Prevalence and associated factors of depression and anxiety among doctoral students: the mediating effect of mentoring relationships on the association between research self-efficacy and depression/anxiety

Figures & data

Table 1 Sociodemographic and doctoral characteristics of respondents (n=325)

Characteristics	n	%
Sociodemographic variables	325
Age (years)
≤25	30	9.2
26–30	151	46.5
≥31	144	44.3
Sex
Male	129	39.7
Female	196	60.3
Marital status
Married/living with partner	165	50.8
Single/widowed/divorced	160	49.2
Have children
No	195	60
One or more	130	40
Income (CN¥ per month)
≤3,000	184	56.6
3,001–5,000	30	9.2
≥5,001	111	34.2
Doctoral variables
Employment before doctoral enrollment
No	160	49.2
Yes	165	50.8
Clinical doctoral student
No	193	59.4
Yes	132	40.6
Grade
First year	71	21.8
Second year	121	37.2
Third year	116	35.7
Fourth year or above	17	5.23
Frequency of meeting with mentor
At least once a week	193	59.4
At least once a month	87	26.8
Seldom	45	13.8
Difficulty in publishing doctoral qualification paper
A little bit of effort	56	17.2
Some effort	148	45.5
A lot of effort	121	37.2
Difficulty in balancing work–family–doctoral program
Almost no difficulty	98	30.2
Some difficulty	126	38.8
Great difficulty	101	31.1

Table 2 Sociodemographic and doctoral characteristics by depression (n=325)

Characteristics	Depression
	None–minimal (n=114)	Mild (n=134)	Moderate (n=38)	Moderately severe (n=26)	Severe (n=13)	P-value
Sociodemographic variables
Age (years), n (%)						0.023
≤25	15 (50.0)	11 (36.7)	3 (10.0)	1 (3.3)	0
26–30	57 (37.7)	60 (39.7)	21 (13.9)	7 (4.6)	6 (4.0)
≥31	42 (29.2)	63 (43.8)	14 (9.7)	18 (12.5)	7 (4.9)
Sex, n (%)						0.475
Male	45 (34.9)	51 (39.5)	20 (15.5)	9 (7.0)	4 (3.1)
Female	69 (35.2)	83 (42.3)	18 (9.2)	17 (8.7)	9 (4.6)
Marital status, n (%)						0.016
Married/living with partner	52 (31.5)	71 (43.0)	14 (8.5)	20 (12.1)	8 (4.8)
Single/widowed/divorced	62 (38.8)	63 (39.4)	24 (15.0)	6 (3.8)	5 (3.1)
Have children, n (%)						0.002
No	79 (40.5)	74 (37.9)	27 (13.8)	8 (4.2)	7 (3.6)
One or more	35 (26.9)	60 (46.2)	11 (8.5)	18 (13.8)	6 (4.6)
Income (CN¥ per month), n (%)						0.982
≤3,000	69 (37.5)	72 (39.1)	25 (13.6)	11 (6.0)	7 (3.8)
3,001–5,000	13 (43.3)	10 (33.3)	2 (6.7)	2 (6.7)	3 (10.0)
≥5,001	32 (28.8)	52 (46.8)	11 (9.9)	13 (11.7)	3 (2.7)
Doctoral variables
Employment before doctoral enrollment, n (%)						0.021
No	68 (42.5)	57 (35.6)	21 (13.1)	8 (5.0)	6 (3.8)
Yes	46 (27.9)	77 (46.7)	17 (10.3)	18 (10.9)	7 (4.2)
Clinical doctoral students, n (%)						0.221
No	74 (38.3)	79 (40.9)	23 (11.9)	12 (6.2)	5 (2.6)
Yes	40 (30.3)	55 (41.7)	15 (11.4)	14 (10.6)	8 (6.0)
Grade, n (%)						0.040
First year	37 (52.1)	20 (28.2)	10 (14.1)	2 (2.8)	2 (2.8)
Second year	42 (34.7)	54 (44.6)	11 (9.1)	9 (7.4)	5 (4.1)
Third year	32 (27.6)	53 (45.7)	14 (12.1)	13 (11.2)	4 (3.4)
Fourth year or above	3 (17.6)	7 (41.2)	3 (17.6)	2 (11.8)	2 (11.8)
Frequency of meeting with mentor, n (%)						0.090
At least once a week	79 (40.9)	78 (40.4)	20 (10.4)	10 (5.2)	6 (3.1)
At least once a month	25 (28.7)	38 (43.7)	10 (11.5)	9 (10.3)	5 (5.7)
Seldom	10 (22.2)	18 (40.0)	8 (17.8)	7 (15.6)	2 (4.4)
Difficulty in publishing doctoral qualification paper, n (%)						<0.001
A little bit of effort	33 (58.9)	19 (33.9)	1 (1.8)	3 (5.4)	0
Some effort	52 (35.1)	66 (44.6)	19 (12.8)	6 (4.1)	5 (3.4)
A lot of effort	29 (24.0)	49 (40.5)	18 (14.9)	17 (14.0)	8 (6.6)
Difficulty in balancing work–family–doctoral program, n (%)						0.001
Almost none	51 (52.0)	35 (35.7)	7 (7.1)	4 (4.1)	1 (1.0)
Some	36 (28.6)	59 (46.8)	18 (14.3)	8 (6.3)	5 (4.0)
Great	27 (26.7)	40 (39.6)	13 (12.9)	14 (13.9)	7 (6.9)

Table 3 Sociodemographic and doctoral characteristics by anxiety (n=325)

Characteristics	Anxiety
	None–minimal (n=151)	Mild (n=109)	Moderate (n=42)	Severe (n=23)	P-value
Sociodemographic variables
Age (years), n (%)					0.114
≤25	18 (60.0)	9 (30.0)	3 (10.0)	0
26–30	68 (45.0)	55 (36.4)	19 (12.6)	9 (6.0)
≥31	65 (45.1)	45 (31.3)	20 (13.9)	14 (9.7)
Sex, n (%)					0.801
Male	61 (47.3)	41 (31.8)	19 (14.7)	8 (6.2)
Female	90 (45.9)	68 (34.7)	23 (11.7)	15 (7.7)
Marital status, n (%)					0.249
Married/living with partner	74 (44.8)	52 (31.5)	23 (13.9)	16 (9.7)
Single/widowed/divorced	77 (48.1)	57 (35.6)	19 (11.9)	7 (4.4)
Have children, n (%)					0.265
No	95 (48.7)	68 (34.9)	21 (10.8)	11 (5.6)
One or more	56 (43.1)	41 (31.5)	21 (16.2)	12 (9.2)
Income (CN¥ per month), n (%)					0.883
≤3,000	87 (47.3)	61 (33.2)	25 (13.6)	11 (6.0)
3,001–5,000	13 (43.3)	10 (33.3)	3 (10.0)	4 (13.3)
≥5,001	51 (45.9)	38 (34.2)	14 (12.6)	8 (7.2)
Doctoral variables
Employment before doctoral enrollment, n (%)					0.429
No	79 (49.4)	54 (33.8)	19 (11.9)	8 (5.0)
Yes	72 (43.6)	55 (33.3)	23 (13.9)	15 (9.1)
Clinical doctoral students, n (%)					0.030
No	97 (50.3)	67 (34.7)	21 (10.9)	8 (4.1)
Yes	54 (40.9)	42 (31.8)	21 (15.9)	15 (11.4)
Grade, n (%)					0.525
First year	41 (57.7)	19 (26.7)	8 (11.3)	3 (4.2)
Second year	54 (44.6)	43 (35.5)	14 (11.6)	10 (8.3)
Third year	49 (42.2)	43 (37.1)	16 (13.8)	8 (6.9)
Fourth year or above	7 (41.2)	4 (23.5)	4 (23.5)	2 (11.8)
Frequency of meeting with mentor, n (%)					0.017
At least once a week	106 (54.9)	58 (30.1)	19 (9.8)	10 (5.2)
At least once a month	28 (32.2)	34 (39.1)	16 (18.4)	9 (10.3)
Seldom	17 (37.8)	17 (37.8)	7 (15.6)	4 (8.9)
Difficulty in publishing doctoral qualification paper, n (%)					<0.001
A little bit of effort	36 (64.3)	17 (30.4)	3 (5.4)	0
Some effort	73 (49.3)	54 (36.5)	14 (9.5)	7 (4.7)
A lot of effort	42 (34.7)	38 (31.4)	25 (20.7)	16 (13.2)
Difficulty in balancing work–family–doctoral program (n,%)					0.001
Almost none	58 (59.2)	30 (30.6)	9 (9.2)	1 (1.0)
Some	58 (46.0)	45 (35.7)	16 (12.7)	7 (5.6)
Great	35 (34.7)	34 (33.7)	17 (16.8)	15 (14.9)

Table 4 Correlations among age, AWAI-S, RSES, PHQ-9, and GAD-7 scores

Continuous variables	Mean	SD	1	2	3	4	5
Age (years)	31.09	5.27	1
AWAI-S	113.9	18.53	−0.046	1
RSES	329.8	68.74	−0.153**	0.300**	1
PHQ-9	7.32	5.92	0.110*	−0.328**	−0.293**	1
GAD-7	5.85	5.44	0.061	−0.311**	−0.325**	0.880**	1

Note:

* P<0.05;

** P<0.01.

Abbreviations: AWAI-S, Advisory Working Alliance Inventory-student version; GAD, Generalized Anxiety Disorder; PHQ, Patient Health Questionnaire; RSES, Research Self-Efficacy Scale.

Table 5 Factors related to depression using hierarchical regression analysis

Controlled, dependent and mediating variables in the three Step Regression	PHQ-9 scores
	Step 1 (b)	Step 2 (b)	Step 3 (b)
Step 1
Age (years)	−0.105	−0.078	−0.098
Have childrena	0.035	0.044	0.112
Employment before doctoral enrollmentb	−0.024	−0.071	−0.080
Clinical doctoral studentsc	0.067	0.042	0.063
Grade
Second year vs first year	0.023	0.029	0.011
Third year vs first year	0.044	0.042	0.008
Fourth year or above vs first year	0.136*	0.147*	0.129*
Frequency of meeting with mentor
At least once a month vs at least once a week	0.133*	0.121*	0.118*
Seldom vs at least once a week	0.119*	0.093	0.049
Difficulty in publishing doctoral qualification paper
Some effort vs a little bit of effort	0.141	0.130	0.084
A lot of effort vs a little bit of effort	0.325***	0.276***	0.265***
Difficulty in balancing work–family–doctoral program
Some vs almost none	0.161*	0.141*	0.118
Great vs almost none	0.256***	0.231**	0.195**
Step 2
RSES		−0.211***	−0.136*
Step 3
AWAI-S			−0.257***
F	5.054***	5.958***	7.419***
Adjusted R^2	0.142	0.179	0.232
∆R^2	0.177***	0.038***	0.053***

Notes:

a 1, Have no children; 2, have one or more children.

b 1, Not employed before doctoral enrollment; 2, employed before doctoral enrollment.

c 1, Not clinical doctoral students; 2, clinical doctoral students. Grade, doctoral grade.

* P<0.05 (two-tailed);

** P<0.01 (two-tailed);

*** P<0.001 (two-tailed).

Abbreviation: PHQ, Patient Health Questionnaire.

Table 6 Factors related to anxiety using hierarchical regression analysis

Controlled, dependent and mediating variables in the three Step Regression	GAD-7 scores
	Step 1 (b)	Step 2 (b)	Step 3 (b)
Step 1
Age (years)	−0.170	−0.139	−0.158
Have childrena	−0.003	0.007	0.072
Employment before doctoral enrollmentb	0.008	−0.046	−0.055
Clinical doctoral studentsc	0.107	0.078	0.099
Grade
Second year vs first year	0.007	0.015	−0.003
Third year vs first year	0.011	0.009	−0.024
Fourth year or above vs first year	0.129*	0.142*	0.125*
Frequency of meeting mentor
At least once a month vs at least once a week	0.163**	0.150**	0.147**
Seldom vs at least once a week	0.091	0.060	0.018
Difficulty in publishing doctoral qualification paper
Some effort vs a little bit of effort	0.128	0.115	0.072
A lot of effort vs a little bit of effort	0.314***	0.258**	0.247**
Difficulty in balancing work–family–doctoral program
Some vs almost none	0.151*	0.128*	0.107
Great vs almost none	0.288***	0.260***	0.225**
Step 2
RSES		−0.242***	−0.170**
Step 3
AWAI-S			−0.246***
F	5.262***	6.614***	7.940***
Adjusted R^2	0.148	0.198	0.247
∆R^2	0.183***	0.050***	0.049***

Notes:

a 1, Have no children; 2, have one or more children.

b 1, Not employed before doctoral enrollment; 2, employed before doctoral enrollment.

c 1, Not clinical doctoral students; 2, clinical doctoral students. Grade, doctoral grade.

* P<0.05 (two-tailed);

** P<0.01 (two-tailed);

*** P<0.001 (two-tailed).

Abbreviation: GAD, Generalized Anxiety Disorder.

Figure 1 Theoretical model through which mentoring relationship mediates association between research self-efficacy and depression/anxiety.

Notes: c, Association between research ^a elf-efficacy and depression/anxiety; a, association between research self-efficacy and mentoring relationship; b, association between mentoring relationship and depression/anxiety; c’, association between research self-efficacy and depression/anxiety after adding mentoring relationship as a mediator. *P<0.05; **P<0.01; ***P<0.001.

Table 7 Bootstrapping test of indirect effect of mentoring relationship acting as mediator on association between research self-efficacy and depression/anxiety

Model	Y	c	a	b	c′	a×b (BCa 95% CI)
1	PHQ-9	−0.2065***	0.2993***	−0.2598***	−0.1288*	−0.0778 (−0.1315 to −0.0388)
2	GAD-7	−0.2439***	0.2993***	−0.2424***	−0.1713**	−0.0725 (−0.1227 to −0.0353)

Notes: a×b, indirect effect of research self-efficacy on depression/anxiety via mediator mentoring relationship; c, association between research self-efficacy and depression/anxiety; a, association between research self-efficacy and mentoring relationship; b, association between mentoring relationship and depression/anxiety; c’, association between research self-efficacy and depression/anxiety after adding mentoring relationship as mediator.

* P<0.05;

** P<0.01;

*** P<0.001.

Abbreviations: BC_a, bias-corrected and accelerated; GAD, Generalized Anxiety Disorder; PHQ, Patient Health Questionnaire.