Novel Biomarkers for Suicidality and Treatment Outcome

The purpose of this study is to examine whether neural-derived exosomal miRNAs are differentially expressed that are specific to suicidal ideation or behavior, and which by affecting specific miRNA targets and pathways, are associated with suicidal behavior and response to ketamine. The following groups of subjects will be examined: 1) major depressive disorder (MDD) with a recent suicide attempt (in past 2 weeks), 2) MDD with serious ideation (in the past 7 days) without recent suicide attempt (in the past 6 months), 3) MDD without clinically significant suicidal ideation (in the past 7 days) or recent suicide attempt (in the past 6 months), and 4) healthy controls. Both suicidal and non-suicidal MDD will be given ketamine (0.5 mg/kg, IV) and blood will be drawn at predose, 30 min, 180 min, 24 hours, and 14 days post-infusion to measure changes in miRNAs.