Circadian Influence on Prolonged Exposure Therapy for PTSD

November 9, 2026 updated by: Edward F. Pace-Schott, Massachusetts General Hospital

Circadian Influence on Fear Extinction Resulting From Prolonged Exposure Therapy for PTSD

Proposed research will examine time-of-day effects on trauma-related fear extinction using Prolonged Exposure Therapy (PE) telemedicine for Posttraumatic Stress Disorder (PTSD) in the National Center for PTSD (NCPTSD). The primary mechanistic outcome measure will be change in psychophysiological reactivity to script-driven imagery (SDI-PR) measured, in person, at pre-treatment, after 5 PE sessions (mid-treatment), and after all 10 PE sessions (post-treatment). A secondary mechanistic outcome will be session-to-session reduction in peak subjective units of distress (SUDS) ratings to imaginal exposures. The primary clinical outcome will be change in Clinican Administered PTSD Scale (CAPS-5) severity score; a secondary clinical outcome will be session-to-session reduction in self-reported PTSD symptoms using the PTSD checklist (PCL-5). Participants meeting inclusion criteria (described below) will be randomized to either PE sessions that begin from 07:00 to a time no later than 2 hours past a participant's customary rise time, or to the last treatment session of the day beginning at 16:00 or later (26 per arm). Participants will complete daily at-home imaginal-exposure homework within the same time frame as their PE sessions are scheduled, i.e., within 2 hours of awakening for morning (AM) group and between 16:00 and 2 hours before bedtime for late afternoon (PM) group.

Study Overview

Status

Active, not recruiting

Conditions

Detailed Description

Proposed research will examine time-of-day effects on trauma-related fear extinction using PE therapy for PTSD in the National Center for PTSD (NCPTSD). The primary mechanistic outcome measure will be change in SDI-PR; a secondary mechanistic outcome will be session-to-session reduction in peak SUDS ratings to imaginal exposures. The primary clinical outcome will be change in CAPS-5 severity score; a secondary clinical outcome will be session-to-session reduction in self-reported PTSD symptoms (PCL-5). Participants meeting inclusion criteria (described below) will be randomized to either PE sessions that begin from 07:00 to a time no later than 2 hours past a participant's customary rise time, or to the last treatment session of the day beginning at 16:00 or later. Participants will complete daily at-home imaginal-exposure homework within the same time frame as their PE sessions are scheduled (i.e., within 2 hours of awakening for morning group and between 16:00 and 2 hours before bedtime for late afternoon group). The assessment schedule will be identical for all participants. Participants who meet study inclusion criteria at screening will first begin a 7-day, pre-study sleep-monitoring period with wrist actigraphy, sleep diaries and completion of a diurnal profile of salivary cortisol levels. Trauma-related fear will be assessed using the standard SDI procedures detailed below at pre-treatment, after 5 PE sessions (mid-treatment), and after all 10 PE sessions (post-treatment). The CAPS-5 will be administered at these same times. PCL-5 measurements will be obtained at each treatment session and SUDs will be obtained during all treatment sessions that include imaginal exposure (sessions 3-8). All SDI sessions will be carried out at a standardized time of day in the late-afternoon (15:00-17:00). PE treatment will be administered at a targeted rate of once per week. At each PE and assessment session, pre-session saliva samples will be obtained for cortisol measurement and normalized using the diurnal profile of cortisol obtained during the sleep-assessment week. Participants will wear the wrist actigraph and complete sleep diaries throughout PE. The diurnal cortisol profile will be repeated at the post-treatment assessment.

Study Type

Interventional

Enrollment (Actual)

29

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Massachusetts
      • Boston, Massachusetts, United States, 02130-4817
        • VA Boston Healthcare System

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 70 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  1. a diagnosis of PTSD as defined by DSM-5, with a minimum CAPS severity score of 26, a minimum PCL-5 score of 31, or a score of 2 or above on CAPS-5 Item B2 (concerning distressing dreams)
  2. interest in starting a course of PE
  3. availability for appointments at that will either begin from 07:00 to a time no longer than 2 hours past their customary rise time, or to the last treatment session of the day beginning at 16:00 or later
  4. Age range of 18-70
  5. A Morningness-Eveningness Questionnaire (MEQ) score above 25.
  6. Non-exclusionary psychotropic medications must have been stable for 3 weeks prior to Screening/Assessment with intention to remain stable throughout participation.

Exclusion Criteria:

  1. current or past history of bipolar I disorder, schizophrenic or other psychotic disorders,
  2. current organic brain disorder including moderate to severe traumatic brain injury
  3. factitious disorder or malingering
  4. pregnant or planning to become pregnant in the next four months at time of screening [if a participant does become pregnant during study procedures, the situation will be reviewed on a case-by-case basis and the participant's wishes will be considered in deciding whether the participant will continue with the study or withdraw.]
  5. current moderate or severe substance use disorder with symptoms present within the past three months
  6. diagnosed moderate to severe sleep apnea, narcolepsy, periodic limb movement, or restless legs syndrome that result in daytime sleepiness indicated by Epworth Sleepiness Scale (ESS) above 10
  7. active risk of harm to self or others
  8. evidence of clinically significant hepatic or renal disease or any other acute or unstable medical condition that might interfere with safe conduct of the study
  9. current participation in trauma-focused cognitive-behavioral therapy (e.g., Cognitive Processing Therapy, Written Exposure Therapy, Eye Movement Desensitization and Reprocessing Therapy)
  10. prior treatment with an adequate dose of PE (i.e., 8 or more sessions) to the traumatic event that would be the index trauma for treatment in the study
  11. having no memory of their traumatic event
  12. daily use of benzodiazepines
  13. methadone or suboxone maintenance therapy for past opioid addiction
  14. diagnosis of Cushing's disease, Addison's disease or use of medications that target cortisol directly such as those used to treat Cushing's disease [ketoconazole, mitotane (Lysodren), metyrapone (Metopirone), and Mifepristone (Korlym, Mifeprex)], those used to treat Addison's disease [Hydrocortisone (Cortef), prednisone or methylprednisolone], as well as cortisone or dexamethasone.
  15. persons who would habitually awaken so early that more than 2 h would elapse before a morning PE session could occur; or those who engage in habitual shiftwork or transmeridian travel

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Early morning PE

26 participants randomized to 10 weekly PE sessions in early morning (between 07:00-10:00) with homework exposures occurring occur at this same time of day.

Manualized procedures deliver ten 90-minute sessions targeted to occur weekly and administered via tele-health with the same study therapist. Session 1 will focus on psychoeducation. Session 2 involves construction of the in vivo exposure hierarchy. Sessions 3-10 focus on in-session imaginal exposures to the worst trauma memory for 45-60 min followed by 15-20 min of processing the imaginal exposure. For homework, participants will be instructed to confront situations on their hierarchy on a daily basis using recording of their imaginal exposure. Subjective Units of Distress (SUDS) ratings will be taken throughout imaginal exposure exercises.

Experimental: Late afternoon PE

26 participants randomized to 10 weekly PE sessions in late afternoon (16:00 or later) with homework exposures occurring occur at this same time of day.

Manualized procedures deliver ten 90-minute sessions targeted to occur weekly and administered via tele-health with the same study therapist. Session 1 will focus on psychoeducation. Session 2 involves construction of the in vivo exposure hierarchy. Sessions 3-10 focus on in-session imaginal exposures to the worst trauma memory for 45-60 min followed by 15-20 min of processing the imaginal exposure. For homework, participants will be instructed to confront situations on their hierarchy on a daily basis using recording of their imaginal exposure. Subjective Units of Distress (SUDS) ratings will be taken throughout imaginal exposure exercises.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Psychophysiological Reactivity to Script-driven Imagery (SDI-PR): Primary Mechanistic Outcome
Time Frame: Outcome measure 1 assessed at pre-treatment (baseline), mid-treatment (week 5), and post-treatment (week 10).

This primary mechanistic outcome, measured before, midway and after treatment is a unitary discriminant canonical variable (SDI-PR) that measures psychophysiological reactivity while listening to 2 personalized recorded scripts that describe a participant's index trauma. For each of 3 physiological measures- heart rate (HR), skin conductance (SC),and corrugator EMG (cEMG)- a response (R) score is calculated as the difference between the average level during a 30s pre-script baseline phase and the average level during a 30s imagery phase. These 3 scores are averaged across the 2 scripts and combined using standardized weights as: SDI-PR = 0.29*[HRR] +0.66*[SCR] +0.38*[cEMGR]. There is no absolute limit to how much physiological reactivity can increase in response to scripts, therefore, minimum and maximum scores do not exist. However, a proxy maximum and minimum SDI-PR was estimated using the largest and smallest SCR, HRR, and cEMGR in the study and are respectively, 35.041and -3.061.

Outcome measure 1 assessed at pre-treatment (baseline), mid-treatment (week 5), and post-treatment (week 10).
Clinician-Administered PTSD Scale for Diagnostic and Statistical Manual of Mental Disorders (DSM), Fifth Edition (CAPS-5): Primary Clinical Outcome
Time Frame: Outcome measure 2 assessed at pre-treatment (baseline), mid-treatment (week 5), and post-treatment (week 10).

This primary clinical outcome is the gold standard clinical interview for assessing PTSD severity. In CAPS-5, each of the 20 symptoms of PTSD is rated on a 5-point severity scale ranging from 0 (absent) to 4 (extreme). Total scores range from 0 to 80.

Outcome measure 2 assessed at pre-treatment (baseline), mid-treatment (week 5), and post-treatment (week 10).

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
PCL-5: PTSD Checklist for Diagnostic and Statistical Manual of Mental Disorders (DSM), Fifth Edition: Secondary Clinical Outcome
Time Frame: 10 weeks

PCL-5 contains self-ratings of how much one is bothered by each of the 20 symptoms of PTSD on a 5-point severity scale ranging from 0 (Not at all) to 4 (extremely). Outcome measure 3 is the total PTSD severity score summing all 20 items. The range of total scores for the PCL-5 is 0-80.

10 weeks
SUDS: Secondary Mechanistic Outcome
Time Frame: Starting at PE Session 3 when exposures begin

A rating scale from 0 to 100 where zero represents no distress at all and 100 represents very extreme distress, fear, or anxiety. SUDS ratings are subjective and different individuals may rate the same situation differently. An individual anchors their own ratings with personal recollection of situations considered "No Distress" to "Moderate" to "Extreme Distress".

Starting at PE Session 3 when exposures begin

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Principal Investigator: Edward F Pace-Schott, PhD, Massachusetts General Hospital
  • Principal Investigator: Suzanne L Pineles, PhD, VA Boston Health System, Boston University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

July 1, 2022

Primary Completion (Actual)

August 1, 2025

Study Completion (Estimated)

September 1, 2027

Study Registration Dates

First Submitted

June 29, 2022

First Submitted That Met QC Criteria

July 6, 2022

First Posted (Actual)

July 12, 2022

Study Record Updates

Last Update Posted (Actual)

November 12, 2026

Last Update Submitted That Met QC Criteria

November 9, 2026

Last Verified

November 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • 2021p003356
  • R21MH128619 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

We will share data every January 15 and July 15 with the NIMH Data Archives (NDA) under a NIMH Data Repositories Data Submission Agreement between NIMH and VA Boston Health System (VABHS). Data sharing is required for all NIMH-funded research projects. The NDA DSA will be approved by the VABHS IRB. Each participant will be assigned Global Unique ID (GUID) and data shared will contain no identifiable information. Shared data will include scored psychophysiological, self-report instruments, cortisol, actigraphy, and fully de-identified demographic data.

IPD Sharing Time Frame

Study data will become available following the end of the study and the publication of results.

IPD Sharing Access Criteria

Investigators can apply to the NIMH Data Archive (NDA) for permission to use these data.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Subscribe