Respiratory Training in the Treatment of Transdiagnostic Pathological Anxiety

Respiratory Training in the Treatment of Transdiagnostic Pathological Anxiety: A Randomized Clinical Trial

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.

Inclusion Criteria:

1. Clinically elevated anxiety as indicated by an eight or higher on the Overall Anxiety Severity and Impairment Scale (OASIS).

2. Meets DSM-5 criteria for one or more of the following anxiety or trauma-related disorders as their "primary" mental disorder:

   • Generalized Anxiety Disorder
   • Panic Disorder
   • Health Anxiety
   • Agoraphobia
   • Social Anxiety Disorder
   • Posttraumatic Stress Disorder
   • Acute Stress Disorder
   • Adjustment Disorder with primary anxious mood
   • Anxiety disorder not otherwise specified

3. No current use of psychotropic medications or stable on current medications for at least 6 weeks

4. Age 18+.

5. Able to arrange transportation to our laboratory for study appointments.

6. Fluent in English.

Exclusion Criteria:

1. No history of medical conditions that would contraindicate participation in fear-provocation or respiratory challenges, including:

   • Cardiovascular or respiratory disorders
   • High blood pressure
   • Epilepsy
   • Strokes
   • Seizures
   • History of fainting
   • Pregnant or lactating

2. Not currently receiving other psychological treatment for anxiety.

3. No history of a suicide attempt within the past 6 months.

4. No history of psychosis within the past 6 months.

5. No history of moderate to severe alcohol or substance use disorder (with the exception of nicotine) within the past 3 months.

6. Does not endorse COVID-19 symptoms during the screening phase.