CO2 Reactivity as a Biomarker of Non-Response to Exposure-Based Therapy

NCT ID: NCT05467683

Last Updated: 2026-01-14

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Clinical Phase

NA

Total Enrollment

600 participants

Study Classification

INTERVENTIONAL

Study Start Date

2022-11-02

Study Completion Date

2027-04-01

Brief Summary

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Anxiety-, obsessive-compulsive and trauma- and stressor-related disorders reflect a significant public health problem. This study is designed to evaluate the predictive power of a novel biomarker based on a CO2 challenge, thus addressing the central question "can this easy-to-administer assay aid clinicians in deciding whether or not to initiate exposure-based therapy?"

Detailed Description

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Exposure-based therapy is an effective first-line treatment for anxiety-, obsessive-compulsive and trauma- and stressor-related disorders. However, many patients fail to respond or achieve remission with exposure-based therapy, resulting in prolonged suffering, loss of productivity, and poorly used resources. Making available a biomarker assay that can aid clinicians and patients in treatment selection has the potential to have considerable public health impact.

Basic research on fear extinction--a core mechanism of action of exposure-based therapy--may inform the development of a biomarker for the selection (yes/no) of exposure-based therapy. Growing evidence links orexin system activity to deficits in fear extinction. Our group has demonstrated that reactivity to CO2 challenge, which is a safe, affordable and easy-to-implement procedure, can serve as a proxy for orexin system activity and predicts fear extinction deficits in rodents.

Building upon this basic research, the goal for the proposed study is to validate CO2 reactivity as a biomarker of exposure-based therapy non-response. To this end, we will assess CO2 reactivity in 600 adults meeting for one or more fear- or anxiety-related disorders prior to providing open, state-of-the art, transdiagnostic exposure-based therapy. By incorporating CO2 reactivity into a multivariable model predicting treatment non-response that also includes reactivity to hyperventilation as well as a number of related and theoretically-relevant prognostic variables, we will establish the mechanistic specificity and the additive predictive value of the putative biomarker. By developing models independently within two study sites and predicting the other site's data, we will validate that the results are likely to generalize to future clinical samples.

The proposed study represents a necessary stage in translating basic research to strategies for treatment selection. The investigation addresses an important public health issue by testing an accessible clinical assessment strategy--informed by basic research--that may lead to a more effective treatment selection (personalized medicine) for patients with anxiety- and fear-related disorders and enhance our understanding of the mechanisms governing exposure-based therapy.

Conditions

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Obsessive-Compulsive Disorder Post Traumatic Stress Disorder Generalized Anxiety Disorder Social Anxiety Disorder Panic Disorder

Study Design

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Allocation Method

NA

Intervention Model

SINGLE_GROUP

Primary Study Purpose

TREATMENT

Blinding Strategy

NONE

Study Groups

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Open Exposure-Based Therapy (EBT)

All participants will receive a well-established psychological treatment.

Group Type OTHER

Exposure-Based Therapy

Intervention Type BEHAVIORAL

Treatment will consist of 12 one-hour sessions, delivered over the course of 12 weeks. EBT will be delivered by trained and experienced license-eligible clinicians. The study clinician will develop a personalized assessment and treatment plan for each patient. Consistent with contemporary models of EBT, exposure practice aims to help patients reestablish a sense of safety around feared cues. Hence, exposure exercises are planned to ensure violation of threat expectancies. That is, exposure practice is deemed appropriate and effective if it allows the patient to learn that what they feared would happen does not happen. Practice will occur across relevant contexts both within and outside the session (i.e., homework) and clinicians will guide patients in processing practice to facilitate the consolidation of safety learning. To achieve these ends, study clinicians will use the manual "Personalized Exposure Therapy: A Person-Centered Transdiagnostic Approach".

Interventions

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Exposure-Based Therapy

Treatment will consist of 12 one-hour sessions, delivered over the course of 12 weeks. EBT will be delivered by trained and experienced license-eligible clinicians. The study clinician will develop a personalized assessment and treatment plan for each patient. Consistent with contemporary models of EBT, exposure practice aims to help patients reestablish a sense of safety around feared cues. Hence, exposure exercises are planned to ensure violation of threat expectancies. That is, exposure practice is deemed appropriate and effective if it allows the patient to learn that what they feared would happen does not happen. Practice will occur across relevant contexts both within and outside the session (i.e., homework) and clinicians will guide patients in processing practice to facilitate the consolidation of safety learning. To achieve these ends, study clinicians will use the manual "Personalized Exposure Therapy: A Person-Centered Transdiagnostic Approach".

Intervention Type BEHAVIORAL

Eligibility Criteria

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Inclusion Criteria

* A primary DSM-5 diagnosis of panic disorder (with or without an agoraphobia diagnosis), social anxiety disorder, generalized anxiety disorder, obsessive-compulsive disorder, or post-traumatic stress disorder as assessed by the Structured Clinical Interview for the DSM-5 (SCID-5)
* A score of 8 or greater on the Overall Anxiety Severity and Impairment Scale (OASIS)
* Ages 18 to 70
* Willingness and ability to provide informed consent and comply with the requirements of the study protocol.
* Proficiency in English (because assessment instruments have only been validated in English)

Exclusion Criteria

* A lifetime history of bipolar or psychotic disorders, substance use disorders (other than nicotine) or eating disorder in the past 6 months; serious cognitive impairment.
* Active suicidal ideation with at least some intent to act with or without specific plan (a rating of 4 for suicidal ideation on the Columbia-Suicide Severity Rating Scale) or suicidal behaviors (actual attempt, interrupted attempt, aborted or self-interrupted attempt, or preparatory acts or behavior) within the past 6 months.
* Medical conditions contraindicating CO2 inhalation or hyperventilation challenge (e.g., cardiac arrhythmia, cardiac failure, asthma, lung fibrosis, high blood pressure, epilepsy, or stroke).
* Pregnancy or lactation
* Ongoing psychotherapy directed toward the primary disorder.
* Pharmacological treatment started within 8 weeks prior to the screen (patients "stable" on their medication regimen will be included and their medication status will be included as a variable in the model)
Minimum Eligible Age

18 Years

Maximum Eligible Age

70 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Boston University

OTHER

Sponsor Role collaborator

National Institute of Mental Health (NIMH)

NIH

Sponsor Role collaborator

University of Texas at Austin

OTHER

Sponsor Role lead

Responsible Party

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Jasper A. Smits

Professor of Psychology

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Jasper Smits, Ph.D.

Role: PRINCIPAL_INVESTIGATOR

The University of Texas at Austin

Michael Otto, Ph.D.

Role: PRINCIPAL_INVESTIGATOR

Boston University

Locations

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Boston University

Boston, Massachusetts, United States

Site Status RECRUITING

The University of Texas at Austin

Austin, Texas, United States

Site Status RECRUITING

Countries

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United States

Facility Contacts

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Michael Otto, Ph.D.

Role: primary

617-353-9610

Jasper Smits, Ph.D.

Role: primary

512-475-8095

References

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Smits JAJ, Monfils MH, Otto MW, Telch MJ, Shumake J, Feinstein JS, Khalsa SS, Cobb AR, Parsons EM, Long LJ, McSpadden B, Johnson D, Greenberg A; Exposure Therapy Consortium. CO2 reactivity as a biomarker of exposure-based therapy non-response: study protocol. BMC Psychiatry. 2022 Dec 27;22(1):831. doi: 10.1186/s12888-022-04478-x.

Reference Type DERIVED
PMID: 36575425 (View on PubMed)

Other Identifiers

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1R01MH125951-01A1

Identifier Type: NIH

Identifier Source: secondary_id

View Link

1R01MH125949-01A1

Identifier Type: NIH

Identifier Source: secondary_id

View Link

STUDY00001631

Identifier Type: -

Identifier Source: org_study_id

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