Fact CheckerSign in

NCT05501678RecruitingPhase 2

Trial of Diphenhydramine for Sleep in Children With Autism

Randomized Placebo-controlled Crossover Trial of Diphenhydramine for Sleep in Children With Autism

Source: ClinicalTrials.gov · Last updated 27 Mar 2026

Brief summary (registry, in English)

The purpose of this study is to examine the effect of diphenhydramine on sleep in children and adolescents with Autism Spectrum Disorder (ASD). Diphenhydramine is an anti-histaminergic agent with strong hypnotic properties. To accomplish this, the investigators will use a randomized double-blind placebo-controlled crossover 8-week study design to examine the effect of diphenhydramine on sleep physiology as assessed by polysomnography (PSG), actigraphy, circadian rhythm, and clinical measures.

Status (registry)
Recruiting
Phase (registry)
Phase 2
Study type
Interventional
Enrollment
26 (estimated)
First submitted
12 Aug 2022
Start date
9 Aug 2023
Primary completion date
31 Dec 2027
Lead sponsor
Stanford University
Diseases
Autism
NCT number
NCT05501678

What you commit to

  • Study type: Interventional · Phase 2
  • Planned participants: 26
  • From 9 Aug 2023 to the primary completion date, 31 Dec 2027
  • 1 site in 1 country
  • Visits and tests: ask the trial team, the registry does not list them

Built from the registry fields of ClinicalTrials.gov. It describes the study, not your situation.

Who cannot take part

Copied verbatim from ClinicalTrials.gov and grouped by topic. Only the trial team decides who can take part.

Prior treatment

  • current use of any medications known to interact with diphenhydramine such as medications inhibiting CYP2D6

Other illness

  • 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)
  • 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

Other

  • Participants will be excluded if one or more of the following is met
  • 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)
  • taking anticholinergic agents (e.g., trihexyphenidyl, thioridazine).

Who the study is looking for

  • Participants will meet the following
  • 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).

Age in the registry: 8 years to 17 years · Sex: All · Does not accept healthy volunteers

Full criteria on ClinicalTrials.gov

Sites (1)

Sites in registry order. Pick your city on the disease page to sort them by distance.

SiteCityCountrySite status
Stanford University
Coordinator of this site? Confirm its status
StanfordUnited StatesRecruiting

This page is information, not medical advice. Discuss any trial with your doctor.