Critical design decisions and user demographics in enhancing real-time digital mental health interventions: A systematic review

Background: Real-time digital mental health interventions, primarily enabled by smartphone technology offer continuous, personalised support, that adapts in response to the changing needs of individuals. Despite being prominently explored in populations with psychiatric disorders, there remains a notable gap in the systematic analysis of demographic characteristics, as well as the foundational design decisions or rules that underpin the personalisation of these interventions. Objectives: (a) Identifying the prevalent design decisions to enable personalisation within real-time digital mental health interventions, (b) the influence of these design decisions on the clinical outcomes of the interventions, and (c) the demographic characteristics of populations with psychiatric disorders targeted by real-time digital health interventions. Methods: Following PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines, a systematic literature review was conducted of peer-reviewed literature focusing on real-time digital interventions in populations with clinically diagnosed psychiatric disorders. We undertook a narrative synthesis to derive the demographics and personalisation design decisions of the interventions and conducted a pooled meta-analysis to evaluate clinical outcomes. Results: Interventions predominantly targeted female and Caucasian demographics, yielding modest clinical improvements. Our analysis identified nine critical personalisation design decisions concerning measurement, intervention, and interactions with health professional with varying influence on clinical outcomes. Conclusion: Understanding the complex nuances of design decisions that shape real-time digital health interventions, as well as identifying which patient demographics benefit most, is fundamental for their effective clinical impact and safe use. Prospero Registration: PROSPERO CRD42020161663.