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NCT Number: NCT06949644

Pupillometry in Delayed Sleep Wake Phase Disorder

The goal of this observational study is to characterize the pupil light response in patients with delayed sleep-wake phase disorder. A subset of participants will take part in a clinical trial to determine if increasing serotonin can alter the circadian response to light. The main questions it aims to answer is:

Are there differences in the light response in patients with delayed sleep-wake phase disorder? Does citalopram increase melatonin suppression in patients with delayed sleep-wake phase disorder?

Participants will complete activity and melatonin testing at home to determine their circadian timing. This will be followed by an eye test looking at the pupil response to different light stimuli. A subset of participants will complete two inpatient admissions where melatonin levels will be sampled and they will be exposed to a bright light. During one round of testing they will receive a placebo and in the other round of testing they will take a single dose of citalopram, a selective serotonin reuptake inhibitor.

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Key information

Conditions

Delayed Sleep-Wake Phase Disorder Chronobiology Disorders Dyssomnias Mental Disorders Nervous System Diseases Occupational Diseases Sleep Disorders, Circadian Rhythm Sleep Wake Disorders

Age range

16 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Northwestern University

Chicago, Illinois, 60611, United States

Location status: Recruiting

Location contact

Research Assistant

CONTACT

[email protected]

312-908-1024

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Delayed sleep-wake phase disorder

Exclusion criteria

  • Use of medications known to alter pupil diameter
  • History of eye disease or eye surgery
  • Unstable medical or psychiatric condition
  • Shift work or self imposed irregular sleep schedules
  • Caffeine consumption >400mg/day

Treatment and study plan

Light and Citalopram

Combination Product

Participants will receive placebo or citalopram, followed by bright light exposure

Primary outcomes

  1. Melatonin suppression

    Time frame: 8 hours

    Saliva melatonin samples will be collected before and after light exposure

Study contacts

Contact information is provided by the study sponsor or research team.

Sabra Abbott, MD, PhD

CONTACT

[email protected]

312-695-7950

Sponsors and collaborators

Lead sponsor

Northwestern University

Other

Collaborators

  • National Heart, Lung, and Blood Institute (NHLBI)

Registry information

Official study title

Pupillometry in DSWPD Type 1 and Type 2

Important dates

Study start
2025
Primary completion
2029
Study completion
2029
First posted
Apr 29, 2025
Registry last updated
Jun 8, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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