Markus B.T. Nyström, Andreas Stenling, Emma Sjöström, Gregory Neely, Philip Lindner, Peter Hassmén, Gerhard Andersson, Christopher Martell, Per Carlbring

A major problem today is that only about fifty percent of those affected by depression seeks help. One way to reach more sufferers would be by offering easily accessible internet based treatments. The purpose of this study was to compare/evaluate four therapist supported internet administered treatments. Two hundred eighty six participants were included. The treatment period lasted twelve weeks, consisting of the following treatments: 1) physical activity without treatment rational, 2) physical activity with treatment rational, 3) behavioral activation without treatment rational and 4) behavioral activation with treatment rational. All groups (including a control-group) showed a significant decrease in depressive symptoms. When the treatment groups were pooled and compared to the control group, there were significant differences from pretest to posttest (Hedges gav treatment =1.01, control group =0.47). This held true also when each of the four treatment groups was compared to the control group, with one exception: Physical activity without treatment rationale. The differences between how many modules the participants completed could indicate that there are other factors than the treatments that caused the symptom reduction, however, the dose-response analysis did not detect any significant differences on account of modules completed. The results support the positive effects of internet administered treatments for depression, and highlights the importance of psychoeducation, which tends to affect both the treatment outcome and the probability of remaining in treatment. These aspects need to be considered when developing and conducting new treatments for depression, since they would increase the likelihood of positive treatment outcomes.