Recruiting

Citalopram with Placebo

Sponsor:

Northwestern University

Code:

NCT06949644

Conditions

Delayed Sleep-Wake Phase Disorder

Eligibility Criteria

Sex: All

Age: 16+

Healthy Volunteers: Not accepted

Interventions

Light and Citalopram

Study Details

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.

Conditions

Delayed Sleep-Wake Phase Disorder

Study ID

NCT06949644

Start date

Sep 1, 2025

Status verified date

Jun, 2026

Completion date

Aug 31, 2029

Anticipated

Primary completion date

Jul 31, 2029

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 16+

Healthy Volunteers: Not accepted

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

Study Design

Enrollment

220 participants

Anticipated

Intervention Model

Single group

Primary purpose

Diagnostic

Interventions and Outcome Measures

Arms

experimental: DSWPD

Placebo or Citalopram followed by bright light (all participants will receive both interventions in random order).

Interventions

Light and Citalopram

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

Primary outcome measure

  • Melatonin suppression [ Time Frame: 8 hours ]

Central Contacts and Locations

Central contacts

Sabra Abbott, MD, PhD

312-695-7950sabra.abbott@northwestern.edu

Locations

Northwestern University

Recruiting

Chicago, Illinois, United States, 60611

Contacts

Research Assistant

312-908-1024sleeplab@northwestern.edu

More Information

Sponsor

Northwestern University

Last update posted

Jun 8, 2026

Last verified

Jun, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by Northwestern University on 2026-06-08.