Key Takeaways
Extended Takeaways
- In the 38 patients with outcome data, depressive symptoms improved substantially across the acute series, with mean MADRS scores decreasing from 31.1 to 19.2 and mean QIDS scores decreasing from 17.8 to 10.7, supporting measurable benefit even in a clinically heterogeneous, treatment-resistant bipolar depression sample.
- Most patients received ketamine or esketamine alongside standard bipolar treatments rather than as monotherapy: 40/45 (88.9%) were on an antipsychotic, lithium, or a mood stabilizer/anticonvulsant, and 23/45 (51.1%) were also taking an antidepressant during the acute series.
- When affective switch occurred, it was typically delayed rather than early, with the mean time from first ketamine/esketamine treatment to the initial hypomanic/manic event being 297 days and the median time 266 days; this argues for continued monitoring during maintenance treatment, not just during induction.
- Affective switch was not limited to patients who were unprotected by mood-stabilizing therapy: 14 (87.5%) of manic/hypomanic events occurred when the patient was on a mood stabilizer, antipsychotic, or lithium.
- Only 1 patient required psychiatric hospitalization for severe mania; by contrast, 8/16 episodes were mild hypomania that resolved without intervention and 7 episodes of moderate hypomania resolved with medication adjustment, suggesting that most emergent symptoms in maintenance treatment were clinically manageable.
- Treatment exposure differed by formulation in this real-world cohort, with a median treatment duration of 4.0 months for esketamine versus 1.9 months for ketamine, which may be relevant when interpreting maintenance-phase safety observations.
