Long-term effects of internet-based cognitive behavioral therapy on depression prevention among university students: a randomized controlled factorial trial. (Preprint)

Abstract

Internet-based cognitive-behavioral therapy (iCBT) shows promise in the prevention of depression. However, the specific iCBT components that contribute to its effectiveness remain unclear.

To evaluate the effects of iCBT components in preventing depression among university students.

Using a smartphone CBT app, we randomly allocated university students to the presence or absence of five different iCBT components: self-monitoring (SM), behavioral activation (BA), cognitive restructuring (CR), assertiveness training (AT), and problem-solving (PS). The active intervention lasted eight weeks but the app remained accessible through the follow-up. The primary outcome was the onset of a major depressive episode (MDE) between baseline and 52 weeks follow-up, as assessed with the computerized WHO Composite International Diagnostic Interview (CIDI). Secondary outcomes included changes in the Patient Health Questionnaire-9 (PHQ-9), General Anxiety Disorder-7 (GAD-7), and CBT Skills Scale.

During the 12-month follow-up, 133 of 1301 participants (10.2%) reported onset of MDE. There were no significant differences in the incidence of MDE between the groups with or without each component (Hazard ratios ranged from 0.85 [95% confidence interval: 0.60-1.20] for AT to 1.26 [0.88-1.79] for SM). Furthermore, there were no significant differences in the changes on the PHQ-9, GAD-7 or for CBT Skills Scale between component allocation groups. However, significant reductions in depression and anxiety symptoms were observed among all participants at the 52-week follow-up.

In this study, all participants with and without intervention of iCBT components demonstrated significant improvements in depressive and anxiety symptoms and we could not identify any specific iCBT components that were effective in preventing depression or the acquisition of CBT skills over the 12-month follow-up period. Further research is needed to explore the potential impact of frequency of psychological assessments, non-specific intervention effects, natural change in the mental state, and the baseline depression level.

UMINCTR-000031307

RR2-10.1186/s13063-018-2719-z