Fig. 4

(a) Relation between insomnia severity and internet gaming disorder (R² = .252); (b) Relation between internet gaming disorder and psychoticism (R² = .455); (c) Total effect of insomnia severity on psychoticism (R² = .444); (c’) Direct effect of insomnia severity on psychoticism. Numbers are displayed as regression coefficients (standard error). *p < 0.05; **p < 0.01; ***p < 0.001