Exploring Nitrous Oxide Effects for Post Traumatic Stress Disorder (PTSD)
Phase: PHASE2
Conditions: Post Traumatic Stress Disorder
Sponsor: Stanford University

June 26, 2020  
Protocol Title: Exploring Nitrous Oxide Effects for Posttraumatic Stress Disorder (PTSD) 
NCT03375294 
 
Study Protocol/Method  
Three veteran outpatients (ages 31, 43, and 46 years) who met PTSD criteria of at least moderate 
symptom severity (Clinician-Administered PTSD Scale for DSM-5 [CAPS-5] score ≥ 40) were recruited 
from the Veterans Affairs Palo Alto Health Care System between April 2018 and July 2019. Individuals 
were excluded if they had comorbid psychiatric or medical conditions that increased the risk of 
participation. All participants completed a single 1-hour subanesthetic inhalation of 50% nitrous oxide 
and 50% oxygen administered by an anesthesiologist via face mask and standard semi-closed anesthetic 
circuit with a total gas flow rate of 4–8 L/min. A trained independent evaluator rated PTSD symptoms 
using CAPS-5 at baseline and 1 week after drug administration.  
Statistical Analysis Plan  
Response was defined a priori as a CAPS-5 score reduction of 12 points at 7 days.