Comparing the Cognitive Effects of Repeated Intravenous Ketamine and Electroconvulsive Therapy in Patients With Treatment-Resistant Depression
The Journal of Clinical Psychiatry September 3, 2025 Kristina T. Kumpf, Samuel T. Wilkinson, Bo Hu et al.
In a multisite randomized trial comparing cognitive effects of intravenous ketamine and electroconvulsive therapy (ECT) in patients with treatment-resistant depression, those receiving six ketamine treatments showed superior cognitive functioning after a three-week treatment course compared with those receiving nine ECT sessions. No significant differences in cognitive task performance were associated with response to either treatment. Among responders followed for up to six months, no group differences emerged. Subjective memory measures were mixed: both groups improved on the Squire Memory Complaint Questionnaire, with ketamine recipients reporting greater functional gains, while ketamine-treated patients reported improvements on a global self-evaluation of memory but ECT-treated patients reported a decline. Within the ketamine group, improvements in executive functioning and cognitive flexibility survived adjustment for changes in depression, suggesting partial independence of cognitive and mood effects.