Ketamine is an effective rapid-acting antidepressant, but its acute dissociative effects do not predict depression response in adolescents with treatment-resistant depression. In a secondary analysis of 16 adolescents from a crossover trial, no significant associations were found between dissociative symptoms—measured by the Clinician-Administered Dissociative States Scale—and depression improvement or response one day after ketamine infusion. When receiving the control drug midazolam, higher depersonalization symptoms were linked to less improvement. These findings contrast with some adult studies and may be limited by the small sample size, which reduces the ability to detect small or medium effects.
Ketamine works as a rapid antidepressant for some but not all patients. In adolescents with treatment-resistant depression, those who had tried fewer antidepressant medications and augmentation treatments, had a shorter current depressive episode, and were currently taking a selective serotonin reuptake inhibitor (rather than a serotonin–norepinephrine reuptake inhibitor) were more likely to experience symptom improvement one and seven days after a single dose of ketamine. These findings are preliminary due to the small sample and multiple analyses, and more research is needed before using such predictors in clinical practice.