Supplementary Material for: A Randomized Controlled Trial on the Efficacy of Ketamine vs. Electroconvulsive Therapy in Severe Depression with Suicidal Ideation

Background: Severe depressive episodes with suicidal ideation present major therapeutic challenges and often require interventions beyond standard antidepressant therapy. Electroconvulsive therapy (ECT) remains a cornerstone treatment for refractory depression, while ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, has emerged as a rapid-acting antidepressant with potential benefits in reducing suicidal ideation. This study compares the efficacy, onset of action, and tolerability of intravenous ketamine and ECT as adjunctive treatments in severe major depressive disorder with active suicidal ideation. Methods: A randomised controlled trial was conducted at a tertiary care psychiatry department in India, enrolling 64 patients aged 18–60 years with severe depression (HAM-D ≥ 19, SSI ≥ 4). Participants were randomly assigned to receive either intravenous ketamine (n = 31) or ECT (n = 33), alongside ongoing oral antidepressants. Both groups underwent six treatment sessions over two weeks. Outcomes were assessed at baseline, post-treatment, and four weeks after completion. Primary endpoints included changes in depression severity (HAM-D) and suicidal ideation (SSI), while secondary outcomes included response and remission rates, as well as safety and tolerability profiles. Results: Both ECT and ketamine significantly reduced depressive symptoms and suicidal ideation (p < 0.001). HAM-D scores declined from 27 to 1 in the ECT group and from 26 to 2 in the ketamine group by the 4-week follow-up. SSI scores showed parallel improvement, from 12.1 to 1.2 with ECT and 12.6 to 2.0 with ketamine. Ketamine demonstrated a faster onset of clinical improvement, while ECT showed slightly greater durability of response. Side effects were mild in both groups, though ECT was associated with transient cognitive impairment, whereas ketamine produced minor dissociative and urinary symptoms. Conclusion: Ketamine offers a faster reduction in suicidal ideation than ECT, making it a promising acute intervention. Both are effective, safe adjunctive therapies, with treatment choice guided by patient profile and tolerability.

背景：伴有自杀意念的重度抑郁发作是临床治疗的重大难点，往往需要超出常规抗抑郁治疗的干预手段。电抽搐治疗（Electroconvulsive Therapy，ECT）仍是难治性抑郁的核心治疗手段；而氯胺酮——一种N-甲基-D-天冬氨酸（NMDA）受体拮抗剂——已被证实为快速起效的抗抑郁药物，在降低自杀意念方面具有潜在获益。本研究对比了静脉输注氯胺酮与ECT作为辅助治疗手段，用于伴有活动性自杀意念的重度抑郁症患者的疗效、起效时间与耐受性。方法：本研究在印度某三级精神科开展一项随机对照试验，共纳入64名年龄18~60岁的重度抑郁患者（汉密尔顿抑郁量表[Hamilton Depression Rating Scale，HAM-D]得分≥19，自杀意念量表[Suicidal Ideation Scale，SSI]得分≥4）。受试者被随机分配至静脉氯胺酮组（n=31）或ECT组（n=33），两组均联合持续口服抗抑郁药物治疗。两组均在2周内完成6次治疗。分别在基线、治疗结束时及治疗结束后4周对结局指标进行评估。主要终点包括抑郁严重程度（HAM-D）与自杀意念（SSI）的变化情况；次要终点则包括应答率与缓解率，以及安全性与耐受性特征。结果：ECT与氯胺酮均能显著改善抑郁症状与自杀意念（p<0.001）。至4周随访时，ECT组HAM-D得分从27分降至1分，氯胺酮组则从26分降至2分。SSI得分亦呈现平行改善趋势：ECT组从12.1分降至1.2分，氯胺酮组从12.6分降至2.0分。氯胺酮的临床症状改善起效更快，而ECT的应答持续时间略长。两组不良反应均较轻微，但ECT可引发一过性认知功能损害，而氯胺酮则会导致轻度的分离症状与泌尿系统症状。结论：氯胺酮降低自杀意念的速度快于ECT，是一种极具前景的急性干预手段。二者均为有效且安全的辅助治疗方案，临床选择需结合患者个体特征与耐受性进行决策。