Patarroyo-Rodríguez, Liliana

Background: Ketamine and esketamine ((es)ketamine) rapidly reduce depressive symptoms and suicidal ideation (SI) in treatment-resistant depression (TRD), but whether early SI improvement during the acute phase of the treatment predicts reduced suicide-associated emergency department (SAED) visits over the longer term remains unclear. Objectives: To examine whether early improvements in SI, measured using item 12 of the Quick Inventory of Depressive Symptomatology – Self Reported (QIDS-SR), following (es)ketamine treatment are associated with SAED visits over 6 months Design: Retrospective cohort study. Methods: Individuals with TRD who had available data on SI measured using the QIDS-SR during the acute phase, as well as data on SAED visits over 6 months, were included. Participants were classified based on changes in SI as resolved, partially improved, or unchanged/worsened using the QIDS-SR item 12 during acute treatment (up to six intravenous (IV) or eight intranasal (IN) treatments) and were followed for SAED visits. Results: Among 96 patients with SI data, 73 (76%) had baseline SI. Following acute-phase treatment, 36 (49%) achieved SI resolution, 14 (19%) partially improved, and 23 (32%) were unchanged/worsened. During the 6-month follow-up, 8 (11%) had post-acute SAED visits. While not statistically significant, patients with resolved SI had lower odds of post-acute ED visits (OR = 0.16, p = 0.12). Kaplan–Meier estimates of SAED visit-free survival across three SI change groups trended toward significance ( p = 0.066), suggesting lower cumulative healthcare (ED) utilization in more favorable change groups. Secondary analysis among 57 patients who received IV ketamine and had baseline SI showed that, after two infusions, 33 (47.2%) demonstrated a reduction in SI. Early SI improvement (⩾50% reduction in SI) was associated with a lower likelihood of any post-treatment SAED visit at 6 months after adjusting for pre-treatment SAED (OR = 0.17, 95% CI: 0.02–0.98, p = 0.047), corresponding to numbers needed to treat of 4.3. Conclusion: Early SI changes may have prognostic implications, though larger studies are needed to confirm clinical significance.

Background: Depression affects approximately 5.7% of adults worldwide, and around one-third of these individuals develop treatment-resistant depression (TRD). Intravenous (IV) ketamine and esketamine (administered IV or intranasally (IN)) are novel treatment options for TRD; however, only IN esketamine currently holds FDA approval. Objectives: Compare the acute effectiveness of IV ketamine with esketamine (IV or IN) in adults with TRD. Design: Mantel–Haenszel random-effects meta-analysis of head-to-head studies. Response and remission at study end point were co-primary outcomes, expressed as odds ratios (ORs) with 95% confidence intervals (CIs). Subgroup and sensitivity analyses explored the impact of diagnosis, study type, and publication format; heterogeneity was quantified with I 2 . Data sources and methods: MEDLINE, Embase, Cochrane, APA Psycinfo, and Scopus were searched from inception through 19 March 2025. Eligible studies enrolled adults with unipolar or bipolar depression directly comparing IV ketamine with esketamine and reporting response or remission. Results: Screening 1089 records identified eight studies ( n = 978). Seven observational studies ( n = 915) comparing IV ketamine with IN esketamine were included in the meta-analysis, while one randomized controlled trial (RCT) comparing IV formulations was summarized qualitatively. Pooled response from six studies gave OR = 1.26 (95% CI, 0.92–1.71; p = 0.15) and remission from seven studies gave OR = 1.31 (95% CI, 0.93–1.86; p = 0.12), both nonsignificantly favoring IV ketamine with negligible heterogeneity ( I 2 = 0%). Sensitivity analyses excluding bipolar depression or abstract-only reports yielded similar effect estimates, reinforcing the robustness of the findings. Evidence across three studies for faster onset with IV ketamine ranged from significant in one study to modest trends in two. Conclusion: Based on the currently available comparative evidence, which is almost entirely observational, IV ketamine and IN esketamine show comparable acute response and remission rates, though IV ketamine may act faster. Large head-to-head RCTs are needed to confirm these findings. Trial registration: The study protocol was prospectively registered on the Open Science Framework (OSF) at https://osf.io/5jzev .