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),…