A Comprehensive Review and a Meta-Analysis of the Effectiveness of Internet-Based Psychotherapeutic Interventions

ABSTRACT

Internet-based psychotherapeutic interventions have been used for more than a decade, but no comprehensive review and no extensive meta-analysis of their effectiveness have been conducted. We have collected all of the empirical articles published up to March 2006 (n = 64) that examine the effectiveness of online therapy of different forms and performed a meta-analysis of all the studies reported in them (n = 92). These studies involved a total of 9,764 clients who were treated through various Internet-based psychological interventions for a variety of problems, whose effectiveness was assessed by different types of measures. The overall mean weighted effect size was found to be 0.53 (medium effect), which is quite similar to the average effect size of traditional, face-to-face therapy. Next, we examined interacting effects of various possible relevant moderators of the effects of online therapy, including type of therapy (self-help web-based therapy versus online communication-based etherapy), type of outcome measure, time of measurement of outcome (post-therapy or follow-up), type of problem treated, therapeutic approach, and communication modality, among others. A comparison between face-to-face and Internet intervention as reported on in 14 of the studies revealed no differences in effectiveness. The findings of this meta-analysis, and review of additional Internet therapy studies not included in the meta-analysis, provide strong support for the adoption of online psychological interventions as a legitimate therapeutic activity and suggest several insights in regard to its application. Limitations of the findings and recommendations concerning Internet-based therapy and future research are discussed.

KEYWORDS:

• Internet
• Internet intervention
• meta-analysis
• online therapy
• psychotherapy

Notes

Note: ES = effect size; CBT = cognitive-behavior therapy; PE = psychoeducation; FTF = face-to-face; RCT = randomized controlled trial; SR = self-report; TG = treatment group; CG = control group; WL = waiting list; NT = no treatment. N = number of participants receiving online treatment in the statistical analyses.

¹ ES = average of effects of outcome measures used in each study.

Note: ES = effect size; n = number of effects; N = number of participants. Number of effects exceeds 92; some of the studies used more than one type of measure.

Note: ES = effect size; n = number of effects; N = number of participants; PTSD = post-traumatic stress disorder

Note: ES = effect size; n = number of effects; N = number of participants.

Note: ES = effect size; n = number of effects; N = number of participants.

Note: d = effect size; n = number of effects; N = number of participants.

Note: ES = effect size; n = number of effects; N = number of participants.

We are indebted to Ronnen Fluss for his assistance in analyzing the data.

Additional information

Notes on contributors

Azy Barak

Azy Barak, Faculty of Education, University of Haifa, Aba Hushi Rd., Mount Carmel, Haifa, Israel

Liat Hen

Liat Hen, Faculty of Education, University of Haifa, Aba Hushi Rd., Mount Carmel, Haifa, Israel

Meyran Boniel-Nissim

Meyran Boniel-Nissim, Faculty of Education, University of Haifa, Aba Hushi Rd., Mount Carmel, Haifa, Israel

Na'ama Shapira

Na'ama Shapira, Faculty of Education, University of Haifa, Aba Hushi Rd., Mount Carmel, Haifa, Israel