Background
Methods
Population
The cohort
Data collection
Measures
Questionnaire items | Response options (coding; distribution at T1, i.e., age 16) | Inclusion in |
---|---|---|
AS = Anxiety Symptoms | ||
DS = Depressive Symptoms | ||
FSS = Functional Somatic Symptoms | ||
Have you have experienced any nervous problems in the past 12 months? | ||
Restlessness | Ticked box (1*; 15.9 %) Unticked box (0*; 84.1 %) | AS |
Concentration difficulties | Ticked box (1*; 15.9 %) Unticked box (0*; 84.1 %) | AS, DS |
Worried or anxious | Ticked box (1*; 12.1 %) Unticked box (0*; 87.9 %) | AS |
Palpitations or stomach problems | Ticked box (1*; 6.6 %) Unticked box (0*; 93.4 %) | AS, FSS |
Anxiety or panic | Ticked box (1*; 4.0 %) Unticked box (0*; 96.0 %) | AS |
How often have you experienced any nervous problems during the past 12 months? | Never (*1; 72.7 %), Off and on (*1; 25.9 %), Quite often (*2; 1.4 %), All the time (*2; 0 %) | |
Does it happen that you feel dejected when you think about the future? | Almost never (0; 31.5 %), No, more seldom (1; 45.7 %), Yes, quite often (1; 20.3 %), Yes, very often (2; 2.5 %) | DS |
How often have you felt sad or depressed during the last 12 months? | Never (0; 27.4 %), Off and on (1; 66.0 %), Quite often (1; 6.2 %), All the time (2; 0.4 %) | DS |
Have you experienced sleeping problems during the last 12 months? | Never (0; 63.1 %), Off and on (1; 33.4 %), Quite often (1; 2.7 %), All the time (2; 0.9 %) | DS, FSS |
Have you now (or have you during the past 12 months had) any of the following diseases or symptoms? | ||
Poor appetite | No (0; 75.8 %), Yes, moderate (1; 22.2 %), Yes, severe (2; 2.0 %) | DS |
Headache, migraine | No (0; 47.0 %), Yes, moderate (1; 48.1 %), Yes, severe (2; 5.0 %) | FSS |
Other stomach ache (than heartburn, gastritis or gastric ulcer) | No (0; 66.3 %), Yes, moderate (1; 32.3 %), Yes, severe (2; 1.4 %) | FSS |
Nausea | No (0; 53.8 %), Yes, moderate (1; 44.6 %), Yes, severe (2; 1.6 %) | FSS |
Backache, hip ache or sciatica | No (0; 74.0 %), Yes, moderate (1; 23.5 %), Yes, severe (2; 2.5 %) | FSS |
Tiredness/fatigue | No (0; 43.8 %), Yes, moderate (1; 50.2 %), Yes, severe (2; 6.0 %) | DS, FSS |
Breathlessness | No (0; 81.9 %), Yes, moderate (1; 16.6 %), Yes, severe (2; 1.5 %) | FSS |
Dizziness | No (0; 80.7 %), Yes, moderate (1; 18.2 %), Yes, severe (2; 1.1 %) | FSS |
Overstrain | No (0; 84.8 %), Yes, moderate (1; 14.3 %), Yes, severe (2; 0.9 %) | FSS |
Anxiety symptoms
Depressive symptoms
Data analysis
Results
Factor structure of the mental health measures
Scale | Wave |
N
|
χ
2
| Df |
P
| CFI | RMSEA | 90 % CI for RMSEA | Range of factor loadings | Cronbach’s alpha |
---|---|---|---|---|---|---|---|---|---|---|
Anxiety symptoms | T1 | 928 | 18.45 | 5 | .002 | .99 | .05 | .03–.08 | .62–.85 | .72 |
T2 | 929 | 48.20 | 5 | <0.001 | .98 | .10 | .07–.12 | .80–.91 | .79 | |
T3 | 914 | 22.42 | 5 | <0.001 | 1.00 | .06 | .04–.09 | .86–.98 | .90 | |
T4 | 929 | 51.46 | 5 | <0.001 | .99 | .10 | .08–.13 | .82–.92 | .86 | |
Depressive symptoms | T1 | 929 | 18.45 | 9 | .030 | .99 | .03 | .01–.06 | .44–.80 | .65 |
T2 | 929 | 5.78 | 9 | .762 | 1.00 | .00 | .00–.03 | .44–.74 | .61 | |
T3 | 921 | 19.66 | 9 | .020 | .99 | .04 | .01–.06 | .55–.79 | .67 | |
T4 | 929 | 34.07 | 9 | <0.001 | .99 | .06 | .04–.08 | .62–.89 | .76 | |
FSS | T1 | 929 | 85.29 | 35 | <0.001 | .97 | .04 | .03–.05 | .43–.67 | .70 |
T2 | 929 | 111.67 | 35 | <0.001 | .95 | .05 | .04–.06 | .47–.68 | .70 | |
T3 | 921 | 101.52 | 35 | <0.001 | .97 | .05 | .04–.06 | .47–.75 | .74 | |
T4 | 929 | 154.35 | 35 | <0.001 | .96 | .06 | .05–.07 | .48–.79 | .79 | |
GHQ6-n | T1 | 926 | 165.42 | 9 | <0.001 | .97 | .14 | .12–.16 | .64–.89 | .81 |
T2 | 927 | 169.88 | 9 | <0.001 | .98 | .14 | .12–.16 | .66–.95 | .83 | |
T3 | 916 | 180.78 | 9 | <0.001 | .99 | .14 | .13–.16 | .62–.97 | .84 | |
T4 | 923 | 235.61 | 9 | <0.001 | .98 | .17 | .15–.18 | .68–.96 | .85 | |
GHQ6-p | T1 | 927 | 53.21 | 9 | .000 | .98 | .07 | .06–.09 | .45–.76 | .72 |
T2 | 927 | 56.44 | 9 | .000 | .98 | .08 | .06–.10 | .45–.79 | .72 | |
T3 | 917 | 92.58 | 9 | .000 | .98 | .10 | .08–.12 | .61–.85 | .79 | |
T4 | 926 | 155.40 | 9 | .000 | .96 | .13 | .12–.15 | .58–.85 | .80 |
Scale | Model |
χ
2
| Df |
p
| CFI | RMSEA | 90 % CI for RMSEA | Range of factor loadings | Comparison | ∆χ2 | ∆df |
P
|
---|---|---|---|---|---|---|---|---|---|---|---|---|
Anxiety symptoms T1–T4 | A | 262.42 | 136 | <0.001 | .99 | .03 | .03–.04 | .68–.96 | ||||
B | 270.60 | 148 | <0.001 | .99 | .03 | .02–.04 | .73–.95 | A vs. B | 21.41 | 12 | .045 | |
Depressive symptoms T1–T4 | A | 264.95 | 210 | .006 | .99 | .02 | .01–.02 | .41–.91 | ||||
B | 290.00 | 225 | .002 | .99 | .02 | .01–.02 | .50–.90 | A vs. B | 24.94 | 15 | .051 | |
FSS T1–T4 | A | 974.82 | 674 | <0.001 | .97 | .02 | .02–.03 | .42–.78 | ||||
B | 978.29 | 701 | <0.001 | .97 | .02 | .02–.02 | .46–.77 | A vs. B | 38.24 | 27 | .074 | |
GHQ6-n T1–T4 | A | 783.86 | 212 | <0.001 | .98 | .05 | .05–.06 | .61–.97 | ||||
B | 753.92 | 227 | <0.001 | .98 | .05 | .05–.05 | .62–.97 | A vs. B | 24.43 | 15 | .058 | |
GHQ6-p T1–T4 | A | 429.71 | 210 | <0.001 | .98 | .03 | .03–.04 | .44–.84 | ||||
B | 480.69 | 225 | <0.001 | .97 | .04 | .03–.04 | .53–.84 | A vs. B | 55.54 | 15 | .000 |
Factorial invariance over time
Combined measures
Model |
N
|
χ
2
| df |
p
| CFI | RMSEA | 90 % CI for RMSEA | Range of factor loadings | Comparison | ∆χ2 | ∆df |
p
| |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
T1 | A | 929 | 242.13 | 116 | <0.001 | .97 | .03 | .03–.04 | .39–.85 | ||||
B | 929 | 316.70 | 118 | <0.001 | .95 | .04 | .04–.05 | .39–.82 | A vs. B | 48.36 | 2 | <0.001 | |
C | 929 | 427.24 | 119 | <0.001 | .92 | .05 | .05–.06 | .33–.81 | B vs. C | 62.14 | 1 | <0.001 | |
T2 | A | 929 | 239.75 | 116 | <0.001 | .98 | .03 | .03–.04 | .42–.90 | ||||
B | 929 | 363.63 | 118 | <0.001 | .95 | .05 | .04–.05 | .41–.87 | A vs. B | 53.43 | 2 | <0.001 | |
C | 929 | 491.39 | 119 | <0.001 | .93 | .06 | .05–.06 | .42–.86 | B vs. C | 59.28 | 1 | <0.001 | |
T3 | A | 921 | 335.01 | 116 | <0.001 | .99 | .05 | .04–.05 | .45–.97 | ||||
B | 921 | 491.34 | 118 | <0.001 | .98 | .06 | .05–.06 | .45–.98 | A vs. B | 71.88 | 2 | <0.001 | |
C | 921 | 635.43 | 119 | <0.001 | .98 | .07 | .06–.07 | .39–.98 | B vs. C | 59.04 | 1 | <0.001 | |
T4 | A | 929 | 439.58 | 116 | <0.001 | .97 | .06 | .05–.06 | .48–.92 | ||||
B | 929 | 485.53 | 118 | <0.001 | .97 | .06 | .05–.06 | .48–.91 | A vs. B | 29.99 | 2 | <0.001 | |
C | 929 | 666.37 | 119 | <0.001 | .95 | .07 | .07–.08 | .42–.90 | B vs. C | 84.05 | 1 | <0.001 |