The Effects of Probiotic Supplementation on State and Trait Stress, Anxiety, and Depression Symptoms in Stressed Adults

Not Applicable

Completed

• Conditions: Anxiety Symptoms; Perceived Stress; Depressive Symptoms

• Registration Number: NCT07216729
• Lead Sponsor: University of Colorado, Boulder

Brief Summary

The goal of this randomized controlled trial is to learn if supplementation with the probiotic Lactobacillus reuteri DSM 17938 can reduce levels of trait and state perceived stress, anxiety, and depressive symptoms compared to a placebo in a population of stressed adults ages 18-45. This study also investigates several evidence-based moderators of treatment effects, evaluates whether the probiotic caused side effects, and evaluates whether effects endured at 1-month post-supplementation.

Detailed Description

Not available

Study Timeline

• Study Start: 2023-02-20
• Primary Completion: 2024-05-06
• Study Completion: 2024-06-01
• Study First Submitted: 2025-10-10
• Study First Submitted QC: 2025-10-10
• Study First Posted: 2025-10-15
• Status Verified: 2025-11
• Last Update Submitted: 2025-11-14
• Last Update Posted: 2025-11-18

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 150

Inclusion Criteria

• age 18 - 45
• scoring 14+ on the perceived stress scale-10 indicating medium stress or higher
• ability to provide informed consent
• willingness not to take probiotic supplements (pills, tablets, oils, etc.) other than the product provided in the clinical study until all study procedures are completed
• own a smartphone and are willing to receive study materials and complete study procedures by text

Exclusion Criteria

• a history of gastrointestinal discomfort or surgery, urinary incontinence, cancer, toxic shock syndrome, frequent diarrhea, vital signs outside of the acceptable range (i.e., blood pressure >160/100, oral temperature >100°F, pulse >100), heart disease, heart attack, lung/respiratory disease, any pulmonary, cardiovascular, gastrointestinal, hepatic or renal functional abnormality (i.e. a medical diagnosis related to lungs, heart, stomach/intestines, liver, or kidneys), HIV, Hepatitis B, Hepatitis C, bipolar disorder, psychosis, or confirmed or suspected immunosuppression or immunodeficiency
• current (past month) alcohol or substance abuse or dependence (score of 2+ on the UNCOPE)
• consistent (e.g., 5x/week or greater) probiotic supplementation within the last month, including probiotic food products such as yogurt
• receiving antibiotics within the last month
• receiving medications that interfere with gut motility (opiates, loperamide, stool softeners)
• use of systemic antibiotics, antifungals, antivirals, or antiparasitics (intravenous, intramuscular, or oral)
• use of oral, intravenous, intramuscular, nasal or inhaled corticosteroids
• use of cytokines or cytokine inhibitors
• use of methotrexate or immunosuppressive cytotoxic agents
• receiving immunosuppressive drugs/medications or treatment including antineoplastic therapy, post-transplantation immunosuppressive therapy, and/or radiation therapy
• participation in conflicting interventional research protocol
• unstable dietary history as defined by major changes in diet during the previous month, where the subject has eliminated or significantly increased a major food group in their diet
• female who is pregnant or lactating or reports expecting to get pregnant during the course of the study
• currently involved in the criminal justice system as a prisoner or ward of the state

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Change from baseline in mean trait perceived stress as assessed by PSS-10	Baseline and the end of treatment at 46 days	Perceived stress scale-10 (PSS-10) administered via REDCap. Possible score range of 0 to 40, with 0-13 considered low stress, 14-26 moderate stress, and 27-40 high stress.
State perceived stress as assessed by adapted PSS-4 using ecological momentary assessment	Five times per day (hourly, 12-7pm, sent via text with a 15 minute response window) during the last 5 days of supplementation, days 42 to 46, when the investigators expect participants to have reached maximum benefit	Perceived stress scale-4 (PSS-4) administered via REDCap and adapted for state measurement. The investigators adapted this measure for state stress by asking participants to rate the intensity of perceived stress they were experiencing in the moment, as opposed to the frequency with which they experienced perceived stress over the past month. Possible score range of 0 to 16, with higher scores indicating higher levels of state stress.

Secondary Outcome Measures

Name	Time	Method
Change from baseline in mean trait anxiety symptoms as assessed by GAD-7	Baseline and the end of treatment at 46 days	Generalized Anxiety Disorder-7 scale (GAD-7) administered via REDCap. Possible score range of 0 to 21, with higher scores indicating higher levels of anxiety symptoms.
State anxiety symptoms as assessed with the SUDS using ecological momentary assessment	Five times per day (hourly, 12-7pm, sent via text with a 15 minute response window) during the last 5 days of supplementation, days 42 to 46, when the investigators expect participants to have reached maximum benefit	Subjective units of distress scale (SUDS) administered via REDCap. Possible score range of 0 to 100, with higher scores indicating higher levels of state anxiety.
Change from baseline in mean trait depressive symptoms as assessed by the PHQ-8	Baseline and the end of treatment at 46 days	Patient Health Questionnaire-8 (PHQ-8) administered via REDCap. Possible score range of 0 to 24, with higher scores indicating higher levels of depression.
State depressive symptoms as assessed by SUDS using ecological momentary assessment	Five times per day (hourly, 12-7pm, sent via text with a 15 minute response window) during the last 5 days of supplementation, days 42 to 46, when the investigators expect participants to have reached maximum benefit	Subjective Units of Distress Scale (SUDS) administered via REDCap. Possible score range of 0 to 100, with higher scores indicating higher levels of state depression.

Trial Locations

Locations (1)

University of Colorado Boulder, Muenzinger Psychology Building; 🇺🇸 Boulder, Colorado, United States