Effects of an internet-based cognitive behavioral therapy (iCBT) intervention on preventing major depressive episode among workers: a large scale randomized controlled trial

INTERVENTION: A weekly, 6‐session internet learning program which provides psychoeducation of stress management based on cognitive‐behavioral technique. Treatment as usual through the in‐house Employees Assistance Program Monthly e‐mail contact to provide non‐CBT stress management tips CONDITION: Subthreshold depression, depressive episode PRIMARY OUTCOME: 1) Duration before the onset of major depressive episode measured by the web‐based self‐rated CIDI after randomization until 6 and 12 month follow‐up SECONDARY OUTCOME: 1) Severity of subthresholddepression measured by BDI‐II; 2) Severity of depression measured by K6 ; 3) Work performance measured by WHO Health and Performance Questionnaire (HPQ) ; 4) Sick leave days in the past 3 months ; 5) Work Engagement measured by Utrecht Work Engagement Scale (UWES‐9) ; 6)time preference; 7) QOL measured by EQ‐5D; 8)Original questions INCLUSION CRITERIA: 1) Age 20‐60 at study entry 2) Men and women 3) Currently employed full‐time by the business company 4) Can access the Internet via a PC at home or at workplace