Table 3 Pre-test post-test differences of insomnia severity and mental health outcome measures.

From: Open pilot study of a guided digital self-help intervention targeting sleep and the biological clock in university students using a pre-test post-test design

Measure

N

Pre-test, mean (SD)

Post-test, mean (SD)

p value

Cohen’s d (95% CI)

ISI insomnia severity

39

15.49 (3.80)

10.79 (5.09)*

< 0.001

1.04 (0.57, 1.51)

PHQ-9 depression

35

11.34 (4.79)

8.31 (4.89)*

< 0.001

0.63 (0.14, 1.10)

GAD-7 anxiety

35

8.31 (5.98)

6.40 (4.86)*

0.009

0.35 (− 0.12, 0.82)

WSAS functioning

35

19.29 (7.85)

14.63 (8.76)*

0.003

0.56 (0.08, 1.04)

MHQoL quality of life

35

12.71 (3.41)

13.34 (3.04)

0.067

− 0.19 (− 0.66, 0.28)

MHQoL overall mental wellbeing

35

5.43 (1.99)

5.94 (1.68)

0.059

− 0.28 (− 0.75, 0.19)

MCTQ chronotype (mid-sleep, local time)

14

04:41 (02:10)

05:03 (01:18)

0.508

− 0.20 (− 0.94, 0.55)

MCTQ average sleep duration

33

7 h 27 min (1 h 18 min)

8 h 14 min (64 min)*

0.044

− 0.52 (− 1.00, − 0.04)

MCTQ absolute social jetlag

33

58 min (46 min)

1 h 07 min (49 min)

0.318

− 0.19 (− 0.66, 0.28)

  1. Note. ISI Insomnia Severity Index: 7-item insomnia scale; scores ranging from 0 to 28; higher scores indicate higher insomnia severity. PHQ-9 9-item Patient Health Questionnaire; scores ranging from 0 to 27; higher scores indicate higher depression severity. GAD-7 7-item Generalized Anxiety Disorder scale; scores ranging from 0 to 21; higher scores indicate higher anxiety severity. WSAS 5-item Work and Social Adjustment scale; scores ranging from 0 to 40; higher scores indicate higher impairment in functioning. MHQoL 8-item Mental Health Quality of Life Questionnaire; scores ranging from 0 to 21; higher scores indicate better quality of life. MHQoL Overall mental wellbeing rated on a scale of 1 (worst possible wellbeing) to 10 (best possible wellbeing). MCTQ 17-item Munich Chronotype Questionnaire; self-report sleep measure comparing sleep outcomes on work/study days versus free days. h hours, min minutes, MCTQ chronotype in local time.
  2. *p < 0.05, statistically significant difference to pre-test.
Back to article page