Related Experiment Video
Updated: Nov 12, 2025
Microbiota Analysis Using Two-step PCR and Next-generation 16S rRNA Gene Sequencing
Published on: October 15, 2019
Bugs and Brains, the Gut and Mental Health Study: a mixed-methods study investigating microbiota composition and
Carra A Simpson1,2, Orli S Schwartz3, Djamila Eliby4,2
1Melbourne School of Psychological Sciences, The University of Melbourne Faculty of Medicine Dentistry and Health Sciences, Melbourne, Victoria, Australia carra.simpson@unimelb.edu.au.
Introduction:
Research has highlighted relationships between the micro-organisms that inhabit our gastrointestinal tract (oral and gut microbiota) with host mood and gastrointestinal functioning. Mental health disorders and functional gastrointestinal disorders co-occur at high rates, although the mechanisms underlying these associations remain unclear. The Bugs and Brains Study aims to investigate complex relationships between anxiety/depression and irritable bowel syndrome (IBS) in two ways. First, its primary component will compare the gut and oral microbiota in females with anxiety/depression and/or IBS relative to controls, and investigate underlying physiological, endocrine and immune factors, as well as associations with diet and psychosocial factors. In an ancillary component, the study will also investigate gastrointestinal and mental health symptoms in a larger sample, and explore relationships with diet, exercise, oral health, substance use, medical history, early life adversity and psychosocial factors.
Methods And Analysis:
The Bugs and Brains Study aims to recruit 160 females to the primary component: (1) 40 controls; (2) 40 participants with a depressive/anxiety disorder, but no IBS; (3) 40 participants with IBS, but no depressive/anxiety disorder and (4) 40 participants with both depressive/anxiety disorder and IBS. Participation is completed within 1 month, and involves comprehensive questionnaires, anthropometrics, a diagnostic clinical interview, collection of two saliva samples, and stool, urine and hair samples. This study aims to use a systems biology approach to characterise oral and gut microbial composition and function using 16S rRNA gene sequencing and nuclear MR spectroscopy. As part of the ancillary component, it will collect questionnaire data from 1000 participants aged 18-40 years, capturing mental health, gastrointestinal health, oral health, diet and psychosocial factors.
Ethics And Dissemination:
Approval was granted by the University of Melbourne Human Research Ethics Committee (#1749221). All participants voluntarily provided informed consent. Results will be published in peer-reviewed journals and presented at scientific conferences.
Insights
The Bugs and Brains Study explores links between gut microbes, anxiety, depression, and irritable bowel syndrome (IBS) in women. Findings may reveal new insights into these interconnected health conditions.
Area of Science:
- Microbiome research
- Neurogastroenterology
- Psychiatry
Background:
- High co-occurrence rates of mental health and functional gastrointestinal disorders suggest shared underlying mechanisms.
- The precise relationship between the oral and gut microbiota, and host mood and gastrointestinal function, remains incompletely understood.
Purpose of the Study:
- To investigate the complex interplay between anxiety/depression and irritable bowel syndrome (IBS) by examining gut and oral microbiota.
- To identify physiological, endocrine, immune, dietary, and psychosocial factors associated with these conditions.
- To explore gastrointestinal and mental health symptoms in relation to lifestyle and historical factors in a larger cohort.
Main Methods:
- Primary component: 160 females (controls, anxiety/depression, IBS, or both) undergo clinical interviews, questionnaires, and sample collection (saliva, stool, urine, hair).
- Systems biology approach using 16S rRNA gene sequencing and nuclear MR spectroscopy to characterize microbial composition and function.
- Ancillary component: 1000 participants (aged 18-40) provide questionnaire data on mental, gastrointestinal, oral health, diet, and psychosocial factors.
Main Results:
- N/A - Study is ongoing, results not yet available.
Conclusions:
- N/A - Study is ongoing, conclusions not yet available.
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