In patients with treatment-resistant bipolar disorder, intravenous ketamine (average dose 0.8 mg/kg) significantly reduced depressive symptoms, including inner tension, sleep reduction, and suicidal ideation, over four weeks without triggering manic switches. Fifty-nine patients were treated consecutively, and improvements in Montgomery-Åsberg Depression Rating Scale scores were observed from the second week onward. Adverse events were generally mild to moderate. The findings suggest ketamine can be a well-tolerated option for bipolar depression when carefully monitored, though caution is warranted due to the inherent risk of mood switching in bipolar disorder.
In a real-world clinic, intravenous ketamine reduced depressive symptoms in patients with treatment-resistant unipolar and bipolar depression. Both groups improved significantly, but those with bipolar depression showed faster and greater improvement starting at two weeks and lasting through three months. Dissociative side effects were mild and did not increase over time; women with unipolar depression reported higher dissociative symptoms at three months. No sex differences in antidepressant efficacy were found. The findings suggest ketamine is effective for treatment-resistant depression, with stronger benefits for bipolar depression.