The subgroup analysis comparing blind and open-label RCTs indicated that only the open-label trials showed a significant superiority of disulfiram over controls: g = .70 (95%CI = .46–.93), whereas the RCTs with blind designs showed no efficacy of disulfiram as compared to controls: g = .01 (95%CI = .−.29–.32) (Figure 3). I2 = 65% for open-label studies and I2 = 43% for blind studies. Having validated our hypothesis that a blind design is unsuitable for assessing disulfiram efficacy, we excluded the blind trials from the subsequent analyses. A visual inspection of the funnel plot for open-label studies revealed asymmetry, indicating possible publication bias. The trim-and-fill analysis indicated that there were 2 potentially missing studies on the left side of the funnel plot. Nevertheless, the summary effect-size remained significant after correcting for the supposedly missing study (adjusted effect-size g = .65 (95%CI = .42–88). The summary effect-size reached significance in all cases in the leave-one-out analysis, with summary effect-sizes varying from g = .64 to g = .75 (all p<.001). Meta-regression indicated no significant effect of publication year, disulfiram dosage, treatment duration, or risk of bias score.
