Characteristics of study participants
We included a total of 587 adults into the study and all of these participants had complete data. A little more than half of the participants were men (51.3%). The mean age of the participants was 35.76 (SD= 13.8), and a quarter were not literate (26.1%). The majority of the participants were married (72.8%) and came from rural areas (69.1%). More than 95% of the participants were Christian. In terms of occupation, 38.7% were farmers and 26.2% were housewives. The main reason for their visit for the majority of the participants (74.1%) was new illness and a little more than a quarter of the participants (26.9%) had ever sought help in the facility or other places for their presenting complaint. See Table 1 for details of the socio-demographic characteristics of the participants.
Table 1: Socio-demographic characteristics of participants (n=587)
Characteristics
|
|
N
|
%
|
Sex
|
Female
|
286
|
48.7
|
|
Male
|
301
|
51.3
|
Age (years)
|
18-24
|
139
|
23.7
|
|
25-34
|
159
|
27.1
|
|
35-44
|
128
|
21.8
|
|
45-64
|
133
|
22.7
|
|
65+
|
28
|
4.8
|
|
|
Mean 35.76
|
SD 13.8
|
Marital status
|
Never married
|
130
|
22.1
|
|
Married
|
427
|
72.7
|
|
Divorced
|
12
|
2.0
|
|
Widowed
|
18
|
3.1
|
Residence
|
Urban
|
182
|
31.0
|
|
Rural
|
405
|
69.0
|
Educational level
|
Cannot read and write
|
154
|
26.2
|
|
Literate, but no formal education
|
77
|
13.1
|
|
Primary school
|
205
|
34.9
|
|
High school or above
|
152
|
25.9
|
Religion
|
Christian
|
559
|
95.2
|
|
Muslim
|
28
|
4.8
|
Occupation
|
Paid work
|
62
|
10.6
|
|
Private work
|
66
|
11.2
|
|
Farming
|
226
|
38.5
|
|
Housewife
|
154
|
26.2
|
|
Student
|
53
|
9.0
|
|
Unemployed
|
10
|
1.7
|
|
Other
|
16
|
2.7
|
Income level or relative wealth
|
Very low
|
48
|
8.2
|
|
Lower
|
195
|
33.2
|
|
Average
|
321
|
54.7
|
|
Higher
|
21
|
3.6
|
|
Very high
|
2
|
0.3
|
Do you have children?
|
No
|
152
|
25.9
|
|
Yes
|
435
|
74.1
|
Number of children (n= 435)
|
1-3 children
|
172
|
39.5
|
|
4-6 children
|
192
|
44.1
|
|
More than 6 children
|
71
|
16.3
|
What is the main reason for your visit today?
|
New illness
|
435
|
74.1
|
|
Acute illness
|
39
|
6.6
|
|
Injury
|
2
|
0.3
|
|
Check-up or other preventive care
|
4
|
0.7
|
|
Prenatal check-up
|
3
|
0.5
|
|
Follow-up appointment for earlier chronic illness
|
94
|
16.0
|
|
Follow-up appointment for earlier accident
|
3
|
0.5
|
|
Other
|
7
|
1.2
|
Have you ever come to this facility or gone to other places for seeking help? (n=584)
|
No
|
427
|
73.1
|
|
Yes
|
157
|
26.9
|
SD= Standard deviation; n= Number of participants
Construct validity
Exploratory factor analysis indicated, with both eigenvalue and scree plot criteria, that the PHQ-9, PHQ-11 and WHO-5 were unidimensional, with the factor in each scale explaining 51.0%, 48.3% and 69.4% of the total variance, respectively. All items in the scales highly loaded onto the resulting factor. The factor loadings for the PHQ-9 ranged from 0.65 to 0.79; for PHQ-11 0.64 to 0.77; and for WHO-5 0.78 to 0.87. See Table 2.
Table 2: Rotated factor loadings of the exploratory factor analysis of PHQ-9, PHQ-11 and WHO-5
Item
|
Factor loading
|
PHQ-9
|
Little interest or pleasure in doing things
|
0.74
|
Feeling down, depressed, or hopeless
|
0.79
|
Sleep problem
|
0.73
|
Feeling tired or having little energy
|
0.70
|
Eating problem
|
0.67
|
Feeling bad about yourself
|
0.74
|
Trouble concentrating
|
0.69
|
Agitation or retardation
|
0.72
|
Thoughts that you would be better off dead
|
0.65
|
PHQ-11
|
Little interest or pleasure in doing things
|
0.72
|
Feeling down, depressed, or hopeless
|
0.77
|
Sleep problem
|
0.74
|
Feeling tired or having little energy
|
0.68
|
Eating problem
|
0.66
|
Feeling bad about yourself
|
0.73
|
Trouble concentrating
|
0.68
|
Agitation or retardation
|
0.69
|
Thoughts that you would be better off dead
|
0.64
|
Irritability
|
0.65
|
Noise intolerance
|
0.65
|
WHO-5
|
Cheerful and good spirit
|
0.86
|
Calm and relaxed
|
0.87
|
Active vigorous
|
0.84
|
Fresh and rested
|
0.78
|
Interest
|
0.81
|
WHO-5= World Health Organization-Five Well-being Index; PHQ= Patient health questionnaire
The PHQ-15 was slightly different as there is a gender specific item (menstrual pain). First a factor analysis including all of the 15 items (PHQ-15a) resulted in three factors with eigenvalue >1. The first factor explained 30.8% and the other two factors explained 7.8% and 7.0% of the total variance. Most of the items clearly loaded onto their respective factors, with factor loadings ranging from 0.49 to 0.75 (Table 3). Two items (dizziness and fainting spells), cross-loaded onto two factors. It was generally very difficult to interpret the three factors as items loaded in each of the factors were mixed.
Factor analysis was performed again with the 13 items (PHQ-15b), excluding the gender specific item (Menstrual cramps or other problems with periods) and another item related to sexual intercourse (Pain or problems during sexual intercourse). The data for PHQ-15b (with the 13 items) seemed to suggest bifactorial structure. The first factor explained 34.1% and the second factor 8.5% of the total variance. Seven items loaded onto the first factor, with factor loadings ranging from 0.42 to 0.71, and six items loaded onto the second factor, with factor loadings from 0.54 to 0.66 (Table 4). There were no items which cross-loaded onto more than one factor. It appeared that items loaded onto the second factor were purely physical (e.g. stomach pain, back pain and problems with bowels); whereas factors loaded onto the first factor were not purely physical although they have physical manifestations (e.g. dizziness, trouble sleeping, tiredness, fainting and shortness of breath).
Internal consistency of items, as evaluated by Cronbach’s alpha, for all the scales was good: 0.87 for PHQ-9, 0.89 for PHQ-11, 0.83 for PHQ-15 and 0.89 for WHO-5. Internal consistency for the PHQ-2 was lower (α= 0.72).
Table 3: Rotated factor loadings of the exploratory factor analysis of PHQ-15a and PHQ-15b
Item
|
Factor loading
|
|
|
PHQ-15a
|
PHQ-15b
|
|
Factor 1
|
Factor 2
|
Factor 3
|
Factor 1
|
Factor 2
|
Stomach pain
|
|
0.69
|
|
|
0.66
|
Back pain
|
|
0.54
|
|
|
0.61
|
Pain in your arms, legs, or joints
|
0.52
|
|
|
|
0.46
|
Menstrual cramps or other problems with periods
|
|
|
0.70
|
|
|
Headaches
|
|
0.60
|
|
|
0.54
|
Chest pain
|
0.57
|
|
|
0.42
|
|
Dizziness
|
|
0.42
|
0.45
|
0.55
|
|
Fainting spells
|
0.48
|
|
0.52
|
0.71
|
|
Heart pound or race
|
0.75
|
|
|
0.69
|
|
Shortness of breath
|
0.70
|
|
|
0.68
|
|
Pain or problems during sexual intercourse
|
0.49
|
|
|
|
|
Constipation, loose bowels
|
|
0.61
|
|
|
0.60
|
Nausea
|
|
0.61
|
|
|
0.64
|
Tired or having low energy
|
0.61
|
|
|
0.64
|
|
Trouble sleeping
|
0.47
|
|
|
0.46
|
|
PHQ-15= Patient health questionnaire-15
Concurrent validity and convergent validity
Scores for all of the depression screening scales were moderately or highly correlated with each other (Rho= 0.58 to 0.98). The scores for PHQ-2, PHQ-9 and PHQ-11 were highly correlated (Rho= 0.85 to 0.98) with each other suggesting one could substitute the other. Scores for all the depression screening scales were moderately correlated with GAD-7 (Rho= 0.55 to 0.73) and WHODAS-2 scores (0.58 to 0.74). Scores for all of the depression screening scales were correlated with scores for social support and list of threatening events; however, the correlations were lower (Rho= 0.21 to 0.42). See Table 5. Differences between psychiatrist depression diagnosed and non-diagnosed cases in the median scores of all the screening scales were statistically significant (P<0.01). The median score for PHQ-2, PHQ-9, PHQ-11, PHQ-15 and WHO-5 in the diagnosed cases were 3, 12, 15, 11 and 6, respectively; whereas in the non-diagnosed cases were 2, 7, 8, 8 and 9, respectively.
Table 4: Inter-correlation of depression screening scales and their correlation with anxiety, disability, social support and list of threatening events
|
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
PHQ-2
|
(1)
|
1.00
|
|
|
|
|
|
|
|
|
PHQ-9
|
(2)
|
0.87
|
1.00
|
|
|
|
|
|
|
|
PHQ-11
|
(3)
|
0.85
|
0.98
|
1.00
|
|
|
|
|
|
|
PHQ-15
|
(4)
|
0.61
|
0.74
|
0.75
|
1.00
|
|
|
|
|
|
WHO-5
|
(5)
|
-0.58
|
-0.69
|
-0.70
|
-0.60
|
1.00
|
|
|
|
|
GAD-7
|
(6)
|
0.63
|
0.71
|
0.73
|
0.64
|
-0.55
|
1.00
|
|
|
|
WHODAS-2.0
|
(7)
|
0.65
|
0.74
|
0.74
|
0.69
|
-0.58
|
0.70
|
1.00
|
|
|
OSSS-3
|
(8)
|
-0.31
|
-0.27
|
-0.27
|
-0.28
|
0.21
|
-0.33
|
-0.37
|
1.00
|
|
LTE
|
(9)
|
0.38
|
0.40
|
0.42
|
0.37
|
-0.34
|
0.43
|
0.41
|
-0.27
|
1.00
|
PHQ= Patient health questionnaire; WHO-5= World Health Organization-Five Well-being Index; GAD-7= seven item generalized anxiety disorder scale; WHODAS= World Health Organization Disability Assessment Schedule; OSSS-3= Oslo social support scale; LTE= List of threatening experiences
Association of ratings of items in screening tools with depression diagnosis
All of the PHQ-9 items were significantly associated with depression diagnosis (Table 5). However, items Feeling down, depressed or hopeless; Sleep problem; Feeling bad about oneself and Suicidal ideation were highly associated compared to the other items. The new items we added into the PHQ-9 (Irritability and Noise intolerance) had higher association than all of the PHQ-9 items, except the item Feeling down, depressed and hopeless. Although most of the PHQ-15 items had statistically significant association with depression diagnosis, the strength of association for most of the items was weak. Nevertheless, four items (Fainting spells, Problems during sexual intercourse, Feeling tired or having low energy and Trouble sleeping) had higher association compared to the other items. Overall, it appeared that items measuring emotional problems were highly associated with depression diagnosis more than items measuring cognitive or somatic symptoms. Particularly, items measuring physical problems had weak association with psychiatrist diagnosis of depression (Table 5). All items in the WHO-5 had negative and statistically significant association with depression diagnosis.
Table 5: Association of items in screening tools with depression diagnosis
Item
|
Odds Ratio (95% CI)
|
P-value
|
PHQ-9+2
|
|
|
Little interest or pleasure in doing things
|
1.30 (1.05, 1.61)
|
<0.05
|
Feeling down, depressed, or hopeless
|
2.46 (1.87, 3.23)
|
<0.01
|
Sleep problem
|
2.03 (1.55, 2.67)
|
<0.01
|
Feeling tired or having little energy
|
1.63 (1.28, 2.08)
|
<0.01
|
Eating problem
|
1.40(1.08, 1.81)
|
<0.01
|
Feeling bad about yourself
|
2.01 (1.56, 2.59)
|
<0.01
|
Trouble concentrating
|
1.97 (1.51, 2.57)
|
<0.01
|
Agitation or retardation
|
1.90 (1.43, 2.51)
|
<0.01
|
Thoughts that you would be better off dead
|
2.04 (1.49, 2.79)
|
<0.01
|
Irritability
|
2.64 (1.47, 4.72)
|
<0.01
|
Noise intolerance
|
2.25 (1.30, 3.91)
|
<0.01
|
PHQ-15
|
|
|
Stomach pain
|
1.53 (1.10, 2.02)
|
<0.05
|
Back pain
|
1.17 (0.85, 1.61)
|
0.339
|
Pain in your arms, legs, or joints
|
1.50 (1.10, 2.05)
|
<0.05
|
Menstrual cramps or other problems with periods
|
1.31 (0.86, 1.99)
|
0.210
|
Headaches
|
1.53 (1.06, 2.20)
|
<0.05
|
Chest pain
|
1.39 (0.96, 2.02)
|
0.079
|
Dizziness
|
1.91 (1.32, 2.75)
|
<0.05
|
Fainting spells
|
2.20 (1.20, 4.04)
|
<0.05
|
heart pound or race
|
1.98 (1.39, 2.84)
|
<0.01
|
Shortness of breath
|
1.86 (1.30, 2.66)
|
<0.01
|
Pain or problems during sexual intercourse
|
2.08 (1.33, 3.24)
|
<0.01
|
Constipation, loose bowels
|
1.17 (0.80, 1.70)
|
0.423
|
Nausea, gas or indigestion
|
1.52 (1.10, 2.12)
|
<0.05
|
Feeling tired or having low energy
|
2.08 (1.41, 3.07)
|
<0.01
|
Trouble sleeping
|
2.26 (1.59, 3.23)
|
<0.01
|
WHO-5
|
|
|
Cheerful and good spirit
|
0.60 (0.48, 0.75)
|
<0.01
|
Calm and relaxed
|
0.56 (0.45, 0.71)
|
<0.01
|
Active vigorous
|
0.52 (0.40, 0.67)
|
<0.01
|
Fresh and rested
|
0.698 (0.58, 0.85)
|
<0.01
|
Interest
|
0.58 (0.45, 0.74)
|
<0.01
|
PHQ= Patient health questionnaire; WHO-5= World Health Organization-Five Well-being Index; CI= Confidence interval