Are self-managed online interventions for depression effective in improving behavioral activation? A secondary analysis of a cluster-randomized controlled trial

Online interventions can effectively improve depressive symptoms. They often include behavioral activation (BA) techniques, but research on the effects on behavioral activation is scarce. This study aims to examine short- and long-term effects of online interventions on behavioral activation in routine care. This study is a secondary analysis of a pragmatic cluster-randomized controlled trial (@ktiv) with a sample of N = 647 GP patients with mild to moderate depression. The intervention group (IG) received treatment-as-usual (TAU) and adjunct access to an online intervention; the control group (CG) received TAU. BA was assessed in terms of the frequency and enjoyment of pleasant activities at baseline, after six weeks and after six months. Intention-to-treat analyses were performed via multilevel mixed linear regression. The frequency of pleasant activities was significantly higher in the IG than in the CG six months after baseline (t(1406) = 2.25, p = .024). The enjoyment of pleasant activities was significantly higher in the IG than in the CG both six weeks (t(1405) = 2.11, p = .035) and six months after baseline (t(1405) = 3.44, p = .001). Initial depressive symptoms significantly moderated the treatment effect on the enjoyment but not the frequency of pleasant activities. BA measures have not been validated in a clinical context. GP patients with mild to moderate depressive symptoms profited from access to an online adjunct intervention in terms of improved behavioral activation. The findings emphasize the usefulness of online interventions as supportive options in mental health care. •Online interventions for depression can support GP care.•Self-managed online interventions can help improve behavioral activation.•Frequency and enjoyment of activities vary over time.•Long-term effects of online interventions on behavioral activation can be observed.