The effectiveness of Internet-delivered treatment for generalized anxiety disorder: An updated systematic review and meta-analysis.

BACKGROUND Generalized anxiety disorder (GAD) is a highly prevalent, chronic disorder associated with impaired quality of life, societal burden, and poor treatment rates. Internet-delivered interventions may improve the accessibility of treatments and are increasingly being used. This study aimed to update a previous meta-analysis to determine the effectiveness of available Internet-delivered interventions in treating symptoms of GAD. METHOD Systematic literature searches were conducted (through April 2020) using Embase, PubMed, PsychINFO, and Cochrane to find randomized controlled trials of Internet-delivered interventions for GAD. Risk of bias was evaluated, and Hedge's g was calculated at posttreatment and follow-up. RESULTS Twenty studies met eligibility criteria and were included in the meta-analysis. Random-effect models detected large effect sizes for primary outcomes of anxiety (g = 0.79) and worry (g = 0.75), favoring treatment. Effect sizes for depression, functional impairment, and quality of life were moderate to large. Maintenance of effects at follow-up seems likely. CONCLUSIONS Results support the effectiveness of Internet-delivered treatments for GAD. Considerable heterogeneity between studies appeared moderated by variability in the interventions themselves, highlighting the importance of further investigation into the characteristics that may optimize treatment outcomes. Overall, Internet-delivery appears to be a viable mode of treatment for GAD with potential to relieve existing gaps in the provision of treatment.