Department of Adult Psychiatry and Psychotherapy, University Hospital of Psychiatry Zurich, University of Zurich, Lenggstrasse 31, 8032 Zurich, Switzerland. Electronic address: michael.colla@pukzh.ch.
2 papers in the library · 11 citations · publishing 2021-2025
Ketamine's rapid antidepressant effects challenge traditional theories that focus on monoaminergic pathways. Current research explores mechanisms including glutamatergic disinhibition, neurotrophic, and neuroplastic effects. Despite extensive study, ketamine has not yet led to new therapies beyond itself, and significant knowledge gaps and study limitations remain.
A higher percentage of EEG vigilance stage A1, a measure of brain activity, is associated with response to intravenous ketamine in major depression. In a phase-2 randomized controlled trial of oral prolonged-release ketamine for treatment-resistant depression, no significant interaction between response and treatment was found for this EEG marker. However, a small-scale meta-analysis showed a significant pooled mean difference between ketamine responders and non-responders. Applying a previously proposed A1 cutoff of 43% yielded chance-level prediction accuracy in the combined ketamine group but 75% accuracy in the 240 mg subgroup. Responders to 240 mg ketamine also showed more stable vigilance over time. These findings support EEG vigilance as a predictive biomarker for treatment outcomes in depression, though further validation is needed.