Supplementary Material for: Efficacy and Moderators of Internet-Based Interventions in Adults with Subthreshold Depression: An Individual Participant Data Meta-Analysis of Randomized Controlled Trials

  • J.A. Reins (Contributor)
  • C. Buntrock (Contributor)
  • J. Zimmermann (Contributor)
  • S. Grund (Contributor)
  • M. Harrer (Contributor)
  • D. Lehr (Contributor)
  • H. Baumeister (Contributor)
  • K. Weisel (Contributor)
  • M. Domhardt (Contributor)
  • K. Imamura (Contributor)
  • N. Kawakami (Contributor)
  • V. Spek (Contributor)
  • S. Nobis (Contributor)
  • F. Snoek (Contributor)
  • Pim Cuijpers (Contributor)
  • J.P. Klein (Contributor)
  • S. Moritz (Contributor)
  • D.D. Ebert (Contributor)



Introduction: Evidence on effects of Internet-based interventions to treat subthreshold depression (sD) and prevent the onset of major depression (MDD) is inconsistent. Objective: We conducted an individual participant data meta-analysis to determine differences between intervention and control groups (IG, CG) in depressive symptom severity (DSS), treatment response, close to symptom-free status, symptom deterioration and MDD onset as well as moderators of intervention outcomes. Methods: Randomized controlled trials were identified through systematic searches via PubMed, PsycINFO, Embase and Cochrane Library. Multilevel regression analyses were used to examine efficacy and moderators. Results: Seven trials (2,186 participants) were included. The IG was superior in DSS at all measurement points (posttreatment: 6–12 weeks; Hedges’ g = 0.39 [95% CI: 0.25–0.53]; follow-up 1: 3–6 months; g = 0.30 [95% CI: 0.15–0.45]; follow-up 2: 12 months, g = 0.27 [95% CI: 0.07–0.47], compared with the CG. Significantly more participants in the IG than in the CG reached response and close to symptom-free status at all measurement points. A significant difference in symptom deterioration between the groups was found at the posttreatment assessment and follow-up 2. Incidence rates for MDD onset within 12 months were lower in the IG (19%) than in the CG (26%). Higher initial DSS and older age were identified as moderators of intervention effect on DSS. Conclusions: Our findings provide evidence for Internet-based interventions to be a suitable low-threshold intervention to treat individuals with sD and to reduce the incidence of MDD. This might be particularly true for older people with a substantial symptom burden.
Date made available1 Jan 2020
PublisherUnknown Publisher

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