A preliminary study of anti-suicidal efficacy of repeated ketamine infusions in depression with suicidal ideation

Background: Suicide is a tremendous public health crisis and is demanded urgent intervention. Previous studies found that ketamine intervention could rapidly reduce suicidal ideation in depression. However, the comparatively study in Chinese population remains absence. The current study aims to assess the anti-suicidal efficacy of repeated ketamine infusions for Chinese depressed suicidal patients, especially distinguish between low suicidal ideation (SI) group and high SI group. Methods: Eighty-six unipolar and bipolar depressive patients with current suicidal ideation received six ketamine infusions during a 12-day period. Hamilton Depression Rating Scale (HAMD) and Beck Scale for Suicide Ideation (SSI) was measured at baseline, 4 h and 24 h after each infusion, and two-week naturalistically follow-up. Results: Forty-nine (57.0%) patients relief of suicidal ideation after first infusion and 56 (65.1%) after six infusions. Anti-suicidal response rate in low SI group were higher than high SI group, and anti-suicidal response at 4 h after first infusion was significant predictor of response at 24 h after sixth infusion. Furthermore, at 24 h after the sixth infusion, correlation between changes in suicidal ideation and depression was 0.23, accounting for 7.4% in the variance of suicidal ideation change. Limitation: The major limitation of this study was that lack of a placebo or other control group limits the interpretation of efficacy. Conclusions: We confirmed that six repeated ketamine infusions for Chinese suicidal depressed patients were effective in generating a rapid response of suicidal ideation, especially low SI achieved more benefits from ketamine infusions.