Significance Statement
major depression, chronic suicidality
Our study is the first, to our knowledge, to examine electrophysiological changes in adults with major depression and chronic suicidality following a low-dose ketamine treatment with oral administration. While previous studies have confirmed the feasibility and tolerability of oral ketamine as a treatment for chronic suicidality, the present study reports significant changes in the spectral properties of EEG. Alpha band power displayed changes throughout the trial, during the active treatment phase, and after the treatment had ended. Theta and low-beta band powers showed changes only after the treatment period had ended, between posttreatment and later follow-up. Theta band also correlated the most with clinical symptoms.