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Cannabis Effects on Sleep and Light Sensitivity

This study is looking at how using cannabis and then stopping it affects your sleep, your body's natural sleep-wake cycle (circadian rhythms), and how sensitive you are to light. Researchers want to see if stopping cannabis for four weeks changes your need for sleep and your response to light. You might be able to join if you are between 18 and 25 years old, generally healthy, and regularly use cannabis. If you use cannabis, you must be willing to stop using it for four weeks. The study aims to enroll 180 participants, but its current status is unclear.

Study design
This interventional study will compare regular cannabis users before, during, and after stopping cannabis, and also compare them to people who don't use cannabis. The study plans to enroll 180 participants.
What's involved
You would participate in a 1-week period of at-home monitoring, followed by two 2-night lab visits. If you use cannabis, you would also participate in a 4-week cannabis discontinuation period.
Compensation
Not stated in the trial record.
Follow-up
The study measures outcomes at baseline, 1 week, and 4 weeks after discontinuation.

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NCT06743373

Cannabis Effects on Sleep, Circadian Rhythms, and Light Sensitivity in Young Adults

Recruiting
NAAges 18–25InterventionalBasic science
University of Pittsburgh
~180 participants
Updated 2026-04-06 on ClinicalTrials.gov
What's tested:Cannabis Discontinuation

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Homeostatic Sleep Drive
Measured over Baseline, 1 week
+2 more outcomes measured

Conditions

Cannabis Use
Sleep
Circadian Rhythm

Explore related trials

Cannabis misuseCircadian dysregulationSleep Disorder

Where it's being run

1 sites across 1 states
Pennsylvania1

Study leadership

  • Brant P Hasler, PhD · PRINCIPAL_INVESTIGATOR · University of Pittsburgh

Who to contact

Brant P Hasler, PhD
[email protected]
412-246-6413
Email the study team

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Eligibility criteria

Inclusion

Age 18-25 years
Physically and psychiatrically healthy, as determined by instruments described below
Cannabis-Using group only: Regular cannabis use, defined as "frequent" (6-29 days/month) or "daily" (daily) use over the past 3 months
Cannabis-Using group only: Willingness to discontinue cannabis for 4 weeks.
Control group only: No cannabis use in the past 3 months. Deny engaging in daily or near-daily cannabis use during the past year. No history of alcohol and/or substance use disorders. No current sleep disorders (including insomnia and delayed sleep phase disorder).
Provision of written informed consent

Exclusion

Past or current DSM-5 bipolar disorder or psychotic disorders. Psychiatric disorders will be evaluated using the Mini International Neuropsychiatric Interview (MINI) and the WHO-DAS 2.0, supplemented by clinical interview. We will not exclude participants for subsyndromal symptoms or disorders in these domains. We will not exclude participants for other psychiatric disorders, particularly given the high comorbidity between cannabis use disorder and major depression and anxiety disorder, as long as severity is in the moderate range or lower based on the WHO-DAS 2.0 (average score \<4).
Daily use of alcohol; regular use of illicit substances. Regular use (as defined above) of illicit substances other than cannabis over the past 3 months will be exclusionary. Substance use will be assessed using the Timeline Follow Back method, as well as a urine drug screen.
Past or current substance use disorders other than cannabis use disorder, nicotine use disorder, and mild alcohol use disorder (moderate and severe alcohol use disorder are exclusionary).
Current syndromal sleep disorders other than insomnia and delayed sleep phase disorder, including narcolepsy, restless legs syndrome, obstructive sleep apnea, and current night shift work (i.e., any work occurring between the hours of midnight and 6:00 a.m.). We will not exclude for subsyndromal symptoms or disorders in these domains. We will not exclude Cannabis-using participants for insomnia and delayed sleep phase disorder because of their conceptual overlap and high co-occurrence with sleep phenotypes of interest. Sleep disorders will be diagnosed according to criteria in the DSM-5 and the International Classification of Sleep Disorders, 3rd Edition, 2014. These disorders will be evaluated using clinical interview and the locally-developed Structured Clinical Interview for Sleep Disorders. Control participants will be excluded for any current sleep disorders, including insomnia and delayed sleep phase disorder.
Travel across 2+ time zones in the past 60 days.
Benzodiazepines and non-benzodiazepine hypnotic drugs ("Z-drugs"). Other sleep-promoting medications will be permitted, including SSRIs/SNRIs, will be permitted if on stable dose and not in the acute phase of treatment. In order to evaluate medications, participants will complete a listing of current medications, including prescription and over the counter medications, "natural" preparations, and nutritional supplements.
Individuals with a Pennsylvania Medical Marijuana Card using dispensary-obtained marijuana or other THC products for documented Qualifying Medical Conditions other than those of a mental health nature will be excluded. However, individuals who have been issued a Pennsylvania Medical Marijuana ID card for a mental health condition will not be excluded from the study.

What this trial measures

  • Homeostatic Sleep DriveBaseline, 1 week

    Rate of slow wave activity dissipation, assessed by at-home EEG headband. Compared within person (cannabis-using days vs. non using days), between groups (Cannabis-Using, Control) at Baseline, and within-group (Cannabis-Using) between Baseline and Post-discontinuation.

  • Circadian PhotosensitivityDiscontinuation, 4 weeks

    Light-Induced Melatonin Suppression. Melatonin levels on during a 60-minute light exposure will be compared to melatonin levels on a prior night under dim light conditions (when the dim light melatonin onset was assessed). The primary outcome will be % reduction in melatonin levels. Will be compared between groups (Cannabis-Using, Control) at Baseline and within-group (Cannabis-Using) between Baseline and Post-discontinuation.

  • Retinal ResponsivityEnd of discontinuation, 4 weeks

    Retinal responsivity assessed via pupillometry (specifically the Post-Illumination Pupil Response; PIPR). Will be compared between groups (Cannabis-Using, Control) at Baseline and within group (Cannabis-Using.