Reductions in suicidal thoughts following ketamine infusions were associated with, but partially independent of, the improvement in depression.

Six ketamine infusions were associated with reduce suicidal ideation at as early as 4 h and rapid anti-suicidal response to the first infusion is strongly predicted a sustained response to additional infusions.

This is the first study to assess the anti-suicidal efficacy and safety of repeated ketamine infusions in Chinese suicidal depressed patients.

Abstract

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.