Major Depressive Disorder (MDDNCT07634458
Serotonin Variants & Gut Microbiota in Mental Health
An observational study of Major Depressive Disorder (MDD and Anxiety Disorder, Generalized, run by Neurobiologix.
Trial summary
This observational pilot study investigates whether a broad panel of genetic variants relevant to the serotonin pathway (including serotonergic system, methylation cycle, intestinal barrier integrity, and inflammatory response genes) are associated with distinct gut microbiome compositional and functional signatures… Read more about this study
- Who is it for?
- Ages 18 to 44 years
- Conditions the study is for
- Major Depressive Disorder (MDD, Anxiety Disorder, Generalized, Stress Disorders, Post-Traumatic
- What is being tested?
- SNP Genotyping and Gut Metagenomics
- How many people
- 30 participants
- Where
- No sites listed yet
- Study dates
- 1 Jul 2026to Sep 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 44 years
- All sexes
- Adult
Study population: US adults aged 18-44 years with self-reported MDD, GAD, PTSD, or Panic Disorder. Recruited via Neurobiologix and Tiny Health digital platforms and social media. Decentralized, direct-to-participant model.
Who may be able to join
- Age: Adults aged 18 to 44 years.
- Residency: Current legal residents of the United States.
- Clinical Phenotype: Self-report of Major Depressive Disorder (MDD), Generalized Anxiety Disorder (GAD), Post-Traumatic Stress Disorder (PTSD), or Panic Disorder.
- Medication Stability: If currently prescribed psychotropic medications (e.g., SSRIs, SNRIs, benzodiazepines), the dosage must remain stable with no changes in molecule or quantity for at least 3 months prior to enrollment.
- Language and Technology: Proficiency in English and access to a smartphone or computer for digital data entry.
- Financial Commitment: Explicit agreement to the "Citizen Science" model, including payment for discounted testing kits. Kit shipping (both directions) is prepaid by the study.
Who cannot join
- Use of systemic antibiotics, antifungals, or antivirals within the 8 weeks prior to specimen collection.
- Regular use of commercial probiotics or concentrated prebiotic supplements within 4 weeks of collection.
- Frequent use of osmotic or stimulant laxatives, or motility agents, within 4 weeks of collection.
- Chronic use (>3 times/week) of NSAIDs, systemic corticosteroids, or high-dose Omega-3 supplementation (>2g/day) within 4 weeks of enrollment.
- Use of weight-loss medications or GLP-1 receptor agonists (e.g., semaglutide, liraglutide, tirzepatide) within the 3 months prior to enrollment.
- Confirmed diagnosis of Irritable Bowel Syndrome (IBS), Inflammatory Bowel Disease (Crohn's or Ulcerative Colitis), Celiac Disease, or history of major gastric/intestinal resection.
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- Current pregnancy or lactation.
- Presence of cognitive impairments that preclude the ability to provide informed consent.
- Individuals undergoing active cancer treatment.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Association Between Serotonin Pathway Genetic Variants and Tryptophan-Metabolizing Gut Microbiota in Adults With Mental Health Conditions: An Observational Pilot Study
This observational pilot study investigates whether a broad panel of genetic variants relevant to the serotonin pathway (including serotonergic system, methylation cycle, intestinal barrier integrity, and inflammatory response genes) are associated with distinct gut microbiome compositional and functional signatures in adults aged 18-44 years with self-reported mental health conditions (Major Depressive Disorder, Generalized Anxiety Disorder, PTSD, or Panic Disorder).
This is a decentralized, participant-funded (Citizen Science) study. Eligible participants provide at-home saliva (buccal swab) and stool samples. Genomic analysis is performed using the NeuroBiologix GenePro+ SNP Panel (Illumina Infinium Global Screening Array-24, ~654,000 SNPs) via Gene By Gene, a CLIA/CAP-accredited laboratory. Gut microbiome analysis is performed by Tiny Health using deep whole-genome shotgun metagenomics (≥20 million reads) on a NextGen Illumina Platform.
The study is non-interventional and hypothesis-generating, aiming to identify potential genotype-microbiome associations and estimate effect sizes to inform a future interventional trial. N=30 participants. Study Start: July 2026.
Read the detailed description
Background: The gut-brain-microbiota axis (GBA) represents a complex, bidirectional communication system. Microbial tryptophan metabolism is a key mechanism within this axis - approximately 95% of the body's serotonin is synthesized peripherally in the gut. Host genetic variants can influence both serotonin biology and gut microbiome composition.
Objective: To explore correlations between multi-system genetic variants (TPH2, SLC6A4, MTHFR, FUT2, MUC1, IL-6, and others) and gut microbiome compositional and functional profiles (particularly tryptophan metabolism pathways) in adults with self-reported mental health conditions.
Design: Decentralized observational pilot study. Participants complete digital questionnaires and provide at-home biospecimen collections (saliva and stool) using prepaid medical-grade kits.
Genomic Methodology: Saliva samples undergo DNA extraction and array-based genotyping (Illumina GSA-24 v3.0) at Gene By Gene (CLIA No. 45D1102202, CAP-accredited). Data processed via OmicsEdge bioinformatics platform.
Metagenomic Methodology: Stool samples analyzed by Tiny Health using whole-genome shotgun metagenomics. Human reads are depleted against GRCh38. Taxonomic profiling via GTDB/GenBank database (111,000+ genomes). Functional annotation via KEGG Orthology and CAZy.
Statistical Analysis: Descriptive statistics; alpha diversity (Shannon index); beta diversity (Bray-Curtis dissimilarity); PERMANOVA; exploratory non-parametric comparisons between genotype-defined groups. Effect sizes calculated for future study design.
IRB: Approved by Sterling Institutional Review Board (Atlanta, GA), IRB ID 16153.
- Conditions
- Major Depressive Disorder (MDD, Anxiety Disorder, Generalized, Stress Disorders, Post-Traumatic, Panic Disorder
- Being tested
- SNP Genotyping and Gut Metagenomics
- Keywords
- gut microbiome, serotonin, tryptophan metabolism, metagenomics, SNP genotyping, gut-brain axis
- Medical subject headings
- Depressive Disorder, Major, Generalized Anxiety Disorder, Stress Disorders, Post-Traumatic, Panic Disorder
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
SNP Genotyping and Gut MetagenomicsDiagnostic test
Genomic analysis using NeuroBiologix GenePro+ SNP Panel: Illumina Infinium Global Screening Array-24 v3.0 (~654,000 SNPs), genotyped at Gene By Gene (CLIA No. 45D1102202, CAP-accredited). Data processed via OmicsEdge bioinformatics platform analyzing serotonergic, methylation, intestinal barrier, and inflammatory pathway variants. Gut microbiome analysis using Tiny Health deep whole-genome shotgun metagenomics (NextGen Illumina Platform, ≥20 million reads), with taxonomic profiling (GTDB/GenBank) and functional annotation (KEGG Orthology, CAZy).
| Study group | Role | What they receive |
|---|---|---|
| Adults with Mental Health Conditions | US adults aged 18-44 years with self-reported MDD, GAD, PTSD, or Panic Disorder who are on stable psychotropic medication (or unmedicated). Participants provide at-home saliva and stool samples for genomic SNP analysis (NeuroBiologix GenePro+ SNP Panel) and gut microbiome shotgun metagenomics sequencing (Tiny Health platform). Receives: Diagnostic Test: SNP Genotyping and Gut Metagenomics |
What is being measured
The primary outcome is the main question the study is designed to answer.
Gut Microbiome Compositional and Functional Profile
Shotgun metagenomic sequencing of stool samples to assess gut microbial taxonomic composition (alpha and beta diversity) and functional potential, specifically tryptophan metabolism pathways (KEGG Orthology), and their association with host genetic variants in the serotonin pathway.
Measured: At study completion (approximately 8-12 weeks after enrollment)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Jun 2026
- Study start1 Jul 2026 (estimated)
- Primary completionJul 2027 (estimated)
- Study completionSep 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Major Depressive Disorder (MDDStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Neurobiologix
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07634458
- Sponsor's protocol ID
- 16153
- Status last verified
- Jun 2026
- First submitted
- 4 Jun 2026
- Last updated
- 10 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- Individual data sharing
- No: Individual participant data will not be shared due to the sensitive nature of genomic and mental health data. De-identified aggregate data and findings will be reported in peer-reviewed publications.
Study at a glance
From the registry record, last updated by the sponsor on 10 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Association Between Serotonin Pathway Genetic Variants and Tryptophan-Metabolizing Gut Microbiota in Adults With Mental Health Conditions: An Observational Pilot Study
- ClinicalTrials.gov ID
- NCT07634458
- Acronym / sponsor ID
- 16153
- Conditions
- Major Depressive Disorder (MDD, Anxiety Disorder, Generalized, Stress Disorders, Post-Traumatic, Panic Disorder
- Keywords
- gut microbiome, serotonin, tryptophan metabolism, metagenomics, SNP genotyping, gut-brain axis
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- NeurobiologixIndustry (pharma, biotech, devices)
- Study start
- 1 Jul 2026 (estimated)
- Primary completion
- Jul 2027 (estimated)
- Study completion
- Sep 2027 (estimated)
- First posted
- 8 Jun 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This observational pilot study investigates whether a broad panel of genetic variants relevant to the serotonin pathway (including serotonergic system, methylation cycle, intestinal barrier integrity, and inflammatory response genes) are associated with distinct gut microbiome compositional and functional signatures in adults aged 18-44 years with self-reported mental health conditions (Major Depressive Disorder, Generalized Anxiety Disorder, PTSD, or Panic Disorder).
This is a decentralized, participant-funded (Citizen Science) study. Eligible participants provide at-home saliva (buccal swab) and stool samples. Genomic analysis is performed using the NeuroBiologix GenePro+ SNP Panel (Illumina Infinium Global Screening Array-24, ~654,000 SNPs) via Gene By Gene, a CLIA/CAP-accredited laboratory. Gut microbiome analysis is performed by Tiny Health using deep whole-genome shotgun metagenomics (≥20 million reads) on a NextGen Illumina Platform.
The study is non-interventional and hypothesis-generating, aiming to identify potential genotype-microbiome associations and estimate effect sizes to inform a future interventional trial. N=30 participants. Study Start: July 2026.
Detailed description
Background: The gut-brain-microbiota axis (GBA) represents a complex, bidirectional communication system. Microbial tryptophan metabolism is a key mechanism within this axis - approximately 95% of the body's serotonin is synthesized peripherally in the gut. Host genetic variants can influence both serotonin biology and gut microbiome composition.
Objective: To explore correlations between multi-system genetic variants (TPH2, SLC6A4, MTHFR, FUT2, MUC1, IL-6, and others) and gut microbiome compositional and functional profiles (particularly tryptophan metabolism pathways) in adults with self-reported mental health conditions.
Design: Decentralized observational pilot study. Participants complete digital questionnaires and provide at-home biospecimen collections (saliva and stool) using prepaid medical-grade kits.
Genomic Methodology: Saliva samples undergo DNA extraction and array-based genotyping (Illumina GSA-24 v3.0) at Gene By Gene (CLIA No. 45D1102202, CAP-accredited). Data processed via OmicsEdge bioinformatics platform.
Metagenomic Methodology: Stool samples analyzed by Tiny Health using whole-genome shotgun metagenomics. Human reads are depleted against GRCh38. Taxonomic profiling via GTDB/GenBank database (111,000+ genomes). Functional annotation via KEGG Orthology and CAZy.
Statistical Analysis: Descriptive statistics; alpha diversity (Shannon index); beta diversity (Bray-Curtis dissimilarity); PERMANOVA; exploratory non-parametric comparisons between genotype-defined groups. Effect sizes calculated for future study design.
IRB: Approved by Sterling Institutional Review Board (Atlanta, GA), IRB ID 16153.
Study design
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Adults with Mental Health Conditions | – | Diagnostic Test: SNP Genotyping and Gut MetagenomicsUS adults aged 18-44 years with self-reported MDD, GAD, PTSD, or Panic Disorder who are on stable psychotropic medication (or unmedicated). Participants provide at-home saliva and stool samples for genomic SNP analysis (NeuroBiologix GenePro+ SNP Panel) and gut microbiome shotgun metagenomics sequencing (Tiny Health platform). |
Who may qualify
- Ages
- 18 to 44 years
- Sex
- All
- Age groups
- Adult
- Study population
- US adults aged 18-44 years with self-reported MDD, GAD, PTSD, or Panic Disorder. Recruited via Neurobiologix and Tiny Health digital platforms and social media. Decentralized, direct-to-participant model.
Key inclusion criteria (6 listed)
- Age: Adults aged 18 to 44 years.
- Residency: Current legal residents of the United States.
- Clinical Phenotype: Self-report of Major Depressive Disorder (MDD), Generalized Anxiety Disorder (GAD), Post-Traumatic Stress Disorder (PTSD), or Panic Disorder.
- Medication Stability: If currently prescribed psychotropic medications (e.g., SSRIs, SNRIs, benzodiazepines), the dosage must remain stable with no changes in molecule or quantity for at least 3 months prior to enrollment.
- Language and Technology: Proficiency in English and access to a smartphone or computer for digital data entry.
Key exclusion criteria (9 listed)
- Use of systemic antibiotics, antifungals, or antivirals within the 8 weeks prior to specimen collection.
- Regular use of commercial probiotics or concentrated prebiotic supplements within 4 weeks of collection.
- Frequent use of osmotic or stimulant laxatives, or motility agents, within 4 weeks of collection.
- Chronic use (>3 times/week) of NSAIDs, systemic corticosteroids, or high-dose Omega-3 supplementation (>2g/day) within 4 weeks of enrollment.
- Use of weight-loss medications or GLP-1 receptor agonists (e.g., semaglutide, liraglutide, tirzepatide) within the 3 months prior to enrollment.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| SNP Genotyping and Gut MetagenomicsGenomic analysis using NeuroBiologix GenePro+ SNP Panel: Illumina Infinium Global Screening Array-24 v3.0 (~654,000 SNPs), genotyped at Gene By Gene (CLIA No. 45D1102202, CAP-accredited). Data processed via OmicsEdge bioinformatics platform analyzing serotonergic, methylation, intestinal barrier, and inflammatory pathway variants. Gut microbiome analysis using Tiny Health deep whole-genome shotgun metagenomics (NextGen Illumina Platform, ≥20 million reads), with taxonomic profiling (GTDB/GenBank) and functional annotation (KEGG Orthology, CAZy). | Diagnostic test | Adults with Mental Health Conditions |
Primary outcome
Gut Microbiome Compositional and Functional Profile
Time frame: At study completion (approximately 8-12 weeks after enrollment)
Shotgun metagenomic sequencing of stool samples to assess gut microbial taxonomic composition (alpha and beta diversity) and functional potential, specifically tryptophan metabolism pathways (KEGG Orthology), and their association with host genetic variants in the serotonin pathway.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Jun 2026.
- Individual participant dataSharing planned: No. Individual participant data will not be shared due to the sensitive nature of genomic and mental health data. De-identified aggregate data and findings will be reported in peer-reviewed publications.
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Questions about this trial
What is this clinical trial studying?
An observational study of Major Depressive Disorder (MDD and Anxiety Disorder, Generalized, run by Neurobiologix.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 10 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Priscila Arbex, Ph.D., M.S., PG Cert. (737-400-5726, parbex@neurobiologix.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Gut Microbiome Compositional and Functional Profile (time frame: At study completion (approximately 8-12 weeks after enrollment)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Jun 2026.