Internet-based cognitive behaviour therapy for symptoms of depression and anxiety: a meta-analysis

V. Spek, P. Cuijpers, I. Nyklicek, H. Riper, J. Keyzer, V. Pop

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Background: We studied to what extent internet-based cognitive behaviour therapy (CBT) programs for symptoms of depression and anxiety are effective. Method: A meta-analysis of 12 randomized controlled trials. Results: The effects of internet-based CBT were compared to control conditions in 13 contrast groups with a total number of 2334 participants. A meta-analysis on treatment contrasts resulted in a moderate to large mean effect size [fixed effects analysis (FEA) d=0.40, mixed effects analysis (MEA) d=0.60] and significant heterogeneity. Therefore, two sets of post hoc subgroup analyses were carried out. Analyses on the type of symptoms revealed that interventions for symptoms of depression had a small mean effect size (FEA d=0.27, MEA d=0.32) and significant heterogeneity. Further analyses showed that one study could be regarded as an outlier. Analyses without this study showed a small mean effect size and moderate, non-significant heterogeneity. Interventions for anxiety had a large mean effect size (FEA and MEA d=0.96) and very low heterogeneity. When examining the second set of subgroups, based on therapist assistance, no significant heterogeneity was found. Interventions with therapist support (n=5) had a large mean effect size, while interventions without therapist support (n=6) had a small mean effect size (FEA d=0.24, MEA d=0.26). Conclusions: In general, effect sizes of internet-based interventions for symptoms of anxiety were larger than effect sizes for depressive symptoms; however, this might be explained by differences in the amount of therapist support. © 2006 Cambridge University Press.
Original languageEnglish
Pages (from-to)319-328
Number of pages10
JournalPsychological Medicine
Issue number3
Early online date20 Nov 2006
Publication statusPublished - Mar 2007

Bibliographical note

Working title: Internet-based cognitive behavior therapy for mood and anxiety disorders: a meta-analysis


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