Interoception mediates the association between social support and sociability in patients with major depressive disorder

Table 1 Demographic data for participants

Variable	MD (n = 292)	HC (n = 257)	Test statistic
Age (years), M (p25, p75)	25.0 (20.0-34.8)	24.0 (22.0-28.5)	z = -0.7826, P = 0.434
Gender (female), n (%)	183 (62.7)	160 (54.8)	χ2 = 0.0100, P = 0.920
Height (cm), M (p25, p75)	167.0 (162.0-172.0)	165.0 (160.0-173.0)	z = -0.0508, P = 0.960
Weight (kg), M (p25, p75)	58.0 (50.0-69.8)	60.0 (53.0-70.0)	z = -1.2459, P = 0.213
Education (year), M (p25, p75)	14.0 (12.0-16.0)	16.0 (15.0-18.0)	z = -10.2783, P < 0.001
Physical activity, M (p25, p75)	4.0 (1.0-12.0)	8.0 (3.0-18.0)	z = -4.7502, P < 0.001
Depression state (mean ± SD)	19.0 (14.0-23.0)	1.0 (0-2.0)	z = -20.3641, P < 0.001
Anxiety state (mean ± SD)	12.0 (9.0-16.0)	1.0 (0-2.0)	z = -19.6389, P < 0.001
Disease course (month) (mean ± SD)	40.7 (56.8)
BMI, n (%)
< 18.5	74 (25.3)	29 (11.3)	χ2 = 33.5618, P < 0.001
18.5-23.9	190 (65.1)	164 (63.8)
> 23.9	28 (9.6)	64 (24.9)
Annual household income (CNY), n (%)
< 100000	65 (22.3)	114 (44.4)	χ2 = 33.4600, P < 0.001
100000-300000	186 (63.7)	126 (49.01)
300000-500000	32 (11.0)	15 (5.8)
> 500000	9 (3.1)	2 (0.8)
Social media usage (hours), n (%)
< 3 hours	48 (16.4)	42 (16.3)	χ2 = 13.6544, P = 0.003
3-5 hours	93 (31.9)	99 (39.0)
5-8 hours	67 (23.0)	75 (29.2)
> 8 hours	84 (28.8)	41 (16.0)
SSRS scores	31.38 (8.06)	41.11 (9.09)	t = 13.2741, P < 0.001
TSBI scores	80.3 (17.2)	98.6 (14.8)	t = 13.2293, P < 0.001

MD: Major depression; HC: Health control; SSRS: Social support rating scale; TSBI: Texas social behavior inventory; M: Median and interquartile range; p25: 25^th percentile; p75: 75^th percentile; BMI: Body mass index; CNY: Chinese yuan.

Table 2 Analysis of mediating effect in major depression group

Independent variable	Mediator	Total effect		Indirect effect		Direct effect		Proportion mediated (%) (95%CI)
		95%CI	P value	95%CI	P value	95%CI	P value
SSRS scores	Noticing	0.77 (0.55 to 0.97)	< 0.001	0.00 (-0.01 to 0.03)	0.820	0.77 (0.55 to 0.97)	< 0.001	0.1 (-2.0 to 3.2)
	Not-distracting	0.77 (0.55 to 0.97)	< 0.001	0.00 (-0.02 to 0.02)	0.821	0.77 (0.56 to 0.97)	< 0.001	-0.1 (-3.2 to 2.1)
	Not-worrying	0.77 (0.55 to 0.98)	< 0.001	0.01 (-0.01 to 0.04)	0.501	0.76 (0.55 to 0.97)	< 0.001	0.7 (-1.5 to 4.8)
	Attention regulation	0.77 (0.56 to 0.98)	< 0.001	0.04 (-0.00 to 0.10)	0.084	0.73 (0.52 to 0.93)	< 0.001	5.0 (-0.6 to 12.7)
	Emotional awareness	0.77 (0.55 to 0.98)	< 0.001	0.03 (0.00 to 0.08)	0.036	0.73 (0.52 to 0.94)	< 0.001	3.9 (0.2 to 11.1)
	Self-regulation	0.77 (0.56 to 0.98)	< 0.001	0.08 (0.02 to 0.15)	0.008	0.69 (0.48 to 0.89)	< 0.001	9.6 (2.6 to 19.4)
	Body listening	0.77 (0.56 to 0.98)	< 0.001	0.06 (0.01 to 0.12)	0.016	0.71 (0.50 to 0.91)	< 0.001	7.0 (1.3 to 15.5)
	Trust	0.77 (0.55 to 0.97)	< 0.001	0.06 (0.01 to 0.13)	0.008	0.70 (0.48 to 0.91)	< 0.001	7.8 (1.8 to 16.8)

The mediation analysis were adjusted for basic information-age, gender, years of education, daily use of electronic devices such as mobile phones, pads, and computers for entertainment, total household income, body mass index, exercise, rapid screening for depression, anxiety screening, and disease course. CI: Confidence interval; SSRS: Social support rating scale.

Table 3 Analysis of mediating effect in health control group

Independent variable	Mediator	Total effect		Indirect effect		Direct effect		Proportion mediated (%) (95%CI)
		95%CI	P value	95%CI	P value	95%CI	P value
SSRS scores	Noticing	0.52 (0.34 to 0.72)	< 0.001	0.00 (-0.02 to 0.03)	0.841	0.52 (0.33 to 0.72)	< 0.001	0.3 (-4.7 to 6.3)
	Not-distracting	0.52 (0.32 to 0.72)	< 0.001	0.02 (-0.01 to 0.07)	0.228	0.49 (0.30 to 0.69)	< 0.001	4.0 (-2.8 to 13.7)
	Not-worrying	0.52 (0.32 to 0.72)	< 0.001	0.00 (-0.03 to 0.01)	0.660	0.52 (0.33 to 0.73)	< 0.001	-0.6 (-6.4 to 2.1)
	Attention regulation	0.52 (0.34 to 0.72)	< 0.001	0.07 (0.00 to 0.16)	0.048	0.45 (0.27 to 0.64)	< 0.001	13.7 (0.3 to 29.3)
	Emotional awareness	0.52 (0.34 to 0.72)	< 0.001	0.05 (0.00 to 0.12)	0.048	0.47 (0.28 to 0.67)	< 0.001	9.6 (0.5 to 22.5)
	Self-regulation	0.52 (0.34 to 0.72)	< 0.001	0.08 (0.01 to 0.17)	0.036	0.44 (0.26 to 0.63)	< 0.001	15.6 (2.8 to 31.8)
	Body listening	0.52 (0.34 to 0.72)	< 0.001	0.05 (-0.02 to 0.13)	0.201	0.48 (0.30 to 0.67)	< 0.001	8.5 (-4.6 to 22.5)
	Trust	0.52 (0.34 to 0.72)	< 0.001	0.10 (0.03 to 0.19)	0.004	0.42 (0.24 to 0.61)	< 0.001	19.1 (7.1 to 37.0)

The mediation analysis were adjusted for basic information-age, gender, years of education, daily use of electronic devices such as mobile phones, pads, and computers for entertainment, total household income, body mass index, exercise, rapid screening for depression, anxiety screening, and disease course. CI: Confidence interval; SSRS: Social support rating scale.