Clinical Data

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Clinical Evidence in Support of Freespira

Research has shown that many people with panic attacks and other symptoms of panic disorder (PD) breathe differently than other people; all the time1,2,3 as indicated by their respiration rates and exhaled CO2 levels (together, their breathing pattern). Based on a randomized controlled trial, a protocol was developed to teach/train patients with panic attacks and panic disorder how to adjust their breathing patterns and exhaled CO2 levels. This protocol was then utilized in clinical trials at Stanford University and was successful in reducing panic symptoms, including panic attacks, with 68% of patients panic attack free at 12 months post treatment.4 The Freespira device and protocol is based on this work and is now FDA-cleared and commercially available for treating panic attacks and other symptoms of panic disorder.


A Freespira multi-center clinical trial was conducted to validate the results from the initial academic Stanford University trial.  Principal Investigator, David Tolin, PhD (Director of Anxiety Disorders Center, The Institute of Living and Adjunct Professor of Psychiatry at Yale University School of Medicine) and 3 additional outpatient anxiety treatment centers in the United States (11 therapists), trained panic disorder patients to use Freespira at-home, twice daily for four consecutive weeks.


The participants had four weekly visits and at the completion of the one month treatment, they were followed up at 2- , 6- and 12-months. 

Immediately post-treatment:

  • 71% of treated patients were free of panic attacks
  • 85% had a symptom reduction

At 12-months post Freespira treatment:

  • 79% of treated patients were free of panic attacks
  • 82% reported symptom reduction

The Freespira Multi-Center Clinical Trial was recently published in the peer reviewed Journal of Applied Psychophysiology and Biofeedback.  You can view the paper here.


1Bass, C, Lelliott, P, Marks, I (1989). Fear talk versus voluntary hyperventilation in agoraphobics and normal: A controlled study. Psychological Medicine, 19(3), 669-676

2Ley, R (1985) Blood, breath and fears: A hyperventilation theory of panic attacks and agoraphobia. Clinical Psychology Review, 5(4), 271-285.

3Papp, LA, Martinez, JM, Klein, DF et al. (1997). Respiratory psychophysiology of panic disorder: Three respiratory challenges in 98 subjects. American Journal of Psychiatry, 154, 1557-1565.

4Meuret AE, et al. Feedback of end-tidal pCO2 as a therapeutic approach for panic disorder. Journal of Psychiatric Research 2008;42;560-8.

5Meuret AE, et al. Changes in respiration mediate changes in fear of bodily sensations in panic disorder. Journal of Psychiatric Research 2009;43;634-41.

6Tolin, D.F., McGrath, P.B., Hale, L.R. et al. A Multisite Benchmarking Trial of Capnometry Guided Respiratory Intervention for Panic Disorder in Naturalistic Treatment Settings. Appl Psychophysiol Biofeedback, March 2017, Volume 42, Issue 1, pp 51–58.