Back to search results

Diphenhydramine for Sleep in Children with Autism

This study is looking at how diphenhydramine (an antihistamine with sleep-inducing properties) affects sleep in children and teenagers with Autism Spectrum Disorder (ASD). Participants will receive either diphenhydramine (25mg, up to 50mg) or a matching placebo (an inactive substance) orally. Researchers will measure changes in how long it takes to fall asleep and the amount of non-rapid eye movement (NREM) sleep using special sleep tests (polysomnography and actigraphy) over 8 weeks. The study aims to enroll 26 participants aged 8 to 17 years old who have a confirmed diagnosis of ASD. The current status of the study is unclear.

Study design
This is an interventional study with a randomized, double-blind, placebo-controlled crossover design, planning to enroll 26 participants. This means some participants will receive diphenhydramine and some will receive a placebo, and neither you nor the study staff will know which you are receiving.
What's involved
Participants will be involved for 8 weeks. Sleep will be assessed using polysomnography (PSG) and/or actigraphy at the beginning of the study, at Week 4, and at Week 8.
Compensation
Not stated in the trial record.
Follow-up
Participants will be followed for 8 weeks, with sleep measurements taken at baseline, Week 4, and Week 8.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT05501678

Trial of Diphenhydramine for Sleep in Children With Autism

Recruiting
PHASE2Ages 8–17InterventionalBasic science
Stanford University
~26 participants
Updated 2026-03-27 on ClinicalTrials.gov
What's tested:DiphenhydraminePlacebo

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Change from baseline in sleep latency as measured by polysomnography (PSG) and/or actigraphy
Measured over Baseline, Week 4 and Week 8
+1 more outcome measured

Conditions

Autism
Autism Spectrum Disorder

Explore related trials

Autism Spectrum Disorder

NCT05501678

Where you'd take part

This study runs at 1 site. They're the same protocol — you choose where, and that choice sets who your contact draft is addressed to.

  • Stanford University

    Stanford, Californiastudy coordinator listed

    Recruiting

Sites open and close at different times, so the status above is per site — it can differ from the study's overall status.

Study leadership

  • Antonio Y. Hardan, MD · PRINCIPAL_INVESTIGATOR · Stanford University

Who to contact

Ryan Villacrucis
[email protected]
(650)736-1235
Email the study team

Opens a ready-to-send draft in your own email app — review before sending.

Want this trial checked against your situation?

Add a private profile and we'll compare every criterion below against your situation — and tell you which ones are met, uncertain, or excluding.

Check eligibility for this trial ~2 min · HIPAA-protected · delete anytime
Eligibility criteria

Inclusion

Outpatients between 8 and 17 years of age at the time of consent
Diagnostic and Statistical Manual, 5th edition (DSM-5) criteria for Autism Spectrum Disorder (ASD) on the basis of clinical evaluation, confirmed with the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule, 2nd Ed (ADOS-2) or the Childhood Autism Rating Scale, Second Edition (CARS-2).
Males and females
Availability of polysomnography (PSG) or actigraphy data
Sleep disturbances as assessed using Children's Sleep Habits Questionnaire (CSHQ) with a score of 41 or higher
care provider who can reliably bring participant to clinic visits, provide trustworthy ratings, and interacts with participant on a regular basis
stable medications for at least 2 weeks, with the exception of Prozac which is required to be stable for at least 4 weeks
no planned changes in psychosocial and biomedical interventions during the trial
willingness to provide additional saliva samples and participate in key study procedures (i.e., safety measurements every visit, PSG at weeks 4 and 8, and wear the actigraphy watch for 2 weeks before the beginning of trial as well as during the 8 weeks of the trial).

Exclusion

active suicidal ideation or DSM-5 diagnosis of schizophrenia, schizoaffective disorder, or psychotic disorder
active medical problems: migraine, asthma, seizure disorder, significant physical illness (e.g., anaphylaxis, serious liver, renal, or cardiac pathology)
evidence of a metabolic, or infectious etiology for the participant's autism on the basis of medical history, neurologic history, and available tests for inborn errors of metabolism and chromosomal analysis
pregnant or sexually active females not using a reliable method of contraception (urinary tests for pregnancy will be employed in this study)
individuals taking benzodiazepines, antiepileptic medications when prescribed for seizure disorder/epilepsy, melatonin and centrally-acting antihistamines
history of hypersensitivity to diphenhydramine
history of severe side effects from diphenhydramine
history of adequate trial of diphenhydramine
current use of any medications known to interact with diphenhydramine such as medications inhibiting CYP2D6
taking anticholinergic agents (e.g., trihexyphenidyl, thioridazine).

What this trial measures

  • Change from baseline in sleep latency as measured by polysomnography (PSG) and/or actigraphyBaseline, Week 4 and Week 8
  • Change from baseline in duration of non-rapid eye movement (NREM) sleep as measured by polysomnography (PSG)Baseline, Week 4 and Week 8