A patient with bipolar treatment-resistant depression who had not responded to medication, psychotherapy, or either repetitive transcranial magnetic stimulation (rTMS) or intravenous ketamine alone achieved complete and sustained remission when rTMS and ketamine were used together. The authors discuss how the two treatments may have complementary antidepressant mechanisms and call for further research on the combination's feasibility, tolerability, and efficacy.
A systematic review of 21 studies involving approximately 900–1,180 participants with treatment-resistant depression found that low-dose intravenous ketamine preserves and enhances certain cognitive functions. Improvements were frequently observed in processing speed and working memory, while attention remained stable or modestly improved. Results for verbal and visual memory varied across studies. Executive control, especially inhibitory performance on Stroop tasks, improved in several trials. No cognitive worsening was reported. Two studies directly examined cognition in relation to suicidal behaviors, suggesting that procognitive effects, particularly in executive control, may mediate ketamine's antisuicidal action. Standardized longitudinal studies are needed to clarify durability and clinical significance.