Self-guided internet-based cognitive-behavioral therapy interventions exhibit long-term effectiveness for symptomatic control of depression in adults.

A systematic review and meta-analysis of randomized controlled trials (RCTs) aimed to examine the long-term efficacy of self-help internet-based cognitive behavioral therapy (iCBT) programs for people dealing with depression.

The search for both published and unpublished RCTs assessing the extended or follow-up effectiveness of computer-based or iCBT self-help interventions for depression, requiring minimal guidance of no more than 10 minutes per week, was conducted using various sources. These sources included the grey literature, Cochrane Collaboration Depression, Anxiety, and Neurosis Controlled Trials Register (CCDANCTR), correspondence, and reference lists.

The primary outcome of the study was to evaluate the enduring effectiveness of iCBT treatments in contrast to control conditions. Furthermore, the extent to which iCBT treatments maintained their efficacy over an extended period was investigated. The research also featured subgroup analyses focusing on different follow-up timeframes for each outcome measurement. Lastly, whether individuals who underwent iCBT interventions experienced sustained enhancements in their quality of life was also explored.

After conducting the search, 2809 study abstracts were screened. Among them, 15 studies (comprising 17 samples) satisfied all the inclusion criteria and were subsequently included in the analysis for the long-term assessment. The findings revealed that across all follow-up time points, the treatment conditions demonstrated better depression outcomes compared to the control conditions, displaying a medium effect size of 0.43. This effect size was based on data from 1,689 volunteers in 9 RCTs and was represented as a standardized mean difference (SMD) of -0.43.

When examining the long-term effectiveness of iCBT treatment, it was observed that the outcomes at follow-up within the treatment groups were more favorable compared to the post-treatment results. This improvement was associated with a modest effect size of 0.20, based on data from 2,196 participants across 17 RCTs, expressed as an SMD of 0.20.

Additionally, the results concerning the enhancement of the quality of life indicated that the iCBT conditions were more beneficial than the control conditions, showing a slight effect size of 0.19. This finding was derived from 1,345 participants in 3 RCTs and was also represented as an SMD of 0.19.

Self-guided iCBT interventions demonstrated better long-term effectiveness in mitigating depressive symptoms when compared to control groups. Additionally, when examining the iCBT treatment conditions within the same group, clinically meaningful enhancements in alleviating depressive symptoms were observed at follow-up in comparison with the initial post-treatment measurements.