JMIR Publications

ABSTRACT

Background:

Digital mental health interventions (DMHIs) offer scalable, cost-effective support for mental health but are predominantly developed in WEIRD (Western, Educated, Industrialized, Rich, Democratic) contexts, calling into question their applicability elsewhere. Dropout, attrition, and adherence rates critically influence DMHI impact yet remain poorly characterized in culturally adapted formats.

Objective:

This systematic review aims (a) to synthesize evidence on dropout, attrition, and adherence in culturally adapted DMHIs delivered to non-WEIRD adult populations and (b) to assess the methodological quality of these studies.

Methods:

We searched PsycINFO, PubMed, and ScienceDirect for RCTs published in English between January 2014 and April 2024 that evaluated digitally delivered, culturally adapted mental health interventions in non-WEIRD settings. Screening and data extraction followed PRISMA guidelines, with two authors independently reviewing studies. We extracted dropout, attrition, adherence, adaptation techniques, and clinical outcomes. Methodological quality was appraised using the AXIS tool.

Results:

Out of 184,047 records, 23 RCTs (N = 4,656) across diverse regions met inclusion criteria. Attrition rates varied from 5.3% to 87% (median ≈ 18.4%), dropout rates from 0% to 66% (median ≈ 18.7%), and adherence rates from 26.3% to 100% (median ≈ 71%). Deep, participatory adaptations—including language translation, culturally resonant content, stakeholder involvement, and iterative refinement—were consistently associated with lower dropout (<11%) and higher adherence (>75%), whereas surface-level adaptations (e.g., translation only) showed higher dropout (up to 56%). Studies combining cultural tailoring with human support reported the most favorable retention and clinical outcomes (e.g., significant reductions in insomnia, depression, anxiety). Methodological quality was high (91% rated “Good”), though some studies lacked representative sampling, objective engagement metrics, and blinded outcome assessment.

Conclusions:

Comprehensive, participatory cultural adaptation promotes engagement and enhances DMHI effectiveness in non-WEIRD populations. Future research should integrate hybrid human-digital models, objective usage metrics, blinded assessments, and larger multi-centre trials to validate and generalize findings. These recommendations will guide the design of culturally responsive DMHIs to maximize public health impact globally. Clinical Trial: PROSPERO CRD42025641863; Available from https://www.crd.york.ac.uk/PROSPERO/view/CRD42025641863.