Pupillometry in Delayed Sleep Wake Phase Disorder

Pupillometry in DSWPD Type 1 and Type 2

Status

Recruiting

Phases

Unknown

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT06949644

Enrollment

220

Registered

2025-04-29

Start date

2025-09-01

Completion date

2029-08-31

Last updated

2026-06-08

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Delayed Sleep-Wake Phase Disorder

Brief summary

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.

Interventions

COMBINATION_PRODUCTLight and Citalopram

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

Study design

Allocation

Intervention model

SINGLE_GROUP

Primary purpose

DIAGNOSTIC

Masking

NONE

Eligibility

Sex/Gender

ALL

Age

16 Years to No maximum

Healthy volunteers

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

Design outcomes

Primary

Measure	Time frame	Description
Melatonin suppression	8 hours	Saliva melatonin samples will be collected before and after light exposure

Countries

United States

Contacts

CONTACTSabra Abbott, MD, PhD

sabra.abbott@northwestern.edu312-695-7950

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Jun 9, 2026