Replication of distinct trajectories of antidepressant response to intravenous ketamine.

Background: The goal of this study was to replicate previous findings of three distinct treatment response pathways associated with repeated intravenous (IV) ketamine infusions among patients with major depressive disorder (MDD).

Methods: We conducted growth mixture modeling to estimate latent classes of change in depression (Quick Inventory of Depressive Symptomatology-Self Report, QIDS-SR) across six treatment visits in 298 patients with MDD treated with IV ketamine in an outpatient community clinic. Mean age was 40.