Oral Thiamine (Vitamin B1) for Depression in Children and Adolescents

NCT07793071 | Not Yet Recruiting Phase 2 FDA Drug

• 1 other identifier: 2025P003220
• Study Type: interventional
• Target: 40
• Locations: 0 countries
• Sites: N/A

Brief Summary

The goal of this study is to examine the effectiveness of thiamine in reducing depressive symptoms in children and adolescents. The investigators hypothesize that thiamine administration will alleviate depressive symptoms in children and adolescents and will have a favorable safety profile. Participants will complete a baseline virtual visit with a study clinician and parent/guardian questionnaires to assess depression symptoms, medical history, current medications, and study eligibility. Participants will complete fasting blood draws before and after the 4-week study period and, if eligible, receive study thiamine capsules by mail to take daily during the study. Participants will attend weekly virtual visits for 4 weeks to monitor depression symptoms, safety, medication adherence, side effects, and any changes in medications or treatments.

Conditions

Major Depressive Disorder (MDD); Thiamine; Vitamin B1; Thiamine Diphosphate (TDP); Pediatrics

Keywords

Major Depressive Disorder (MDD); Thiamine; Vitamin B1; Pediatrics; Thiamine Diphosphate (TDP)

Outcome Measures

Primary Outcomes (1)

• Change From Baseline in Children's Depression Rating Scale-Revised (CDRS-R) Total Score

  Change in depressive symptom severity from baseline to Week 4 as measured by the Children's Depression Rating Scale-Revised (CDRS-R). Lower scores indicate reduced depression severity and improvement in depressive symptoms over the course of thiamine treatment.

  28 days

Secondary Outcomes (1)

• Number of Participants Demonstrating Clinical Improvement on the Clinical Global Impressions-Improvement (CGI-I) Scale

  28 days

Other Outcomes (2)

• Concentration of End-of-Treatment Whole Blood Thiamine Diphosphate (TDP) and Depression Severity Measured by the Children's Depression Rating Scale-Revised (CDRS-R) Total Score at Day 28

  28 days

• Change in Blood Concentrations of C-Reactive Protein (CRP), Tumor Necrosis Factor-Alpha (TNF-α), Interleukin-6 (IL-6), and Leptin From Baseline to Day 28

  28 days

Study Arms (1)

Thiamine

EXPERIMENTAL

Participants will receive 100 mg HCl oral thiamine capsules, which will be swallowed whole.

Drug: thiamine hydrochloride 100 mg

Interventions

thiamine hydrochloride 100 mg DRUG

Participants will receive 100 mg HCl oral thiamine capsules, which will be swallowed whole.

Also known as: Vitamin B1, Thiamine Hydrochloride, Thiamine HCl

Thiamine

Eligibility Criteria

• Age: 8 Years - 17 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17)

You may qualify if:

• Male or female participants aged 8 to 17.5 years (inclusive) at the time of enrollment
• Diagnosis of major depressive disorder (MDD) according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5)
• Evidence of clinically significant symptoms of depression as indicated by a T score\> 60 on the Children's Depression Inventory 2 (CDI-2) parent form at prescreening
• Evidence of clinically significant symptoms of depression in the mild to moderate range as indicated by a score between 40 and 70 on the Children's Depression Rating Scale--Revised (CDRS-R) at screening
• Subjects and their caregivers must be English-speaking and have a level of understanding sufficient to communicate intelligently with the investigator and study coordinator, and to cooperate with all tests and examinations required by the protocol.
• Subject and their caregiver must be willing and able to comply with all study procedures.
• Each subject and his/her authorized parent/guardian must understand the nature of the study. The subject's authorized parent/guardian must sign an informed consent document, and the subject must sign an informed assent document.
• Subject must be able to swallow pills.
• Subject must have access to a computer with a camera, speaker, microphone, and internet connection.
• Subjects must be willing to refrain from treatment changes during the study protocol.

You may not qualify if:

• Recent history or active clinically significant manifestations of infectious, metabolic, hepatic, renal, hematological, pulmonary, cardiovascular, gastrointestinal, musculoskeletal, dermatological, urogenital, neurological, endocrinological or eyes, ears, nose, and throat disorders, or any other acute or chronic condition that, in the Investigator's opinion, would limit the participant's ability to complete or participate in this clinical study.
• History of sensitivity to thiamine
• Severe allergies or multiple adverse drug reactions.
• History of nutritional deficiencies other than thiamine deficiency that could interfere with the study protocol or confound results.
• DSM-V diagnosis of substance use disorder, abuse or dependence.
• Judged clinically to be at serious suicidal risk for Columbia-Suicide Severity Rating Scale (C-SSRS) score ≥4.
• Severe symptoms of depression as indicated by CDRS-R score \>70.
• Current diagnosis of bipolar disorder.
• Current diagnosis of schizophrenia.
• Current diagnosis or symptoms of psychosis.
• Previous or current diagnosis of Intellectual Disability.
• Participants who are on stable pharmacotherapy will be included as long as the medication has been stable for at least 6 weeks prior to screening and will continue without change for the duration of the study. Participants on pharmacotherapy that has not been stable for at least 6 weeks will be excluded.
• Participants who are in stable psychotherapy will be included as long as they have started psychotherapy at least 3 months prior to screening and will continue therapy without change for the duration of the study. Participants receiving psychotherapy that has not been stable for at least 6 weeks will be excluded.
• Concomitant treatment or treatment within the last month with neuroleptics, antipsychotics, anticonvulsants, sedatives or hypnotics.
• More than two antidepressant treatment failures at an adequate dose and duration (at least 6 weeks) in the current major depressive episode.

Sponsors & Collaborators

• Massachusetts General Hospital: lead

MeSH Terms

Conditions

Depressive Disorder, Major

Interventions

thiamine hydrochloride; Thiamine

Condition Hierarchy (Ancestors)

Depressive Disorder; Mood Disorders; Mental Disorders

Intervention Hierarchy (Ancestors)

Thiazoles; Sulfur Compounds; Organic Chemicals; Azoles; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Pyrimidines

Central Study Contacts

Clotilde Guidetti, MD

CONTACT

617-634-4475; cguidetti@mgh.harvard.edu

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: This will be a 28-day, open-label, Phase 2a pilot trial to evaluate the efficacy and safety of 100 mg of daily oral thiamine in the treatment of depression in children and adolescents.

Study Record Dates

• First Submitted: August 18, 2026
• First Posted: August 28, 2026
• Study Start (Estimated): October 1, 2026
• Primary Completion (Estimated): January 1, 2029
• Study Completion (Estimated): January 1, 2029
• Last Updated: August 28, 2026

Record last verified: 2026-08

Data Sharing

• IPD Sharing: Will not share