The effects of a sleep-focused smartphone application on insomnia and depressive symptoms: a randomised controlled trial and mediation analysis

Abstract

Background: Rates of depression are increasing among adolescents. A novel way to reduce depression is by improving sleep. We evaluated whether an app-based intervention for insomnia improved sleep and depression, and whether changes in insomnia mediated changes in depression. Methods: We conducted a 2-arm single-blind randomised controlled trial at the Black Dog Institute in Australia. Adolescents 12–16 years experiencing insomnia symptoms were randomly allocated to receive Sleep Ninja, an app-delivered cognitive behavioural therapy program for insomnia, or to an active control group involving weekly text message sleep tips. Assessments took place at baseline, 6 weeks (post-intervention) and 14 weeks (post-baseline). Co-primary outcomes were symptoms of insomnia and depression at post-intervention (primary endpoint). Intent-to-treat analyses were conducted. The trial is registered with the Australian and New Zealand Clinical Trials Registry, number ACTRN12619001462178. Results: Between October 25, 2019, and September 6, 2020, 264 participants were randomised to receive Sleep Ninja (n = 131) or to the control group (n = 133). Relative to the control group, those allocated to the intervention reported a greater reduction in insomnia symptoms at 6 weeks (95% CI: −2.96 to −0.41, d =.41) and 14 weeks (95% CI: −3.34 to −0.19, d =.39), and a greater reduction in depression symptoms at 6 weeks (95% CI: −3.46 to −0.56, d =.28) but not 14 weeks (p < 1). Change in insomnia mediated change in depression. No adverse events were reported. Conclusions: An app-delivered program for insomnia could be a practical, non-stigmatising and scalable way to reduce symptoms of insomnia and depression among adolescents experiencing difficulties getting enough good quality sleep.