A Clinical Trial Evaluating Fecal Microbiota Transplantation (FMT) in Adolescents With ADHD

Starting soon · Phase 2 · Has a placebo group

Conditions studied: ADHD, ADHD - Attention Deficit Disorder With Hyperactivity, ADHD - Combined Type

In brief

The primary goals of this phase 2 clinical trial are to determine the feasibility, safety, and tolerability of oral Fecal Microbiota Transplantation (FMT) in adolescents (aged 13-17) with Attention-Deficit/Hyperactivity Disorder (ADHD).

Key facts

Study ID

NCT07756255

Run by

University of Calgary

People needed

64

Starts

2026-08-31

Expected to finish

2029-08-31

Last updated by the study team

2026-08-10

Who can join

Age: 13 and older, up to 18. Sex: any. Healthy volunteers: accepted.

You may qualify if…

• Between 13-17 years of age with consent of a legal guardian: Participants should be at least 13 years old and not older than 17 years at the day of screening (V1).
• Have a primary diagnosis of ADHD as confirmed by the Mini-International Neuropsychiatric Interview for Children and Adolescents (MINI-KID).
• Be on a stable appropriate dose of an appropriate first-line pharmacological treatment for at least 8 weeks prior to the day of screening (V1).
• a. First line pharmacotherapy treatment will be defined based on the CADDRA guidelines [63] and include the following
• Amphetamine-based psychostimulants:
• i. Mixed amphetamine salts (amphetamine and dextroamphetamine) ii. Lisdexamfetamine dimesylate
• Methylphenidate-based psychostimulants:
• i. Methylphenidate hydrochloride, Methylphenidate hydrochloride (extended release, multilayer release capsules) ii. Methylphenidate hydrochloride (extended release, OROS tablets) iii. Methylphenidate hydrochloride (controlled release, multi-layer beat capsules) iv. Methylphenidate hydrochloride (extended-release oral suspension)
• Have a score of ≥ 18 on the inattention subset (questions 1-9) and/or the hyperactivity/impulsivity subset (questions 10-18) of the SNAP-IV 26-Item Parent Rating Scale on the day of screening (V1) and the baseline visit (V2).
• Able to communicate and complete study assessments in English.
• Able to comply with all protocol procedures.
• Consenting guardian

You may not qualify if…

• Participant meets Diagnostic and Statistical Manual of Mental Disorders (DSM-5) Criteria for the following conditions according to the MINI-KID:
• Diagnosis of a Substance Use Disorder within the last 3 months prior to screening. *(Criteria should include Alcohol and Non-Alcohol substances except Cannabis)
• Moderate or severe Substance Use Disorder for Cannabis use in the last 3 months
• Currently active high suicidality. Eligibility of Participants who meet criteria for moderate suicidality is determined by clinical judgment of Principal Investigator.
• Active Anorexia Nervosa or Bulimia Nervosa in the last 3 months.
• Tic Disorders
• Psychosis
• Obsessive Compulsive Disorder
• Bipolar Disorder
• Conduct Disorder
• Participant has a score of ≥ 8 on the oppositional defiant subset of the SNAP-IV 26-Item Parent Rating Scale (questions 19-26) on the day of screening (V1).
• Intellectual or learning disability based on previous documented diagnosis or clinical judgment of Principal Investigator.
• Documented diagnosis of Pediatric Acute-onset Neuropsychiatric Syndrome (PANS) or Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections (PANDAS).
• Documented diagnosis of schizophrenia or schizoaffective disorder.
• Documented diagnosis of Autism Spectrum Disorder (ASD) or currently undergoing assessment for suspected ASD.
• Use of systemic antibiotics for medical purposes within the last 3 months prior to the day of screening (V1).
• Use of prebiotics or probiotics for medical purposes for more than 2 weeks within the last 3 months prior to the day of screening (V1).
• a) Eligibility and required washout period of participants with use of over-the-counter prebiotics or probiotics will be determined by clinical judgment of Principal Investigator.
• Use of experimental drugs in the last 3 months prior to the day of screening (V1).
• Documented clinical diagnosis of inflammatory bowel disease (IBD), Crohn's disease, ulcerative colitis, and/or celiac disease.
• Documented diagnosis of conditions causing immunosuppression and/or currently receiving immunosuppressive treatments.
• Documented clinical diagnosis of significant bleeding disorders.
• History of oropharyngeal dysphagia or other swallowing disorder, and/or self or study partner reported difficulty with taking oral capsules or pills.
• Breastfeeding, pregnant or seeking to get pregnant during the course of this study. Female participants of childbearing age should be using an acceptable method of birth control (implants, injectable, combined oral contraceptives, IUDs, barrier contraceptives, sexual abstinence, or a vasectomized partner) for the duration of their participation in the trial.
• Participants who are currently hospitalized or institutionalized.

Where it is running

• University of Calgary — Calgary, Alberta, Canada

Full record on ClinicalTrials.gov

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