Extended Data Table 3 Mean differences in primary outcomes at post-intervention, 6-month, and 12-month follow-ups among participants (n = 4140)

From: School-based suicide prevention using the gatekeeper programme: a cluster-randomized trial

  1. For each outcome (stigma, suicide literacy, perceived competence, and willingness to intervene), the table presents group means (SDs) at each follow-up time point, together with unadjusted and covariate-adjusted between-group mean differences (intervention minus control) and their 95% confidence intervals, as well as standardized effect sizes (Cohen’s d) and associated P values. Adjusted mean differences were estimated from linear mixed-effects models including group, time, and their interaction as fixed effects, with age, gender, education level, family income, religion, years of work, and baseline outcome scores entered as covariates. Two-sided P values were adjusted in each model for multiple comparisons using the false discovery rate (FDR) correction.
  2. At the 12-month follow-up, significant improvements were observed in all four primary outcomes for the intervention group compared to the control group. For stigma, the intervention group demonstrated substantial reductions: at the post-test, the adjusted mean difference was -4.28 (95% CI: [-4.60, -3.95], PFDR < 2.0×10−16). At the 6-month follow-up, the reduction = -2.40 (95% CI: [-2.70, -1.99], PFDR < 2.0×10−16). By 12 months, the adjusted mean difference = -1.72 (95% CI: [-2.08, -1.37], PFDR < 2.0×10−16). Suicide literacy also improved significantly, with the intervention group showing increases at all time points: at post-test, the adjusted mean difference = 3.16 (95% CI: [2.97, 3.35], PFDR < 2.0×10−16). At 6 months, the mean difference = 1.82 (95% CI: [1.62, 2.02], PFDR < 2.0×10−16). At 12 months, the adjusted mean difference = 1.62 (95% CI: [1.42, 1.82], PFDR < 2.0×10−16).
  3. In terms of competence, the intervention group reported substantial increases: at post-test, the adjusted mean difference = 12.00 (95% CI: [11.20, 12.80], PFDR < 2.0×10−16). At the 6-month follow-up, the mean difference = 6.02 (95% CI: [5.30, 6.75], PFDR < 2.0×10−16). By 12 months, the adjusted mean difference = 5.39 (95% CI: [4.66, 6.80], PFDR < 2.0×10−16). Finally, for willingness to intervene, the intervention group showed substantial improvements, with an adjusted mean difference = 11.20 (95% CI: [10.30, 12.10], PFDR < 2.0×10−16). At 6 months, the adjusted mean difference = 5.91 (95% CI: [4.96, 6.86], PFDR < 2.0×10−16). At 12 months, the adjusted mean difference = 5.84 (95% CI: [4.88, 6.80], PFDR < 2.0×10−16). These findings suggest that the LGTP intervention significantly improved stigma reduction, suicide literacy, competence, and willingness to intervene, with sustained effects over time.
Back to article page