Actively Recruiting
Cannabis Effects on Sleep, Circadian Rhythms, and Light Sensitivity in Young Adults (CASCILS)
Led by University of Pittsburgh · Updated on 2026-04-06
180
Participants Needed
1
Research Sites
12 weeks
Total Duration
On this page
Sponsors
U
University of Pittsburgh
Lead Sponsor
N
National Institute on Drug Abuse (NIDA)
Collaborating Sponsor
AI-Summary
What this Trial Is About
This research aims to understand how cannabis use and stopping cannabis affect sleep, body clock rhythms, and sensitivity to light in young adults. The main questions focus on whether cannabis use and discontinuation change sleep drive and how they impact light sensitivity and the timing of the body's internal clock. The study compares regular cannabis users with non-users to explore these effects. Participants in the cannabis-using group will undergo a 1-week baseline period involving at-home monitoring with sleep diaries, actigraphy, and an EEG headband. They will then take part in a 4-week cannabis discontinuation protocol with support from a clinician and abstain from cannabis use. Both cannabis users and non-users will participate in two 2-night lab visits, one before and one after the discontinuation phase for cannabis users, to assess circadian phase and light sensitivity. Throughout the study, participants will complete various assessments including sleep tracking at home and detailed lab evaluations of circadian rhythms and retinal response. Researchers will measure homeostatic sleep drive, circadian photosensitivity, retinal responsivity, and circadian phase at different stages. The study lasts about five weeks for cannabis users and includes ongoing monitoring to understand changes related to cannabis use and abstinence.
CONDITIONS
Brief Title
Cannabis Effects on Sleep, Circadian Rhythms, and Light Sensitivity in Young Adults
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Age 18-25 years
- Physically and psychiatrically healthy as determined by study assessments
- Cannabis-Using group: Regular cannabis use defined as frequent (6-29 days/month) or daily use over the past 3 months
- Cannabis-Using group: Willingness to discontinue cannabis use for 4 weeks
- Control group: No cannabis use in the past 3 months and no daily or near-daily use in the past year
- Control group: No history of alcohol or substance use disorders
- Control group: No current sleep disorders including insomnia and delayed sleep phase disorder
- Provision of written informed consent
You will not qualify if you...
- Significant or unstable acute or chronic medical conditions such as central nervous system disorders, cardiovascular disease, liver disease, migraine, peptic ulcer disease, inflammatory bowel disease, renal failure, arthritis, diabetes, and other endocrine disorders
- History of seizure disorder
- Eye or retinal conditions like diabetic retinopathy or glaucoma
- Past or current bipolar disorder or psychotic disorders
- Daily alcohol use or regular illicit drug use other than cannabis
- Past or current substance use disorders excluding mild alcohol, cannabis, or nicotine use disorders
- Syndromal sleep disorders other than insomnia and delayed sleep phase disorder, including narcolepsy, restless legs syndrome, obstructive sleep apnea, and current night shift work
- Travel across two or more time zones in the past 60 days
- Use of benzodiazepines or non-benzodiazepine hypnotic drugs
- Individuals using medical marijuana for qualifying physical medical conditions other than mental health conditions
- Unstable or uncontrolled health conditions affecting sleep, retinal function, or well-being as determined by medical history questionnaire and screening assessments
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
Duration - 1 week
Participants complete a 1-week baseline period involving at-home sleep monitoring using sleep diaries, actigraphy, and an EEG headband.
1 week of at-home monitoring
Duration - 2 nights
Participants attend a 2-night laboratory visit for circadian phase and light sensitivity assessments.
1 visit lasting 2 nights (in-person)
Duration - 4 weeks
Cannabis-using participants undergo a 4-week cannabis abstinence protocol with clinician orientation and monitoring to assess effects on sleep and circadian rhythms.
Weekly visits for up to 4 weeks
Duration - 2 nights
Cannabis-using participants attend a second 2-night laboratory visit after the discontinuation period to reassess circadian phase and light sensitivity.
1 visit lasting 2 nights (in-person)
Trial Site Locations
Total: 1 location
1
Western Psychiatric Hospital (Thomas Detre Hall)
Pittsburgh, Pennsylvania, United States, 15213
Actively Recruiting
Research Team
B
Brant P Hasler, PhD
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NON_RANDOMIZED
Model
PARALLEL
Primary Purpose
BASIC_SCIENCE
Number of Arms
2
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