Evaluating CO2 Reactivity to Predict Response to Exposure Therapy for Anxiety Disorders

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This study aims to assess the predictive power of a CO2 challenge as a biomarker for determining the effectiveness of exposure-based therapy in adults with anxiety-related disorders. By evaluating CO2 reactivity in 600 participants diagnosed with conditions such as PTSD, OCD, and various anxiety disorders, the researchers hope to identify those who are likely to benefit from this therapy. The study will incorporate CO2 reactivity into a multivariable model alongside other factors to enhance treatment decision-making. This approach builds on previous research linking orexin system activity to fear extinction deficits.

Why it matters

Who can join: the full rules

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)

Where it's running

• Boston University
  Boston, Massachusetts, United States Recruiting
• The University of Texas at Austin
  Austin, Texas, United States Recruiting

Study contacts

• Principal investigator: Jasper Smits, Ph.D. — The University of Texas at Austin

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.