Table 5.

Subgroup analysis of mediation models for SDS associated with PSQI mediated by STAI in medical university students

	Indirect effect	Direct effect	Total effect	Z	Sobel p value	Proportion of total effect that is mediated
Gender
Male	1.217***	0.149	1.366***	10.884	<0.001	89.12
Female	1.117***	0.315**	1.432***	10.313	<0.001	78.01
Birthplace
Urban	1.104***	0.189	1.294***	8.411	<0.001	85.37
Rural	1.213***	0.247**	1.461***	12.521	<0.001	83.07

STAI State-Trait Anxiety Inventory, PSQI Pittsburgh Sleep Quality Index, SDS Self-rating depression scale. Sobel-Goodman Mediation Test in adjusted models for gender, birthplace, grade, major, ethnicity, only child, close relationship, education of close relationship, education of father, education of mother, job of close relationship, job of father, job of mother. Values are bolded if they achieved statistical significance at P ≤ 0.05

** p < 0.01, *** p < 0.001