Accepted for/Published in: Journal of Medical Internet Research
Date Submitted: Sep 3, 2024
Date Accepted: Apr 15, 2025
Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.
Nationwide implementation of unguided cognitive behavioural therapy for adolescent depression: An observational study of SPARX
ABSTRACT
Background:
Internet-based cognitive behavioural therapy (iCBT) interventions are effective in clinical trials; however, iCBT implementation data are seldom reported.
Objective:
To evaluate uptake, adherence and changes in symptoms of depression for 12–19-year-olds using an unguided pure self-help iCBT intervention (‘SPARX’) during the first seven years of it being publicly available without referral in Aotearoa New Zealand (NZ).
Methods:
SPARX is a seven-module self-help intervention for adolescents with mild to moderate depression. It is freely available to anyone with a NZ Internet Protocol address without referral and is delivered in an unguided ‘serious game’ format. We report uptake, number of modules completed, and changes in depressive symptoms on the Patient Health Questionnaire adapted for Adolescents (PHQ-A), which is embedded at the start of modules 1, 4 and 7 of SPARX.
Results:
In total, 21,320 12–19-year-olds (approximately 2% of 12-19-year-olds in NZ) registered to use SPARX. Of these, 63.6% started SPARX (n=13,564; 62.7% female, 31.4% male and 5.9% another gender identity or gender not specified; 64.4% New Zealand European, 14.3% Māori, 8.9% Asian, 3.7% Pacific, and 8.4% another ethnic identity; mean age 14.9 years). The mean PHQ-A at baseline was 13.6 (SD=7.7) with 16.1% reporting no or minimal symptoms, 37.4% reporting mild to moderate symptoms (i.e., the target group) and 46.7% reporting moderately severe or severe symptoms. Among those who started, 51% completed Module 1; 7% completed at least 4 modules and 3% completed all 7 modules. The effect size for changes in depressive symptoms for those who completed two or more PHQ-A assessments was 0.43 (0.3 8for those who reached the mid-way assessment only and 0.5 1 for those who completed the final/Module 7 assessment).
Conclusions:
SPARX reached a meaningful proportion of the adolescent population. The effect size for those who engaged with it was comparable to trial results. However, completion was low. Key challenges included addressing logistical barriers such as slow download speeds and compatibility with some devices. Ongoing attention to rapidly evolving technologies and engagement are required. Real-world implementation analyses offer important insights for understanding and improving the impact of digital mental health tools and should be routinely reported. Clinical Trial: NA
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