Major Depressive Disorder (MDD)Phase 2B1PedNCT07793071
Oral Thiamine (Vitamin B1) for Depression in Children and Adolescents
A Phase 2 study testing thiamine hydrochloride 100 mg in people with Major Depressive Disorder (MDD) and Thiamine, run by Massachusetts General Hospital.
Trial 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. Read more about this study
- Who is it for?
- Ages 8 to 17 years
- Conditions the study is for
- Major Depressive Disorder (MDD), Thiamine, Vitamin B1
- What is being tested?
- thiamine hydrochloride 100 mg
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- No sites listed yet
- Study dates
- 1 Oct 2026to 1 Jan 2029
- Phase
- Phase 2
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 8 to 17 years
- All sexes
- No healthy volunteers
- Child
Who may be able to join
- 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.
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- 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.
Who cannot join
- 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.
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- 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.
- Having started psychotherapy (including cognitive behavioral therapy [CBT]) less than 3 months prior to Screening
- Pregnancy: Female participants who are pregnant or breastfeeding will be excluded to avoid risks to the child and ensure safety in the use of thiamine.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: An Open-Label Clinical Trial Conducted Via Telepsychiatry of Oral Thiamine for the Treatment of Depression In Youth
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.
Read more
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.
Read the detailed description
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. Subjects will include pediatric patients 8-17 years of age with elevated depressive symptoms. The investigators plan to enroll 40 subjects to account for an expected dropout rate, with the goal of retaining 30 participants for analysis.
The main outcome measures will be improvement in depressive symptoms as measured by the Children Depression Rating Scale-Revised (CDRS-R). Overall clinical functioning will be assessed using the Clinical Global Impression of Severity (CGI-S) and Improvement (CGI-I) scales. The Children's Depression Inventory-2 Parent Form (CDI-2) will also be included as a secondary outcome measure.
Thiamine status will be assessed by measuring thiamine diphosphate (TDP) concentrations in whole blood samples (3 mL), collected in EDTA tubes (lavender top) at two time points: at baseline and at the end of study (Day 28).
In addition to measuring thiamine diphosphate (TDP) concentrations, the investigators will also assess a panel of inflammatory and metabolic biomarkers at baseline and at the end of study (Day 28). These biomarkers include C-reactive protein (CRP), tumor-necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and leptin.
Biomarker testing allows exploration of potential thiamine mechanisms of action.
The investigators plan to treat subjects with the following doses:
Thiamine hydrochloride (HCL): 100 mg daily
At each visit, measures of safety and efficacy will be obtained using rating scales.
- Conditions
- Major Depressive Disorder (MDD), Thiamine, Vitamin B1, Thiamine Diphosphate (TDP), Pediatrics
- Being tested
- thiamine hydrochloride 100 mg
- Keywords
- Major Depressive Disorder (MDD), Thiamine, Vitamin B1, Pediatrics, Thiamine Diphosphate (TDP)
- Medical subject headings
- Depressive Disorder, Major
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
thiamine hydrochloride 100 mgDrug
Also called Vitamin B1, Thiamine Hydrochloride, Thiamine HCl
Participants will receive 100 mg HCl oral thiamine capsules, which will be swallowed whole.
| Study group | Role | What they receive |
|---|---|---|
| Thiamine | Experimental | Participants will receive 100 mg HCl oral thiamine capsules, which will be swallowed whole. Receives: Drug: thiamine hydrochloride 100 mg |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 28 days
Secondary outcomes (1)
Number of Participants Demonstrating Clinical Improvement on the Clinical Global Impressions-Improvement (CGI-I) Scale
Number of participants demonstrating clinical improvement on the Clinical Global Impressions-Improvement (CGI-I) Scale at Week 4. The proportion of participants meeting the predefined improvement threshold will be reported along with the corresponding 95% confidence interval.
Measured: 28 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Aug 2026
- Study start1 Oct 2026 (estimated)
- Primary completion1 Jan 2029 (estimated)
- Study completion1 Jan 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Major Depressive Disorder (MDD)Studies of the same condition, open and under way.
- More trials run by Massachusetts General HospitalThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- 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.
- Masking
- None (open label)
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Massachusetts General Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Clotilde Guidetti, Massachusetts General Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07793071
- Sponsor's protocol ID
- 2025P003220
- Acronym
- B1Ped
- Status last verified
- Aug 2026
- First submitted
- 18 Aug 2026
- Last updated
- 28 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No