Internet-delivered treatments for depression have proved successful, with supported programs offering the potential for improved adherence and outcomes. Internet interventions are particularly interesting in the context of increasing access to interventions, and delivering interventions population-wide.

Investigate the potential feasibility and effectiveness of an online intervention for depression in the community.

Establish the effectiveness of a supported online delivered cognitive behavioural intervention for symptoms of depression in adults in the community.

The study was a randomized controlled trial of an 8-module internet-delivered cognitive behavioral therapy (iCBT) program for adults with depressive symptoms (n = 96) compared to a waiting-list control group (n = 92). Participants received weekly support from a trained supporter. The primary outcome was depressive symptoms as measured by the Beck Depression Inventory (BDI-II). The program was made available nationwide from an established and recognized charity for depression.

For the treatment group, post-treatment effect sizes reported were large for the primary outcome measure (d = 0.91). The between-group effects were moderate to large and statistically significant for the primary outcomes (d = 0.50) favoring the treatment group. Gains were maintained at 6-month follow-up.

The study has demonstrated the efficacy of the online delivered space from depression treatment. Participants demonstrated reliable and statistically significant changes in symptoms from pre- to post-intervention. The study supports a model for delivering online depression interventions population-wide using trained supporters.

The authors have not supplied their declaration of competing interest.