Therapeutic processes in digital interventions for anxiety: A systematic review and meta-analytic structural equation modeling of randomized controlled trials

Matthias Domhardt; Hannah Nowak; Sophie Engler; Amit Baumel; Simon Grund; Axel Mayer; Yannik Terhorst; Harald Baumeister

doi:10.1016/j.cpr.2021.102084

Therapeutic processes in digital interventions for anxiety: A systematic review and meta-analytic structural equation modeling of randomized controlled trials

Clin Psychol Rev. 2021 Dec:90:102084. doi: 10.1016/j.cpr.2021.102084. Epub 2021 Sep 13.

Authors

Matthias Domhardt¹, Hannah Nowak², Sophie Engler², Amit Baumel³, Simon Grund⁴, Axel Mayer⁵, Yannik Terhorst⁶, Harald Baumeister²

Affiliations

¹ Department of Clinical Psychology and Psychotherapy, Ulm University, Germany. Electronic address: matthias.domhardt@uni-ulm.de.
² Department of Clinical Psychology and Psychotherapy, Ulm University, Germany.
³ Department of Community Mental Health, University of Haifa, Israel.
⁴ IPN - Leibniz Institute for Science and Mathematics Education, Kiel, Germany.
⁵ Department of Psychological Methods and Evaluation, Bielefeld University, Germany.
⁶ Department of Clinical Psychology and Psychotherapy, Ulm University, Germany; Department of Psychological Research Methods, Ulm University, Germany.

PMID: 34610493
DOI: 10.1016/j.cpr.2021.102084

Abstract

While the efficacy of Internet- and mobile-based interventions (IMIs) for treating anxiety disorders is well established, there is no comprehensive overview about the underlying therapeutic processes so far. Thus, this systematic review and meta-analysis evaluated research on mediators and mechanisms of change in IMIs for adult anxiety disorders (PROSPERO: CRD42020185545). A systematic literature search was performed in five databases (i.e., CENTRAL, Embase, MEDLINE, PsycINFO and ClinicalTrials.gov). Two reviewers independently screened studies for inclusion, assessed the risk of bias and adherence to quality criteria for process research. Overall, 26 studies (N = 6042) investigating 64 mediators were included. Samples consisted predominantly of participants with clinically relevant symptoms of generalized anxiety disorder and severe health anxiety, as well as of participants with non-clinically relevant anxiety symptoms. The largest group of examined mediators (45%) were cognitive variables, evincing also the second highest proportion of significance (19/29); followed in numbers by skills (examined: 22%; significant: 10/14) and a wide range of other (19%; 7/12), emotional/affective (11%; 2/7) and behavioral mediators (3%; 1/2). Meta-analytical synthesis of mediators, limited by a small number of eligible studies, was conducted by deploying a two-stage structural equation modeling approach, resulting in a significant indirect effect for negative thinking (k = 3 studies) and non-significant indirect effects for combined cognitive variables, both in clinical (k = 5) and non-clinical samples (k = 3). The findings of this review might further the understanding on presumed change mechanisms in IMIs for anxiety, informing intervention development and the concurrent optimization of outcomes. Furthermore, by reviewing eligible mediation studies, we discuss methodological implications and recommendations for future process research, striving for causally robust findings. Future studies should investigate a broader range of variables as potential mediators, as well as to develop and apply original (digital) process and engagement measures to gather qualitative and high-resolution data on therapeutic processes.

Keywords: Anxiety disorder; Mechanism of change; Mediator; Psychotherapy; Two-stage structural equation modeling; e- and m-Health.

Publication types

Meta-Analysis
Research Support, Non-U.S. Gov't
Review
Systematic Review

MeSH terms

Anxiety Disorders* / therapy
Anxiety* / therapy
Humans
Latent Class Analysis
Psychotherapy
Randomized Controlled Trials as Topic