Abstract

Digital health data from consumer wearable devices and smartphones have the potential to improve our understanding of mental illness. However, in conditions like depression, there is not yet a consistent uniform measurement tool whose result can be reliably used as a gold standard measure of depression severity. This work seeks to specify what symptoms and dimensions of depression can be detected using vitals, activity, and sleep monitored by consumer wearable devices. Machine learning models are fit to digital health data and used to detect responses to individual questions from surveys (self-reports) as well as summary scores from these self-reports. For high performing models, feature importance is investigated. Analysis is conducted on preliminary data from 99 participants of an ongoing study with data from the Apple Watch and iPhone along with validated self-reports relevant to depression severity, anhedonia severity, and sleep quality. Receiver operator characteristic area under the curve (ROC AUC) and average precision are used to assess model performance. The digital health sensor data investigated was found to significantly detect five of 74 measures, including overall depression severity and specific symptoms like poor appetite, aspects of anhedonia, and sleep timings (ROC AUC between 0.63 and 0.72). The features these models use in detection vary per detection task and suggest further areas for investigation to specify the right features to look at per symptom.