TABLE 2.
Ketamine effects on explicit and implicit suicidality and related measures
| Ketamine (n = 36)a |
Midazolam (n = 21)a |
|||
|---|---|---|---|---|
| Measure | Mean (SD) | Within-groups effect size: Cohen’s d [95% CI] |
Mean (SD) | Within-groups effect size: Cohen’s d [95% CI] |
| SIcomposite | ||||
| Baseline | 0.15 (2.66) | d = 1.06 [0.57–1.55] | −0.21 (2.12) | d = 0.29 [0.01–0.57] |
| 24 hr post infusion | −2.23 (1.63)***§ | −0.91 (2.52)*§ | ||
| BSS | ||||
| Baseline | 6.11 (6.76) | d = 0.88 [0.45–1.30] | 6.19 (6.68) | d = 0.34 [0.05–0.63] |
| 24 hr post infusion | 1.13 (2.65)*** | 3.95 (6.46) | ||
| MADRS-SI | ||||
| Baseline | 1.61 (1.37) | d = 0.72 [0.27–1.17] | 1.48 (1.03) | d = 0.20 [−0.16 –0.58] |
| 24 hr post infusion | 0.72 (1.05)*** | 1.24 (1.26) | ||
| QIDS-SI | ||||
| Baseline | 0.97 (0.84) | d = 1.04 [0.56–1.51] | 0.76 (0.76) | d = 0.18 [−0.18–0.56] |
| 24 hr post infusion | 0.22 (0.54)*** | 0.62 (0.74) | ||
| BHS | ||||
| Baseline | 12.79 (4.92) | d = 0.90 [0.52–1.27] | 10.65 (5.85) | d = 0.49 [0.05–0.93] |
| 24 hr post infusion | 7.20 (6.48)*** | 7.65 (6.25)* | ||
| STAI-S | ||||
| Baseline | 58.97 (9.70) | d = 1.21 [0.74–1.69] | 57.50 (9.82) | d = 0.98 [0.37–1.60] |
| 24 hr post infusion | 41.91 (16.31)*** | 44.10 (15.93)*** | ||
| IAT: Escape = Me | ||||
| Baseline | −0.25 (0.40) | d = 0.58 [0.09–1.07] | −0.36 (0.34) | d = 0.09 [−0.47–0.66] |
| 24 hr post infusion | −0.48 (0.39)** | −0.39 (0.32) | ||
| IAT: Death = Me | ||||
| Baseline | −0.39 (0.45) | d = −0.06 [0.41–0.28] | −0.54 (0.47) | d = −0.37 [0.98–0.23] |
| 24 hr post infusion | −0.36 (0.48) | −0.39 (0.30) | ||
Note: SIcomposite, composite explicit suicidal ideation index; BSS, Beck scale for suicidal ideation (17); MADRS-SI = Montgomery-Asberg Depression Rating Scale (16) Suicidality Item; QIDS-SI, quick inventory of depressive symptoms suicidality item; BHS, Beck hopelessness scale; STAI-S, Spielberger state-trait anxiety inventory, state form; IAT, implicit association test (5).
Within-groups baseline and post-infusion scores compared by paired t-tests with bootstrapping significance test; for non-primary outcomes, multiple comparisons correction applied separately across explicit measures (5 measures) and implicit measures (2 measures); baseline-to-post infusion effect size (d) calculated from means, SDs, and pre-post correlation coefficients (20).
P ≤ .001 (primary outcome)
P < .05 (primary outcome)
P ≤ .002 unadjusted for multiple comparisons, P ≤ .01 adjusted
P = .01 unadjusted, P = .02 adjusted
P < .05 unadjusted, P < .25 adjusted.
Total n reduced to 54 for IAT, BHS, and STAI-S.