Subanesthetic ketamine infusions for suicide ideation in patients with bipolar and unipolar treatment refractory depression.

We evaluated the effects of repeated subanesthetic ketamine infusions on suicidal ideation (SI) in patients with major depression. 82 subjects with treatment-resistant unipolar and bipolar depression completed a two-site open-label case-series of repeated (up to four weeks) infusions of ketamine (0.5 mg/kg). Ketamine produced a significant reduction in SI as early as one hour (71.1%) and up to 1-week post-infusion (60.4%), accompanied by a reduction in overall depressive symptoms which were maintained until the 4th week. The observed anti-suicidal effect was independent of mood changes, as patients whose mood did not respond still exhibited significantly less SI than baseline.