Depression and anxiety are major public health problems. This study evaluated the effects of internet-delivered transdiagnostic psychological treatments for individuals with depression, anxiety, or both.

Systematic review with meta-analysis.

Medline (Ovid), Cochrane Library (Wiley), the Web of Science Core Collection (Clarivate), and PsycInfo (EBSCO) were searched on 24 May 2021, with an update on 6 February 2023.

Randomised controlled trials of internet-delivered transdiagnostic psychological treatments, open to both participants with primary depression and participants with primary anxiety. This review concerned all treatment frameworks, both guided and unguided formats and all age groups.

In random-effects meta-analysis, we estimated pooled effects on depression symptoms and anxiety in terms of Hedges’ g with 95% CIs. Absolute and relative heterogeneity was quantified as the ² and I ².

We included 57 trials with 21 795 participants. Nine trials (16%) recruited exclusively from routine care, and three (5%) delivered treatment via video. For adults, large within-group reductions were seen in depression (g=0.90; 95% CI 0.81 to 0.99) and anxiety (g=0.87; 95% CI 0.78 to 0.96). Compared with rudimentary passive controls, the added effects were moderate (depression: g=0.52; 95% CI 0.42 to 0.63; anxiety: g=0.45; 95% CI 0.34 to 0.56) and larger in trials that required all participants to meet full diagnostic criteria for depression or an anxiety disorder. Compared with attention/engagement controls, the added effects were small (depression: g=0.30; 95% CI 0.07 to 0.53; anxiety: g=0.21; 95% CI 0.01 to 0.42). Heterogeneity was substantial, and the certainty of the evidence was very low. Two trials concerned adolescents and reported mixed results. One trial concerned older adults and reported promising results.

Internet-delivered transdiagnostic treatments for depression and anxiety show small-to-moderate added effects, varying by control condition. Research is needed regarding routine care, the video format, children and adolescents and older adults.

CRD42021243172.

In routine psychiatric care in Stockholm, Sweden, a comprehensive therapist-guided intervention for clinically significant health anxiety is implemented. However, there is a need for more easily accessible self-care interventions to improve treatment dissemination. This study aimed to transform an existing therapist-guided digital intervention into a self-care intervention, reducing patient burden and used clinical resources while maintaining quality and safety.

An uncontrolled feasibility study.

Conducted at Karolinska Institutet, a medical university in Sweden, with nationwide recruitment trough online advertisements.

Twenty-five adults used the self-care intervention and underwent telephone assessments, along with completing self-rated questionnaires.

The newly developed 8-week self-care intervention was designed to be user-friendly without therapist guidance, and to facilitate high levels of behavioural engagement.

Indicators of quality and safety, including changes in health anxiety severity (primary), clinician time, participant adherence, perceived credibility/satisfaction with the intervention and adverse events, were benchmarked against a previous study of the more comprehensive intervention it was based on.

Compared with the original guided intervention, the self-care intervention was condensed in terms of text (up to 70% less reading), duration (8 weeks instead of 12) and number of exercises. Quality indicators were similar to the original version. Most participants worked actively with core components in the self-care intervention. Within-group effects on health anxiety from pretreatment to the 3-month follow-up were large (g=1.37; 95% CI 0.74 to 2.00). No serious adverse events were reported.

This brief digital self-care intervention shows potential for increasing access to treatment for individuals with health anxiety while reducing the burden on patients and clinical resources. Future studies should investigate the optimal type of intervention and support for different individuals, and if non-inferiority can be established.

NCT05446766.