Table 4.

Mediation analysis for sleep quality (N=348)

	Model 1		Model 2		Model 3		Model 4
	B (SE)	BC 95% CI (P value)	B (SE)	BC 95% CI (P value)	B (SE)	BC 95% CI (P value)	B (SE)	BC 95% CI (P value)
Model A: Sleep quality mediates the association between IGD and perceived stress
Indirect effect	0.327 (0.126)	0.079 to 0.576 (0.009)	0.299 (0.126)	0.053 to 0.545 (0.001)	0.302 (0.128)	0.047 to 0.552 (<0.001)	0.300 (0.127)	0.046 to 0.540 (0.002)
Direct effect	0.640 (0.197)	0.252 to 1.028 (0.001)	0.629 (0.212)	0.212 to 1.047 (0.003)	0.676 (0.197)	0.289 to 1.063 (<0.001)	0.682 (0.199)	0.291 to 1.074 (<0.001)
Total effect	0.967 (0.154)	0.664 to 1.271 (<0.001)	0.928 (0.179)	0.576 to 1.281 (<0.001)	0.978 (0.154)	0.669 to 1.286 (<0.001)	0.982 (0.159)	0.671 to 1.296 (<0.001)
Proportion of indirect to total effect mediated (%)	33.82		32.22		30.88		30.62
Model B: sleep quality mediates the association between IGD and suicidal behaviour
Indirect effect	0.195 (0.037)	0.125 to 0.271 (<0.001)	0.192 (0.038)	0.119 to 0.269 (<0.001)	0.192 (0.039)	0.117 to 0.274 (<0.001)	0.174 (0.038)	0.106 to 0.253 (<0.001)
Direct effect	0.476 (0.042)	0.394 to 0.559 (<0.001)	0.473 (0.042)	0.389 to 0.557 (<0.001)	0.479 (0.043)	0.394 to 0.564 (<0.001)	0.449 (0.045)	0.360 to 0.538 (<0.001)
Total effect	0.671 (0.035)	0.603 to 0.740 (<0.001)	0.665 (0.035)	0.594 to 0.737 (<0.001)	0.671 (0.036)	0.599 to 0.744 (<0.001)	0.623 (0.041)	0.543 to 0.703 (<0.001)
Proportion of indirect to total effect mediated (%)	29.06		28.87		28.61		27.93

Unadjusted mediation model: model 1; adjusted mediation models: model 2 (for sociodemographic factors), model 3 (for sociodemographic and personal factors) and model 4 (for sociodemographic, personal and gaming characteristics); B (unstandardised coefficient); BC 95% CI (based on 10 000 bootstrap samples).

BC, bias-corrected; CI, confidence interval; IGD, internet gaming disorder; SE, standard estimate.