TABLE 3.
Mediation statistics for mediators of relationship between treatment group and change in SIcomposite
| M: | Path a: Treatment->M | Path b: M->SIcomposite (controlling for treatment) | Path a ×b: Treatment->M-> SIcomposite |
|---|---|---|---|
| Measures collected concurrently with SIcomposite (baseline and 24 hr) | |||
| Change in MADRSnonSI | b = 8.8; t56 = 3.5; R2 = .18; P < 001 | b = .10; t53 = 3.6; R2 = .19; P < 001 | b = .90; t53 = 2.3; R2 = .09; P = .001 |
| Change in BHS | b = 2.6; t53 = 1.6; R2 = .11; P = .09 | b = .16; t53 = 3.0; R2 = .15; P = .002 | b = .43; t53 = 1.3; R2 = .03; P = .12 |
| Change in STAI-S | b = 3.7; t53 = .85; R2 = .01; P = .38 | b = .03; t53 = .88; R2 = .01; P = .42 | b = .16; t53 = .61; R2 = .01; P = .68 |
| Change in Escape = Me IAT | b = .13; t53 = 1.0; R2 = .02; P = .33 | b = .05; t53 = .09; R2 < .01; P = .96 | b = .01; t53 = .07; R2 < .01; P = .91 |
| Change in Death = Me IAT | b = .12; t53 = .76; R2 = .01; P = .44 | b = .58; t53 = .83; R2 = .01; P = .43 | b = .05; t53 = .34; R2 < .01; P = .31 |
| Measures temporally preceding change in SIcomposite | |||
| Change in MADRSnonSI baseline to 4 hr |
b = 6.1; t56 = 2.6; R2 = .11; P = .009 | b = .08; t56 = 2.1; R2 = .07; P = .02 | b = .48; t56 = 1.6; R2 = .04; P = .04 |
| Change in VAS-Euphoric: baseline to 40 min |
b = 2.2; t56 = 3.4; R2 = .17; P < 001 | b = .23; t56 = 2.0; R2 = .07; P = .06 | b = .52; t56 = 1.7; R2 = .05; P = .09 |
| Change in CADSS: baseline to 40 min |
b = 14.8; t56 = 5.9; R2 = .38; P < 001 | b = .04; t56 = .99; R2 = .02; P = .46 | b = .67; t56 = .98; R2 = .02; P = .49 |
Note: Paths with P < .05, unadjusted (derived via bootstrapping) appear in bold; paths with P < .10, unadjusted appear in bold italics; X = group (ketamine vs. midazolam), M = mediator (found in column 1), Y = change in composite suicidal ideation index (SIcomposite). Path c, which was held constant across all analyses (the effect of treatment group on change in SIcomposite), was also significant (b = 1.7; t56 = 2.6; P = .009); therefore mediation criteria are met when path’s a, b and a × b are all significant. MADRS-SI, Montgomery-Asberg Depression Rating Scale (16) Suicidality Item; MADRSnonSI, sum of all other MADRS items, sleep and appetite items carried forward from baseline; BHS, Beck hopelessness scale; STAI-S, Spielberger State-Trait Anxiety Inventory, State Form; IAT, implicit association test (5).