Advancing pediatric mental health
intervention through multimodal
digital phenotyping

Chapter 1 establishes technical feasibility and research context for ChAMP, a smartphone-based platform for collecting multimodal signals associated with childhood anxiety, ADHD, and depression during brief structured behavioral tasks. In 101 children ages four to eight, machine learning classifiers achieved 70 to 73 percent balanced accuracy, comparable to established parent-report instruments. This chapter also introduces an ethical framework for deploying technologies such as ChAMP, offering guidance for real-world implementation.

Chapter 2 asks which of the six sensors actually carry the signal, and which can come off. Across 90 children, classifier AUCs ranged from 0.69 to 0.91 across diagnostic targets, and a practicality framework formalizes the tradeoff between sensor burden and performance. The chapter also reports the first pediatric validation of trapezius-derived ECG using wearables: an upper-back placement recovered heart rate within 2.3 to 2.5 bpm of chest ECG during structured tasks, with quality gating retaining 73 to 77 percent of children.

Chapter 3 identifies the gap between detection and family action and builds the infrastructure to close it. Across 299 caregivers, mental health literacy independently predicted help-seeking behavior (OR 1.52), indicating that what families most lack is not information but frameworks for action. A complementary clinic-based feasibility study found that 61 percent of survey completers in a diverse pediatric sample expressed openness to wearable-paired assessment (48 percent of all approached families), providing preliminary evidence that the protocols developed in Chapters 1 and 2 are acceptable to real families in real clinical settings. Intensive cross-national customer discovery, iterative co-design, multi-stakeholder workshop deployments, and the founding of a spinout company connecting these tools to families demonstrate that research translation requires parallel tracks of scientific validation and responsiveness to family needs.