ClinicalTrials.gg
Not yet recruitingNCT07634458Updated Jun 10, 2026

Serotonin Variants & Gut Microbiota in Mental Health

An observational study in Major Depressive Disorder (MDD, Anxiety Disorder, Generalized and Stress Disorders, Post-Traumatic, sponsored by Neurobiologix. Not yet recruiting. Open to participants aged 18 Years to 44 Years. Per ClinicalTrials.gov, last updated 2026-06-10.

Sponsored by Neurobiologix · Observational

Study type
Observational
Model
Cohort
Time perspective
Cross-sectional
Enrollment
30
Ages
18 Years to 44 Years
Sex
All
01

Study 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 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.

02

Conditions studied

  • 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
03

In context

Depressive Disorder, Major

3,041 studies on the registry are indexed under Depressive Disorder, Major; 588 are open to participants now.

This study's planned enrollment of 30 is below the median of 131 across 400 observational studies indexed under Depressive Disorder, Major.

Browse Depressive Disorder, Major studies →

Lead sponsor

This is the only study on the registry with Neurobiologix as lead sponsor.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 44 Years
Sexes eligible
All
Sampling method
Non-probability sample

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.

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  1. Age: Adults aged 18 to 44 years.
  2. Residency: Current legal residents of the United States.
  3. Clinical Phenotype: Self-report of Major Depressive Disorder (MDD), Generalized Anxiety Disorder (GAD), Post-Traumatic Stress Disorder (PTSD), or Panic Disorder.
  4. 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.
  5. Language and Technology: Proficiency in English and access to a smartphone or computer for digital data entry.
  6. Financial Commitment: Explicit agreement to the "Citizen Science" model, including payment for discounted testing kits. Kit shipping (both directions) is prepaid by the study.

Exclusion criteria

Exclusion Criteria:

  1. Use of systemic antibiotics, antifungals, or antivirals within the 8 weeks prior to specimen collection.
  2. Regular use of commercial probiotics or concentrated prebiotic supplements within 4 weeks of collection.
  3. Frequent use of osmotic or stimulant laxatives, or motility agents, within 4 weeks of collection.
  4. Chronic use (>3 times/week) of NSAIDs, systemic , or high-dose Omega-3 supplementation (>2g/day) within 4 weeks of enrollment.
  5. Use of weight-loss medications or GLP-1 receptor agonists (e.g., semaglutide, liraglutide, tirzepatide) within the 3 months prior to enrollment.
  6. Confirmed diagnosis of Irritable Bowel Syndrome (IBS), Inflammatory Bowel Disease (Crohn's or Ulcerative Colitis), Celiac Disease, or history of major gastric/intestinal resection.
  7. Current pregnancy or lactation.
  8. Presence of cognitive impairments that preclude the ability to provide .
  9. Individuals undergoing active cancer treatment.
Terms in these criteria, in plain language(2)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Corticosteroids (steroids)

Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.

Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

05

Study design

Observational model
Cohort
Time perspective
Cross-sectional
Enrollment
30 participants (estimated)
Patient registry
No

Groups and cohorts

  • 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).

    Diagnostic Test: SNP Genotyping and Gut Metagenomics

Interventions

  • Diagnostic testSNP Genotyping and Gut Metagenomics

    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).

06

What researchers measure

Primary outcomes

  1. 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.

    Time frame: At study completion (approximately 8-12 weeks after enrollment)

07

Study locations

No study locations are listed for this record.

08

References and documents

Individual participant data

Plan to share: 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.

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jun 10, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT07634458
Lead sponsor
Neurobiologix
Responsible party
Sponsor
First posted
Jun 8, 2026
Start date
Jul 1, 2026 (estimated)
Primary completion
Jul 2027 (estimated)
Completion
Sep 2027 (estimated)
Last update
Jun 10, 2026

Study contacts

Priscila Arbex, Ph.D., M.S., PG Cert.
Contact
parbex@neurobiologix.com
737-400-5726

Oversight

Data monitoring committee
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is not yet recruiting, as verified in Jun 2026. You cannot join it, but the record below documents what was studied.

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