Table 3.

Ketamine effects on explicit and implicit suicidality

Measure	Single Infusion Study (n=26)		IAT Subsample (n=10)		Repeated Infusions Study (n=10)

	Mean (SD)	Effect Size: Cohen’s d [95% CI]	Mean (SD)	Effect Size: Cohen’s d [95% CI]	Mean (SD)	Effect Size: Cohen’s d [95% CI]

MADRS total
Baseline	36.92 (5.41)		37.80 (5.8)		32.70 (6.43)
Day 2: 24-hours after infusion 1	14.85 (13.14)^***	d=2.11 [1.25–2.97]	9.40 (8.9)^***	d=3.79 [1.21–6.37]	8.10 (4.63)^***	d=4.43 [0.89–7.97]
Day 12: 4-hours after infusion 6	--	--	--	--	5.11 (3.66)^*** ^†	d=5.98 [1.52–10.44]

MADRS-SI
Baseline	2.85 (1.6)		2.90 (1.7)		3.00 (1.63)
Day 2: 24-hours after infusion 1	0.77 (1.4)^***	d=1.37 [0.79–1.95]	0.40 (.97)^***	d=1.67 [0.70–2.64]	0.20 (0.63)^***	d=2.17 [0.75–3.59]
Day 12: 4-hours after infusion 6	--	--	--	--	0.00 (0.00)^*** ^†	d=2.42 [1.20–3.63]

BSI
Baseline	--	--	8.00 (9.3)		--	--
Day 2: 24-hours after infusion 1	--	--	3.3 (7.8)^*	d=0.53 [0.18–0.87]	--	--

IAT: Escape=Me
Baseline	--	--	−.04 (.31)		--	--
Day 2: 24-hours after infusion 1	--	--	−.53 (.40)^**	d=1.36 [0.38–2.34]	--	--

IAT: Death=Me
Baseline	--	--	−.48 (.63)		--	--
Day 2: 24-hours after infusion 1	--	--	−.28 (.43) (ns)	d=−0.38 [−1.56–0.79]	--	--

Note: TRD = treatment-resistant depression; MADRS = Montgomery-Asberg Depression Rating Scale (16); MADRS-SI = MADRS Suicidality Item; BSI = Beck Scale for Suicidal Ideation (17); IAT = Implicit Association Test (5)

^***

p <.001;

^**

p < .01;

p < .05; ns = not significant; baseline and post-infusion scores compared by paired t-tests; baseline-to-post infusion effect size (d) calculated from means, SDs, and pre-post correlation coefficients (20)

^†

n=9 for Day 12 assessments