Efficacy and effectiveness of online cognitive behavioral treatment: a decade of Interapy research

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Date: Summer 2011
Publisher: Virtual Reality Medical Institute
Document Type: Report
Length: 1,117 words
Lexile Measure: 1340L

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Since 1996, researchers of the Interapy research group of the University of Amsterdam have been examining the effects of online cognitive behavioral treatment (online CBT). Over the years, the group has conducted nine controlled trials of online CBT of a variety of mental health disorders, among a total of 840 participants. These studies suggest that online CBT is a viable and effective alternative to face-to-face treatment. Treatment adherence was 82%, and reductions in psychopathology represented a large between-group effect size of SMD = 0.9 (95% CI: 0.7 to 1.1), which were maintained over long periods. The research culminated in the foundation of the Interapy clinic, which received Dutch health regulatory body approval in 2005. Since then, costs of online CBT are reimbursed through public health insurance. A large study of treatment outcome of 1,500 patients of the Interapy clinic showed that effects in clinical practice are similar to those observed in the controlled trials, and comparable to selected benchmarks of naturalistic studies of face-to-face CBT. The accumulated evidence provides compelling support for the efficacy and effectiveness of online CBT.

Keywords: Cognitive Behavior Therapy, Internet, Computer Assisted Protocol Directed Therapy, Effectiveness Studies, Internet Intervention, Randomized Controlled Trial

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In 1996, researchers of the University of Amsterdam conducted a small feasibility study of Internet-based psychotherapy. Although the World Wide Web was still in its infancy at that time, they created a website through which they treated 20 students with posttraumatic stress. To the surprise of the research team, the results of what they called "Interapy" were very encouraging. Despite the lack of face-to-face contact, stress symptoms of 19 of the 20 students had reduced to normal levels after treatment. This study was seminal. It was followed by over a decade of research which resulted in full integration of Internet-based treatment in the Dutch public health system. In this presentation, we briefly summarize this research from a meta-analytical perspective.


Over the years, online CBT has been evaluated in nine controlled trials, among a total of 840 participants, across a variety of mental health disorders such as depression, posttraumatic stress, bereavement, work-related stress, panic disorder and bulimia nervosa [2-10]. Most studies were randomized controlled trials, in which participants were randomly assigned to the Interapy treatment condition, or to a waiting list control condition. Outcome was assessed through validated self-report measures, such as the Beck Depression Inventory and the Depression Anxiety Stress Scales, which were administered at pretest, posttest and one to three years after treatment. In 2001, the Interapy research team founded the Interapy clinic, with the aim of implementing online CBT in the public health system. In 2008, the team examined treatment outcome of 1,500 consecutive patients of this clinic, to determine the effectiveness of Interapy during routine clinical practice.


In each study, online CBT induced strong reductions in primary and secondary symptom severities, which were maintained in the long term. Despite the lack of face-to-face contact, treatment adherence was good (82% completed the full treatment), and client satisfaction was high. Consistently, effects of online CBT were superior to those of control conditions. Conservative intention-to-treat estimates of the standardized mean difference (SMD) between the groups ranged from SMD = 0.5 to SMD = 1.3, with an overall SMD of 0.9. In the clinical practice study, dropout was 29%, and symptom reductions represented a large pooled (uncontrolled) effect size of SMD = 1.4 (range: 0.7 [less than or equal to] SMD [less than or equal to] 1.9). Among treatment completers, 71% reliably improved and 52% experienced a clinically significant change (i.e., recovery). Symptoms were more severe in the real world sample in comparison to trial participants, but this had no negative impact on the outcome. Benchmarks against RCT data revealed that effects in the clinic were better, because patients of the clinic had more to gain from treatment.


A decade of Interapy research has provided compelling support for the efficacy and effectiveness of online CBT. Research findings identify online CBT as a viable alternative to current treatment options. Despite the lack of face-to-face contact, treatment adherence is high, effects are comparable to those of face-to-face treatment, and method and outcome generalize well to routine clinical practice. Dutch regulatory health bodies have recognized the potential of online CBT. In 2005, these bodies endorsed the services of the Interapy clinic as a valid alternative to regular, face-to-face treatment. Since then, costs of online treatment are reimbursed through public health insurance to all Dutch citizens with a GP-referral for psychotherapy. The implementation and dissemination of online treatment has started.


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Jeroen Ruwaard (a), (1), Alfred Lange (a), Bart Schrieken (b) and Paul Emmelkamp (a)

(a) University of Amsterdam, Department of Psychology, Amsterdam, the Netherlands

(b) Interapy PLC, Amsterdam, the Netherlands

(1) Corresponding author:

Jeroen Ruwaard

Interapy PLC, P.O. Box 3884

1001 AR Amsterdam

The Netherlands

E-mail: research@interapy.nl

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Gale Document Number: GALE|A260138328