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

Published online by Cambridge University Press:  20 November 2006

VIOLA SPEK
Affiliation:
Department of Psychology and Health, Tilburg University, The Netherlands Diagnostic Centre Eindhoven, The Netherlands
PIM CUIJPERS
Affiliation:
Department of Clinical Psychology, Vrije Universiteit Amsterdam, The Netherlands
IVAN NYKLÍČEK
Affiliation:
Department of Psychology and Health, Tilburg University, The Netherlands
HELEEN RIPER
Affiliation:
Trimbos-instituut, Netherlands Institute of Mental Health and Addiction, The Netherlands
JULES KEYZER
Affiliation:
Diagnostic Centre Eindhoven, The Netherlands
VICTOR POP
Affiliation:
Department of Psychology and Health, Tilburg University, The Netherlands Diagnostic Centre Eindhoven, The Netherlands

Abstract

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.

Type
Review Article
Copyright
2006 Cambridge University Press

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