A Phase 3 interventional study of MEOPA (Nitrous Oxide/Oxygen Premix) and Medical Air in Oxygen in PTSD - Post Traumatic Stress Disorder, sponsored by University Hospital, Tours. Not yet recruiting at 3 sites in France. Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-11-10.
Sponsored by University Hospital, Tours · Phase 3, Interventional, and Treatment
The goal of this double-blind randomized controlled superiority clinical trial is to evaluate whether medical nitrous oxide/oxygen premix (MEOPA), combined with exposure to a personalized traumatic script, can improve symptoms of posttraumatic stress disorder (PTSD) in adults with treatment-resistant PTSD related to interpersonal violence.
The main questions it aims to answer are:
Researchers will compare participants receiving MEOPA plus traumatic script exposure with participants receiving medical air plus traumatic script exposure to determine whether MEOPA enhances the therapeutic effects of trauma-focused re-exposure.
Participants will:
200 studies on the registry are indexed under Combat Disorders; 90 are open to participants now.
This study's planned enrollment of 96 is above the median of 72 across 167 interventional studies indexed under Combat Disorders.
Browse Combat Disorders studies →University Hospital, Tours is the lead sponsor of 307 studies on the registry; 79 are open to participants now.
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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.
Exclusion Criteria:
Psychotic, bipolar, dissociative identity, or eating disorders.
* suicidal risque with C-SSR score ≥4
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.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
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.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants receive inhaled medical nitrous oxide/oxygen premix (MEOPA) combined with exposure to a personalized traumatic script. Four treatment sessions are administered at weekly intervals. During each session, participants undergo 45 minutes of inhalation following the reading of their personalized traumatic script.
Drug: MEOPA (Nitrous Oxide/Oxygen Premix) · Behavioral: Personalized Traumatic Script Exposure
Participants receive inhaled medical air combined with exposure to a personalized traumatic script. Four treatment sessions are administered at weekly intervals. During each session, participants undergo 45 minutes of inhalation following the reading of their personalized traumatic script.
Other: Medical Air in Oxygen · Behavioral: Personalized Traumatic Script Exposure
Inhalation of a premixed medicinal gas containing nitrous oxide and oxygen (MEOPA), administered via face mask during four weekly sessions in combination with exposure to a personalized traumatic script.
Inhalation of medical air administered via face mask during four weekly sessions in combination with exposure to a personalized traumatic script.
Exposure to an individualized traumatic script written by the participant and read during each treatment session as part of a trauma-focused memory re-exposure procedure. The intervention is administered in combination with either MEOPA or medical air.
Change in PTSD symptom severity measured using the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) until 3 months
The primary endpoint is the change in PTSD symptom severity, as assessed by the CAPS-5 scale, between baseline (Day 0, prior to treatment initiation) and the 3-month follow-up assessment.
Time frame: Day 0 and 3 months
Change in PTSD symptom severity using the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) until 9 months
The secondary endpoint is the change in PTSD symptom severity, as assessed by the CAPS-5 scale, between baseline (Day 0, prior to treatment initiation), 3 months and the 9-month follow-up assessment.
Time frame: Day 0, 3 months and 9 months
Change in depression severity using the Patient Health Questionnaire-9 (PHQ-9) until 9 months
The secondary endpoint is the change in depression severity, as assessed by the PHQ-9 scale, between baseline (Day 0, prior to treatment initiation), 3 months, 6 months and the 9-month follow-up assessment.
Time frame: Day 0, 3 months, 6 months and 9 months
Change in anxiety symptoms using the State-Trait Anxiety Inventory (STAI) until 9 months
The secondary endpoint is the change in anxiety symptom severity, as assessed by the STAI scale, between baseline (Day 0, prior to treatment initiation), 3 months, 6 months and the 9-month follow-up assessment.
Time frame: Day 0, 3 months, 6 months and 9 months
Change in PTSD symptom severity using the PTSD Checklist for DSM-5 (PCL-5) until 9 months
The secondary endpoint is the change in PTSD symptom severity, as assessed by the PCL-5 scale, between baseline (Day 0, prior to treatment initiation), 3 months, 6 months and the 9-month follow-up assessment.
Time frame: Day 0, 3 months, 6 months and 9 months
Change in dissociative symptoms using the Dissociative Experience Scale (DES-28) until 9 months
The secondary endpoint is the change in dissociative symptoms, as assessed by the DES-28 scale, between baseline (Day 0, prior to treatment initiation), 3 months, 6 months and the 9-month follow-up assessment.
Time frame: Day 0, 3 months, 6 months and 9 months
Change in functional impairment using the Functioning Assessment Short Test (FAST) until 9 months
The secondary endpoint is the change in fuctional impairment, as assessed by the FAST scale, between baseline (Day 0, prior to treatment initiation), 3 months, 6 months and the 9-month follow-up assessment.
Time frame: Day 0, 3 months, 6 months and 9 months
Plan to share: No
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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