BACKGROUND
Web-based interventions have been shown to be effective for the treatment of depression. However, interventions are often complex and include a variety of elements, making it difficult to identify the most effective component(s).
OBJECTIVE
The aim of this pilot study was to shed light on mechanisms in the online treatment of depression by comparing a single-module, fully automated intervention for depression (internet-based behavioral activation [iBA]) to a nonoverlapping active control intervention and a nonactive control group.
METHODS
We assessed 104 people with at least mild depressive symptoms (Patient Health Questionnaire-9, >4) via the internet at baseline (t<sub>0</sub>) and 2 weeks (t<sub>1</sub>) and 4 weeks (t<sub>2</sub>) later. After the t<sub>0</sub> assessment, participants were randomly allocated to one of three groups: (1) iBA (n=37), (2) active control using a brief internet-based mindfulness intervention (iMBI, n=32), or (3) care as usual (CAU, n=35). The primary outcome was improvement in depressive symptoms, as measured using the Patient Health Questionnaire-9. Secondary parameters included changes in activity, dysfunctional attitudes, and quality of life
RESULTS
While groups did not differ regarding the change in depression from t<sub>0</sub> to t<sub>1</sub> (η<sub>p</sub><sup>2</sup>=.007, <i>P</i>=.746) or t<sub>0</sub> to t<sub>2</sub> (η<sub>p</sub><sup>2</sup>=.008, <i>P</i>=.735), iBA was associated with a larger decrease in dysfunctional attitudes from t<sub>0</sub> to t<sub>2</sub> in comparison to CAU (η<sub>p</sub><sup>2</sup>=.053, <i>P</i>=.04) and a larger increase in activity from t<sub>0</sub> to t<sub>1</sub> than the pooled control groups (η<sub>p</sub><sup>2</sup>=.060, <i>P</i>=.02). A change in depression from t<sub>0</sub> to t<sub>2</sub> was mediated by a change in activity from t<sub>0</sub> to t<sub>1</sub>. At t<sub>1</sub>, 22% (6/27) of the participants in the iBA group and 12% (3/25) of the participants in the iMBI group indicated that they did not use the intervention.
CONCLUSIONS
Although we did not find support for the short-term efficacy of the single-module iBA regarding depression, long-term effects are still conceivable, potentially initiated by changes in secondary outcomes. Future studies should use a longer intervention and follow-up interval.
CLINICALTRIAL
DKRS (#DRKS00011562)
Cognitive Predictors of Depressive Symptoms: Cognitive Reactivity, Mood Reactivity, and Dysfunctional Attitudes
