Repeated-dose intravenous ketamine is an effective rapid-acting treatment for treatment-resistant depression. In a large-scale analysis of 1,182 participants across 51 primary studies, intravenous ketamine produced statistically significant reductions in depression symptoms compared to placebo and other control conditions, as measured by standardized clinician and self-report scales. The findings provide quantitative support for ketamine's effectiveness in treatment-resistant depression and highlight variations in treatment parameters across the literature.
Acute ketamine administration alters neural activation in multiple cortical and subcortical regions in healthy people, as shown by a meta-analysis of 18 fMRI studies with 306 participants. The analysis used multilevel kernel density analysis and ensemble thresholding to minimize bias. These findings help map the functional neuroanatomical effects of ketamine, which may inform its therapeutic use for psychiatric and neurological conditions. Future research should examine both short- and long-term neural effects in clinical populations.