Conditions: Depression Major Depressive Disorder
Keywords: Treatment
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 21
Healthy volunteers: no

Brief summary:
Major depressive disorder (MDD) is a global medical problem with significant shortcomings in current therapy. Chief among these is the delay between initiation of pharmacologic therapy and clinical improvement in symptoms. Recently ketamine, an NDMA-receptor antagonist has been shown to rapidly and effectively reverse the symptoms of MDD. Nitrous oxide, another NMDA-receptor antagonist, may produce the same effect with a cleaner side-effect profile and perhaps without the need for intravenous access and anesthesia personnel. Therefore, we propose conducting a pilot randomized placebo controlled double-blind crossover study in which patients will receive up to 50% nitrous oxide in oxygen or up to 50% oxygen in air for a period of one hour in addition to standard medical therapy. Depression severity will be assessed by a blinded observer pre-treatment, 30 minutes and 2 hours post treatment using the Hamilton depression rating scale.

Detailed description:
We will study 20 patients with non-treatment resistant major depression and 20 patients with treatment-resistant major depression, defined as failure of at least 2 antidepressants in the current depressive episode and 3 lifetime medication failures.

Arms:
arm 1: First session: Nitrous oxide Second session: placebo arm 2: First session: Placebo Second session: Nitrous Oxide

Interventions: intervention 1: Nitrous Oxide intervention 2: Placebo
Intervention descriptions: intervention 1: Patients will receive either up to 50% nitrous oxide/50% oxygen for 1 hour or "placebo" (50% nitrogen \[inert\]/50% oxygen) in two separate sessions. Both sessions will be 1 week apart. intervention 2: 50% nitrogen \[inert\]/50% oxygen - otherwise completely identical administration and setup

Protocol document: