Comparative Efficacy of Ketamine in Treatment-Resistant Depression

Patients who have not responded to two antidepressant trials in their current depressive episode are usually considered to have treatment-resistant depression (TRD). A detailed search on PubMed was conducted for reported response and remission rates for non-ketamine and ketamine treatments for TRD. From a variety of pharmacological and brain stimulation open-label studies, the treatments were found to have similar response and remission rates of 30% to 70% and 20% to 50%, respectively. For randomized placebo-controlled trials, reported response and remission rates were 15% to 60% and 10% to 40%, respectively. Ketamine and electroconvulsive therapy both have response and remission rates at the higher end of these ranges, and their significant advantage is their fast action in an acute setting. Direct comparative efficacy studies with large sample sizes will be needed to establish any margin of increased benefit of one treatment modality compared to the other.