the Pekin duck.Poultry science · 2026Review
- Metabolic shifts driven by host-microbial interactions.The FEBS journal · 2026Review
- Therapeutic potential of CMPP, a novel maleimide derivative, in a reserpine-induced mouse model of pain-depression dyad.Biochemistry and biophysics reports · 2026Article
- Serotonin neuromicrobiology: Psychobiotic modulation of the gut-brain axis for mental health.Ibrain · 2026Review
- Erythritol Exacerbates DSS-Induced Colitis and Influences Behavioral Responses in Mice Through Gut Microbiota and Metabolic Alterations.Microorganisms · 2026Article
- Unveiling the enigma of anxiety disorders and depression: from pathogenesis to treatment.Science China. Life sciences · 2026Review
- Seasonal Affective Disorder and the Microbiota-Gut-Brain Axis: Circadian Disruption, Tryptophan Metabolism, and Psychobiotic Potential ofNutrients · 2026Review
113 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
2 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Depression is a common and serious disorder, characterized by symptoms like anhedonia, lack of energy, sad mood, low appetite, and sleep disturbances. This disease is very complex and not totally elucidated, in which diverse molecular and biological mechanisms are involved, such as neuroinflammation. There is a high need for the development of new therapies and gaining new insights into this disease is urgent. One important player in depression is the amino acid tryptophan. This amino acid can be metabolized in two important pathways in the context of depression: the serotonin and kynurenine pathways. These metabolic pathways of tryptophan are crucial in several processes that are linked with depression. Indeed, the maintenance of the balance of serotonin and kynurenine pathways is critical for the human physiological homeostasis. Thus, this narrative review aims to explore tryptophan metabolism (particularly in the serotonin and kynurenine pathways) in depression, starting with a global overview about these topics and ending with the focus on these pathways in neuroinflammation, stress, microbiota, and brain-derived neurotrophic factor regulation in this disease. Taken together, this information aims to clarify the metabolism of tryptophan in depression, particularly the serotonin and kynurenine pathways.
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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 Socratic graph.