| アブストラクト | BACKGROUND: Smartphone-based cognitive behavioral therapy (CBT) programs offer accessible interventions for subthreshold depression, yet engagement needed for meaningful benefit remains unclear. We examined how lesson and worksheet engagement relate to depressive symptom improvements in a behavioral activation (BA) intervention, accounting for time-varying confounders. METHODS: This secondary analysis included 298 adults assigned to the BA arm of the RESiLIENT trial, a randomized controlled trial in Japan. Lesson and worksheet completion were treated as time-varying exposures, each yielding four engagement patterns: minimal (Few-Few), early (Many-Few), late (Few-Many), and consistently high (Many-Many). Outcomes were depressive symptom changes measured by the Patient Health Questionnaire-9 (PHQ-9) at weeks 6 and 26. We applied the parametric g-formula to estimate counterfactual PHQ-9 changes under each pattern, adjusting for baseline and time-varying confounders. RESULTS: Early lesson engagement during weeks 0-3 was associated with larger PHQ-9 reductions at both weeks 6 and 26, even when later engagement declined (Many-Few vs. week 6: -1.47 [95% CI -2.52 to -0.53]; week 26: -1.27 [-2.53 to -0.17]). In contrast, higher worksheet engagement was linked to improved PHQ-9 at week 6, with maximal benefit among consistently high engagers (Many-Many vs. -1.25 [-2.17 to -0.44]) and late engagers (Few-Many vs. -1.18 [-2.20 to -0.08]), but not persist to week 26. CONCLUSIONS: Greater engagement with smartphone-delivered BA is associated with larger symptom reductions. Early lesson engagement drives sustained benefit, whereas worksheet engagement did not persist. These findings may guide digital CBT design by emphasizing early lesson completion alongside concurrent skill practice. |
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| ジャーナル名 | Psychological medicine |
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| Pubmed追加日 | 2026/5/13 |
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| 投稿者 | Luo, Yan; Inoue, Kosuke; Tajika, Aran; Toyomoto, Rie; Sakata, Masatsugu; Akechi, Tatsuo; Horikoshi, Masaru; Noma, Hisashi; Furukawa, Toshi A |
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| 組織名 | Department of Next-Generation Organ Transplantation, https://ror.org/057zh3y96The;University of Tokyo Graduate School of Medicine Faculty of Medicine, Japan.;Center for Medical Education and Internationalization,;https://ror.org/02kpeqv85Kyoto University Graduate School of Medicine Faculty of;Medicine, Japan.;Department of Health Promotion and Behavioral Sciences,;https://ror.org/04wn7wc95Kyoto University Graduate School of Medicine Faculty of;Department of Neurodevelopmental Medicine, https://ror.org/04wn7wc95Nagoya City;University Graduate School of Medical Sciences and Medical School, Japan.;International Institute for Integrative Sleep Medicine (WPI-IIIS),;https://ror.org/04bcbax71Tsukuba Institute for Advanced Research (TIAR),;University of Tsukuba, Japan.;Department of Psychiatry and Cognitive-Behavioral Medicine,;https://ror.org/04wn7wc95Nagoya City University Graduate School of Medical;Sciences and Medical School, Japan.;Department of Human Sciences, https://ror.org/04bcbax71Musashino University,;Japan.;Department of Interdisciplinary Statistical Mathematics,;https://ror.org/03jcejr58Institute of Statistical Mathematics, Japan.;Office of Institutional Advancement and Communications,;https://ror.org/02kpeqv85Kyoto University, Japan. |
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| Pubmed リンク | https://www.ncbi.nlm.nih.gov/pubmed/42124392/ |
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