ADHD, Gut Problems and Synbiotic

Gut-Brain Study: ADHD, Gastrointestinal Problems and Synbiotic Cap

The scope of this study is to evaluate the impact of a synbiotic product (a combination of probiotic bacteria and prebiotics) on symptoms reported by participants with ADHD. The main focus is to study the efficacy of the synbiotic product as compared to a placebo in improving emotion regulation and gut-health associated symptoms in adults with ADHD.

Study Overview

• Status: Not yet recruiting
• Conditions: ADHD; Gastrointestinal; Emotion Regulation Abilities
• Intervention / Treatment: Dietary supplement: Synbiotic Cap Gut-Brain; Other: Placebo

• Study Type: Interventional
• Enrollment (Estimated): 174
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Ludvig Ekelund; Phone Number: +46 8 6601660; Email: forskning@supersynbiotics.se

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• ADHD-diagnosis
• Self-described gastrointestinal problems
• Has not previously consumed Synbiotics
• Be prepared to avoid supplements with lactic acid bacteria, calcium and vitamin B6, B9, and B12, starting from washout

Exclusion Criteria:

• Has consumed antibiotics within the previous 6 weeks
• Has a serious disease that requires treatment and/or leads to a weakened immune system

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Synbiotic Cap Gut-Brain; Capsules containing the synbiotic product being evaluated. The product consists of a combination of probiotic bacteria (at a total dose of 15 x 10^9 CFU/2 capsule), dietary fibers (120 mg), calcium and vitamin B. The participants will be instructed to consume 2 capsules once every day, during a period of 12 weeks.	Dietary supplement: Synbiotic Cap Gut-Brain; Capsules (2 capsules to be ingested once daily during 12 weeks)
Placebo Comparator: Placebo; Capsules containing placebo consisting of maltodextrin. The capsules look, smell and taste the same as the capsules for the experimental product. The participants will be instructed to consume 2 capsules once every day, during a period of 12 weeks.	Other: Placebo; Capsules (2 capsules to be ingested once daily during 12 weeks)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline in the total score of Difficulties Regulation Scale 16 (DERS-16) after 12 weeks of intervention.	All subscales are included in the total score of DERS-16 (Clarity, Goals, Impulse, Strategies and Nonacceptance)	Change from baseline to 12 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline in total score for gastrointestinal symptoms (based on a questionnaire) after 12 weeks of intervention.	The questionnaire consists of a 5-point scale to evaluate the frequency of symptoms such as flatulence, bloating, loose/hard stools, gut pain, feeling sick.	Change from baseline to 12 weeks
Change from baseline in total score of ASRS v1.1 after 12 weeks of intervention	The adult ADHD self-report scale consists of 18 items. Change from baseline in the total score for these items will be measured.	Change from baseline to 12 weeks
Change from baseline in the DERS-16 subscale scores after 12 weeks of intervention.	The score for each of the DERS-16 subscales (Clarity, Goals, Impulse, Strategies and Nonacceptance) will be analyzed separately	Change from baseline after 12 weeks.
Change from baseline in the frequency of individual gastrointestinal symptoms after 12 weeks of intervention.	The individual gastrointestinal symptoms include flatulence, bloating, loose/hard stools, gut pain, feeling sick.	Change from baseline to 12 weeks
Change from baseline in the score of individual ASRS v1.1 items after 12 weeks of intervention.	The 18 ASRS items will be assessed separately.	Change from baseline to 12 weeks.

Collaborators and Investigators

• Sponsor: Super Synbiotics AB

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): October 31, 2027
• Study Completion (Estimated): December 1, 2027

Study Registration Dates

• First Submitted: July 16, 2026
• First Submitted That Met QC Criteria: July 16, 2026
• First Posted (Actual): July 21, 2026

Study Record Updates

• Last Update Posted (Actual): July 21, 2026
• Last Update Submitted That Met QC Criteria: July 16, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: ADHD; probiotics; emotion regulation; gut-brain axis; gastrointestinal health; synbiotics
• Additional Relevant MeSH Terms: Mental Disorders; Neurodevelopmental Disorders; Attention Deficit and Disruptive Behavior Disorders; Behavior; Social Behavior; Self-Control; Attention Deficit Disorder with Hyperactivity; Emotional Regulation
• Other Study ID Numbers: Gut-Brain Study

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No