Vitamin D as a Therapeutic Adjunct in the Stimulant Treatment of ADHD: a Proof-of-concept Tele-health Study of Stimulant-induced Improvement in Neurocognitive Functioning.

  • End date
    Aug 22, 2025
  • participants needed
  • sponsor
    Yale University
Updated on 22 March 2022
cns stimulants
Accepts healthy volunteers


The purpose of this study is to assess vitamin D as a therapeutic adjunct in the stimulant treatment of ADHD.


The specific aim of this study is to determine whether acute calcitriol (vitaminD) administration (compared to placebo) enhances the neurocognitive effects of of current stimulant medications as measured by tasks of vigilance/attention, spatial working memory, and reversal learning in individuals with (attention deficit hyperactivity disorder (ADHD) using a randomized, double-blind, placebo controlled, within-subject, two-day study design.

Primary Hypothesis: It is hypothesized that calcitriol (versus placebo) administration will enhance positive neurocognitive effects of current stimulant medications in individuals with ADHD.

Seconday (Exploratory) Hypothesis: It is hypothesized that calcitriol (versus placebo) administration alone will also enhance neurocognitive performance on tasks of attention/vigilance and/or spatial working memory.

Condition ADHD
Treatment Placebo, Calcitriol
Clinical Study IdentifierNCT04386811
SponsorYale University
Last Modified on22 March 2022


Yes No Not Sure

Inclusion Criteria

Age 18-50 years
Voluntary, written, informed consent
Physically healthy by medical and psychiatric history
DSM-5 diagnosis of ADHD
Point of Care Test results for Vitamin D equal or higher than 20 ng/ml
English speaking

Exclusion Criteria

Medical contraindication to calcitriol administration (e.g., history of hypersensitivity to calcitriol or any component of the formulation, hypercalcemia or vitamin D toxicity)
History of substance dependence (e.g., alcohol, opiates, sedative hypnotics), except for nicotine
A primary major DSM-V psychiatric disorder (e.g., schizophrenia, bipolar disorder, major depression, etc.) as determined by the Structured Clinical Interview for DSM-V (SCID), except ADHD
A history of significant medical (e.g., cardiovascular, diabetic/metabolic) or neurological (e.g., cerebrovascular accidents, seizure, traumatic brain injury) illness
Current use of psychotropic and/or potentially psychoactive prescription medications, except prescribed stimulants
Use of any prescription medications and/or over-the-counter medications, vitamins (including vitamin D) and/or herbal supplements which could have a negative clinical interaction with calcitriol or which could confound scientific results of the study, within 2 weeks prior to each test day (e.g., thiazide diuretics, Mg based antiacids, digoxin, etc,)
Levels of 25(OH)D3 below 20 ng/ml
History of kidney stones within the past 5 years
History of renal failure
History of parathyroid disorder (hyper or hypoparathyroidism)
History of osteoporosis or any pathologic fractures
Vitamin D supplementation in any form in the past 3 months
Known hypersensitivity to calcitriol
Malabsorption syndromes (i.e. Celiac sprue)
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