AbstractThis article presents a research that answers the question whether internet-based treatment is an effective treatment for subthreshold depression in people over fifty years of age. 301 participants with subthreshold depression were randomized to internet-based treatment, group treatment, or a waiting-list. Treatment response was defined as the difference in pre-treatment and post-treatment or follow-up scores on the Beck Depression Inventory. At post-treatment, we found a significant difference between the waiting-list and
the two treatment conditions. The two treatment conditions did not differ significantly. At one-year follow-up, we found no difference between both treatment conditions and a significant difference between the waiting-list and internet-based treatment. It is concluded that internet-based treatment for subthreshold depression is effective.