An interventional study of Capnometry-Guided Respiratory Intervention and Psycho-Education in Anxiety Disorders, Trauma and Generalized Anxiety Disorder, sponsored by University of Texas at Austin. Recruiting at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-08-24.
Sponsored by University of Texas at Austin · Not applicable, Interventional, and Treatment
Purpose of the Research: The primary aim of the proposed study is to conduct a randomized parallel-group 2-arm clinical trial investigating capnometry-guided respiratory intervention (CGRI) for pathological anxiety. CGRI aims to raise end-tidal CO2 levels thereby lowering hyperventilation-induced respiratory alkalosis and its associated fear-eliciting somatic reactions. Psycho-education about anxiety and its effects (PsyEd) will serve as a credible control comparator.
Low end-tidal CO2 (ETCO2), which is an accompanying feature of hyperventilation, has been associated with a variety of anxiety disorders, including panic disorder and social phobia. More recently, researchers have examined the efficacy of capnometry-guided respiratory intervention (CGRI) as a method for increasing ETCO2 and thereby reducing hyperventilation-induced anxiety/panic symptoms. Promising preliminary efficacy studies have shown that CGRI results in decreased panic symptom frequency and severity at a rate comparable to that of cognitive therapy. A recent uncontrolled proof-of-concept study showed that CGRI led to significant reductions in trauma symptoms in a sample of patients meeting DSM-5 criteria for PTSD. However, CGRI has not been adequately evaluated in the treatment of anxiety disorders other than panic disorder with or without agoraphobia.
7,201 studies on the registry are indexed under Anxiety Disorders; 1,682 are open to participants now.
This study's planned enrollment of 180 is above the median of 80 across 6,057 interventional studies indexed under Anxiety Disorders.
Browse Anxiety Disorders studies →University of Texas at Austin is the lead sponsor of 328 studies on the registry; 79 are open to participants now.
Of its 10 completed or terminated interventional studies of FDA-regulated products, 5 (50%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Meets criteria for one or more of the following anxiety or trauma-related disorders as their "primary" mental disorder:
Exclusion Criteria:
No history of medical conditions that would contraindicate participation in fear-provocation or respiratory challenges, including:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
DSM diagnostic criteria
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
If assigned to this condition, participants will be expected to complete twice-daily 17-minute tablet-assisted breathing exercises at home for four weeks. They will also receive brief phone check-ins with their study therapist weekly to review progress and troubleshoot any problems they may be experiencing. Last, these participants will have access to a paced-breathing app that provides audio recordings to maintain specified breathing rates for up to 10 minutes.
Device: Capnometry-Guided Respiratory Intervention
If assigned to the psycho-education condition, participants will watch pre-recorded 20-minute video presentations once-weekly for four weeks. They will meet with a study staff member to watch these videos, who will be available to answer any questions. During these sessions, they will be provided information about the nature and causes of anxiety-related disorders and learn tips for coping with anxiety symptoms when they arise. At the end of their sessions with the therapist, they will receive handouts that will help reinforce what they've learned.
Behavioral: Psycho-Education
See: Arm/group descriptions
Also known as: CGRI
See: Arm/group descriptions
Also known as: PsyEd
Overall Anxiety Severity and Impairment Scale
Change from baseline in self-reported transdiagnostic anxiety symptoms (range = 0 - 20, with higher scores indexing more symptoms).
Time frame: Pre-Treatment (Week 0), Post-treatment (Week 5), 2-Month Follow-Up (Week 13)
Computerized Hamilton Anxiety Scale
Change from baseline in anxiety symptom severity. Each item is assessed both in terms of frequency and severity. Scores on these probes are summed and divided by the number of response options. Higher scores index higher severity.
Time frame: Pre-Treatment (Week 0), Post-treatment (Week 5), 2-Month Follow-Up (Week 13)
Sheehan Disability Scale
Change from baseline in overall disability (range = 0 - 30, with higher scores indexing more disability).
Time frame: Pre-Treatment (Week 0), Weekly Assessments (Weeks 1 - 4), Post-treatment (Week 5), 2-Month Follow-Up (Week 13)
PROMIS - Global Health (Mental Health Subdomain)
Change from baseline in quality of life (range = 4 - 20, with higher scores indexing higher quality of life).
Time frame: Pre-Treatment (Week 0), Weekly Assessments (Weeks 1 - 4), Post-treatment (Week 5), 2-Month Follow-Up (Week 13)
Anxiety Sensitivity Composite Measure
This composite measure will incorporate scores on the Anxiety Sensitivity Index-3 (ASI-3), Body Sensations Questionnaire (BSQ), and Texas Multi-Factor Anxiety Sensitivity Scale (TMASS). Scores on each of these individual measures will be transformed into z scores and then averaged to derive this composite index. We will measure change from baseline in anxiety sensitivity.
Time frame: Pre-Treatment (Week 0), Weekly Assessments (Weeks 1 - 4), Post-treatment (Week 5), 2-Month Follow-Up (Week 13)
Modified DIAMOND
Change from baseline in DIAMOND Diagnostic Interview + Health Anxiety Questionnaire scores.
Time frame: Pre-Treatment (Week 0), 2-Month Follow-Up (Week 13)
Plan to share: No
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