Study Flow Diagram
Patients are labeled as having received their allocated infusion if they initiated the infusion. For 1 single patient, who was allocated to the ketamine plus sham automated self-association training (ASAT) group, the infusion was discontinued after administration of approximately two-thirds of the intended dose, at the patient’s request. Patients are labeled as having received their allocated ASAT condition (active or sham) if they completed at least 75% of the intended 8 sessions. All but 2 of the patients labeled as having received their ASAT allocation completed the entire set of 8 sessions, per protocol. During the follow-up period, all missing data are attributable to patients who were lost to follow-up or patients who withdrew (as described under Allocation). Missing data values were automatically estimated within the presented intent-to-treat hierarchical linear models. Missingness of data did not differ as a function of treatment allocation at any time point according to χTime point and group (using saline plus ASAT as the reference group) were included as categorical factors in an intent-to-treat, hierarchical linear model (which automatically estimates missing values) estimating QIDS-SR total scores, covarying preinfusion baseline QIDS-SR scores. To dissect group × time interactions, given lack of a priori knowledge regarding potential durability of this novel intervention, visual inspection of symptom trajectories was used to identify post hoc a data-driven breakpoint at which error bars became overlapping, visible at greater than or equal to 120 days postinfusion (