R-NOT for PTSD
Research type
Research Study
Full title
Developing and testing a novel memory-therapeutic treatment for PTSD: Retrieval-dependent Nitrous Oxide Therapy (R-NOT)
IRAS ID
1008993
Contact name
Georges Iskandar
Contact email
Sponsor organisation
University College London
ISRCTN Number
ISRCTN12553238
Research summary
Posttraumatic stress disorder (PTSD) is a condition that can develop after experiencing or witnessing a traumatic event. Symptoms include distressing memories, avoidance of event reminders, and heightened tension. While several effective treatments exist, they can take weeks to show results and may not work for everyone.
This project explores a new treatment targeting one of PTSD’s most troubling symptoms: intrusive memories (IM) — unwanted, distressing recollections of traumatic events. The treatment being tested is called Retrieval-dependent Nitrous Oxide Therapy (R-NOT). It involves recalling an intrusive memory followed by inhaling a 50/50 mix of nitrous oxide and oxygen (also known as “gas and air”) for an hour. This gas is believed to help weaken the emotional power of traumatic memories.
The project contains three studies that happen one after the other:
Study 1 tests a single treatment session of R-NOT in 10 people with PTSD, assessing whether it is a well-tolerated and acceptable treatment.
We will also test whether it is likely to be effective as a treatment for PTSD.
Study 2 builds on findings from Study 1, testing 3-5 sessions of R-NOT in 10 people with PTSD. This time, we want to test if R-NOT is acceptable and well-tolerated when people with PTSD receive several sessions of the treatment. During Study 2 we will also create a treatment guide.
Study 3 tests how effective R-NOT is by comparing it to two control groups in 84 people with PTSD (28 in each group). One control group recalls an IM followed by inhaling medical air (placebo) for one hour. The other control group recalls a neutral memory followed by inhaling gas and air for one hour.
The Medical Research Council is funding the project, and University College London is the sponsor. Participants will be recruited from the NHS Talking Therapies Services (NHS-TTSs) in London. If successful, R-NOT could provide a more accessible and rapid treatment option for those experiencing PTSD symptoms.REC name
London - Central Research Ethics Committee
REC reference
25/LO/0693
Date of REC Opinion
30 Oct 2025
REC opinion
Further Information Favourable Opinion