The general goal is to design, develop and evaluate a personalized, self-guided and trans-diagnostic internet-based intervention to prevent anxiety and depression, based on predictive risk algorithms and decision support systems (DSS), in Spanish and Chilean adult population.
Methods: We will conduct a three-arm parallel randomized controlled trial with one year of follow-up. A total of 2,595 depression- or/and anxiety-free participants (865 per group), aged 18-65, will be recruited and randomly assigned to one of two intervention groups or to the usual-care group (in a 1:1:1 ratio). Both interventions, Pandora-1 and Pandora-2, will be implemented via a smartphone application, the Pandora App. Pandora-1 is a self-guided and transdiagnostic intervention that includes 4 interactive intervention modules (move more, sleep better, improve relationships and emotional well-being), as well as predictive risk algorithms, decision support systems, and monitoring and feedback to implement personalized plans for the prevention of anxiety and depression. Pandora-2 is a psycho-educative intervention with predictive risk algorithms, minimally interactive and without personalization. The primary outcome is the combined rate of the onset of anxiety or depression (DSM-V diagnoses as measured by the CIDI interview) at 6 and 12 months. The secondary outcomes are the reduction of depressive (PHQ-9) and anxious (GAD-7) symptoms, risk of depression and anxiety (predictD and predictA risk algorithms), and the improvement of mental \& physical quality of life (SF-12), as well as acceptation and satisfaction with Pandora apps (u-MARS) and adverse effects (ad hoc questionnaire), which will be assessed at 1, 6 and 12 months. As mediators will be measured social support (Duke-UNC-2 items), physical activity (BPAQ-2), sleep (AIS-5), and repetitive negative thinking (PTQ-9) evaluated at 1, 6 and 12 months. We will use ActiGraph-GT3X accelerometers to assess physical activity and sleep at 1 and 6 months, in a subsample of 404 sedentary study participants.