Internet-delivered cognitive behaviour therapy for affective disorders, anxiety disorders and somatic conditions: An updated systematic umbrella review.

Background: Internet-delivered cognitive behaviour therapy (ICBT), which can involve guidance from a clinician, continues to be a way to deliver psychological treatments. A previous umbrella review identified moderate-to-large effect sizes favouring ICBT compared to control conditions when treating major depression and anxiety disorders. Given the rapid developments in the field, an updated umbrella review of available meta-analyses can show other conditions and subpopulations for which ICBT is effective. The aim of the study was to provide an expanded overview of the efficacy of ICBT for a broader range of adult psychiatric and somatic conditions. Methods: We conducted an updated search of the literature since the publication of the previous umbrella review back in 2019 and up until March 2024. Five different search engines were used (Medline (OVID), Scopus, Web of Science, Cochrane library and CINAHL). The search was expanded to include additional psychiatric conditions (e.g., suicidal ideation) and somatic conditions (e.g., tinnitus and chronic pain). Results: Of the 6509 identified articles, 39 meta-analyses met the inclusion criteria. In these meta-analyses 19 unique outcomes were represented. The most common outcome was symptoms of major depressive disorder, followed by symptoms of anxiety. Effect sizes for the comparisons against control conditions ranged between small (e.g., SMD = 0.10 for stress in employees) to large (e.g., SMD = 1.20 for depressive symptoms among older adults). Conclusions: ICBT can generally reduce symptoms of a wide range of conditions including both psychiatric and somatic conditions, as well as other mental health problems. This updated review of available meta-analyses also indicated that ICBT has been successful in treating symptoms in different subpopulations such as older adults and students. However, some knowledge gaps remain, including the use of ICBT for psychotic disorders, and the quality of the available meta-analyses' points to a need for more stringent methodological procedures.