Recently performed and published studies have shown that a very low dose of ketamine infused over one hour has had dramatic positive effects on clinical depression, especially towards suicidal feelings and in cases that don’t respond to standard treatment. The results show a pretty immediate resolution of depression, immediately or in a few hours. The relief from a single infusion can last for as little as a few hours to as much as a few weeks. In general, most patients typically experience one to two weeks of relief.