Inhaled Nitrous Oxide for Treatment-Resistant Depression: Optimizing Dosing Strategies
Status:
Completed
Trial end date:
2020-02-18
Target enrollment:
Participant gender:
Summary
Most clinical major depression responds to standard treatments (medication and
psychotherapy); however, a significant subset of depressed patients (15-20%) do not respond
to these treatments and are referred to as treatment-resistant major depression (TRMD). New
treatments for TRMD are needed, and one promising line of research are drugs known as
N-methyl-D-aspartate (NMDA) glutamate receptor antagonists. In a recent pilot study, our
group demonstrated that the NMDA antagonist nitrous oxide is effective in TRMD.
The purpose of the study aims to determine whether different concentrations of nitrous oxide
(N2O) have different antidepressant effects for adults with treatment-resistant major
depression.
All patients will receive 3 randomized, one hour nitrous oxide inhalations to placebo (0%
N2O), low dose (25% N2O), and high dose (50% N2O). Inhalation sessions will be at least 4
weeks apart. Mood will be assessed at baseline, 2 and 24 hours, and 1, 2, and 4 weeks
post-inhalation for each dose.