This study will test the efficacy of the Freespira Breathing System in adults with post traumatic stress disorder (PTSD).

The Freespira Breathing System (FBS) developed by Palo Alto Health Sciences, Inc, is a portable home device , and has been employed in breathing biofeedback in adults with panic disorder (PD). The FBS has received FDA clearance for the treatment of PD adults and is currently commercially available.

This study is a prospective, single arm, un-blinded investigation of the Freespira Breathing System in the PTSD population.

Inclusion Criteria:

Note: Office visits required. Patients must live locally in San Francisco/Silicon Valley Bay Area to participate.

Patients with a primary diagnosis of PTSD

• Additional DSM-V disorders are acceptable and will be documented.

  • Subjects over 18 years of age
  • Subjects with a Clinician's Global Impression (CGI-S) score of ≥ 4
  • Subjects with a CAPS-5 score of ≥ 30
  • If on psychotropic medication(s), on a stable dose during the course of treatment

• This can include benzodiazepine use that is prescribed on an as needed basis. • If on psychotropic medication(s), patient agreement to maintain their current stable dose from point of study entry until the 2-month post-treatment assessment.

Exclusion Criteria:

• Subject is pregnant.

• Current enrollment in another device or drug study.

• Enrollment in another drug or device study that is not at least 30 days past the final follow-up visit.

• Currently undergoing cognitive behavioral therapy, or equivalent that is focused addressing PTSD including any evidenced based therapy that focuses on PTSD, including cognitive processing therapy, EMDR, prolonged exposure therapy, Virtual reality therapy, during trial and 2 month follow up. Cognitive therapy must be discontinued 1 month prior to enrolling in this study.

• Severe suicidality, in the judgment of the interviewer and taking the CHART assessment into account

• Psychotic disorder diagnosis, including schizophrenia and schizoaffective disorder

• Presence of uncontrolled bipolar disorder as described below -

  • The subject has experienced a manic episode in the past 6 months and is not considered under control by reviewer
  • Bipolar disorder is considered the primary diagnosis for the subject, in the interviewer's opinion.

• No Alcohol, drug use disorder that requires medical treatment . If stable under medical supervision treatment for drug/alcohol use, then OK

• Cardiovascular or pulmonary disease, such as COPD.

  • Score of ≥ 10 on the COPD assessment
  • EtCO2 of ≥ 48 mmHg at first treatment visit

• Epilepsy or seizures

• Inability to understand or comply with study procedures.

• The investigator feels that for any reason the subject is not eligible to participate in the study.