Effect of Nitrous Oxide on Aggression.

This study is designed to see if inhalation of 50% nitrous oxide (N2O) also known as laughing gas, can normalize cortico-limbic circuit functioning in impulsively aggressive human subjects. If the study results are positive, it would allow further studies of this potential treatment modality for those with recurrent, problematic, impulsive aggressive behavior (Intermittent Explosive Disorder: IED). IED is a disorder in which there are frequent and sudden outbursts of anger (yelling, throwing and breaking things, hitting people) that lead to problems with other people socially or at work. It affects about 4% of the US population lifetime, and does not have any approved treatments. The study will test if N2O can normalize brain activity 24 hours after infusion, in participants with a diagnosis of IED compared with healthy, non-aggressive, controls. This is a double-blinded-randomized study with comparison between groups (controls and IED patients) and comparison for each participant between N2O and placebo (air) inhalation. Participants will receive one type of inhalation 24 hours before undergoing an fMRI. Participants will be randomized to the order in which they receive N2O or air. Participants and study personnel involved in collection of outcome measures will be blinded to the type of inhalation. The study includes up to 7 visits. Visits 1/2 include interviews and questionnaires. At visits 3 and 5, participants receive the N2O or air inhalation. At visits 4 and 6, participants undergo fMRI while completing computer tasks. Visit 7 is to assure data collection is complete.