Means and SDs for the ITT sample (iSMI: n=59; AC: n=58) at pretreatment (T1) and post-treatment (T2), and 6 months follow-up (T3)
| Outcome | T1 | T2* | T3* | |||||||||
| iSMI | AC | iSMI | AC | iSMI | AC | |||||||
| M | SD | M | SD | M | SD | M | SD | M | SD | M | SD | |
| Primary outcome | ||||||||||||
| PSS-14 (0–56) | 33.22 | 5.27 | 33.09 | 5.34 | 24.39 | 5.95 | 29.11 | 6.70 | 22.52 | 7.22 | 26.61 | 6.80 |
| Mental health | ||||||||||||
| SMBQ (1–7) | 4.47 | 0.88 | 4.46 | 0.77 | 3.27 | 0.95 | 4.16 | 0.94 | 3.42 | 1.16 | 3.87 | 1.18 |
| Physical fatigue | 4.25 | 0.96 | 4.23 | 0.96 | 3.22 | 1.08 | 3.87 | 1.12 | 3.22 | 1.31 | 3.61 | 1.27 |
| Cognitive weariness | 4.61 | 1.06 | 4.53 | 0.98 | 3.88 | 1.23 | 4.28 | 1.21 | 3.67 | 1.25 | 3.76 | 1.12 |
| Tension | 5.04 | 1.07 | 4.91 | 0.85 | 4.11 | 1.24 | 4.53 | 1.09 | 3.87 | 1.27 | 4.27 | 1.28 |
| Listlessness | 4.28 | 1.35 | 4.44 | 1.20 | 3.31 | 1.43 | 4.06 | 1.22 | 3.05 | 1.42 | 3.77 | 1.50 |
| MADRS-S (0–54) | 15.71 | 6.35 | 15.76 | 4.99 | 9.49 | 5.11 | 14.64 | 6.78 | 10.64 | 7.17 | 12.59 | 6.57 |
| ISI (0–28) | 11.97 | 4.87 | 11.10 | 5.54 | 8.26 | 4.78 | 9.95 | 5.04 | 8.37 | 4.37 | 10.35 | 5.84 |
| Work related | ||||||||||||
| WEMS (32–192)† | 123.66 | 20.41 | 124.47 | 18.89 | 136.68 | 19.56 | 124.61 | 21.45 | 128.60 | 23.12 | 126.20 | 21.12 |
| Supportive work conditions (1–6)† | 4.02 | 0.83 | 4.04 | 0.71 | 4.38 | 0.75 | 4.15 | 0.79 | 4.23 | 0.95 | 4.27 | 0.79 |
| Internal work experience (1–6)† | 4.76 | 0.78 | 4.71 | 0.88 | 4.98 | 0.74 | 4.68 | 0.90 | 4.84 | 0.93 | 4.80 | 0.94 |
| Autonomy (1–6)† | 4.03 | 1.06 | 4.02 | 0.94 | 4.19 | 1.07 | 4.30 | 0.80 | 4.18 | 0.88 | 4.26 | 0.70 |
| Time experience (1–6)† | 2.15 | 1.10 | 2.11 | 1.00 | 2.59 | 1.28 | 2.39 | 1.22 | 2.61 | 1.25 | 2.61 | 1.22 |
| Management (1–6)† | 3.64 | 1.01 | 3.87 | 0.90 | 4.05 | 0.93 | 3.65 | 1.07 | 3.78 | 1.12 | 3.72 | 1.00 |
| Process of change (1–6)† | 3.76 | 1.27 | 3.71 | 1.15 | 4.23 | 1.17 | 3.67 | 1.25 | 3.89 | 1.22 | 3.74 | 1.27 |
| Absenteeism (TiC-P)‡ | 2.00 | 1.15 | 3.81 | 2.98 | 4.43 | 3.69 | 2.70 | 1.95 | 3.50 | 2.32 | 4.25 | 0.96 |
| Presenteeism (TiC-P)‡ | 4.54 | 3.75 | 4.35 | 4.20 | 4.04 | 2.18 | 5.26 | 5.09 | 4.35 | 3.44 | 5.57 | 5.21 |
| AUDIT (0–40) | 3.42 | 2.21 | 3.81 | 2.53 | – | – | – | – | – | – | – | – |
*Missing data imputed by multiple imputation.
†Higher scores indicate better outcomes.
‡In relation to the previous month.
AC, attention control; PSS-14, Perceived Stress Scale; SMBQ, Shirom-Melamed Burnout Questionnaire; MADRS-S, Montgomery Åsberg Depression Rating Scale-self-assessment; ISI, Insomnia Severity Index; ITT, intention to treat; iSMI, internet-based stress management intervention; WEMS, Work Experience Measurement Scale; AUDIT, Alcohol Use Disorders Identification Test; TiC-P, Trimbos and Institute of Medical Technology Assessment Cost Questionnaire for Psychiatry.