In summary

Digital biomarkers provide objective, continuous data through devices like smartphone apps and wearables that have the potential to enhance the accuracy and timeliness of mental health assessments
These tools have the potential to enable real-time monitoring and personalized interventions, which could complement conventional interventions and help inform treatment decisions
Although digital biomarkers show promise for early detection and personalized treatment, they face challenges such as data complexity, specificity issues, and privacy concerns, necessitating ongoing research and development

There are significant gaps in the diagnosis, treatment, and monitoring of mental health conditions that affect millions globally.^1,2In other fields of medicine, digital biomarkers have enhanced diagnosis, guided treatment decisions, and improved patient outcomes by providing more precise and individualized care.³Digital technologies are emerging as promising tools to support more comprehensive, accessible, and personalized care, although they remain in the early stages of development.^4–6 Digital biomarkers—objective, quantifiable physiological and behavioral data collected through digital devices—are being explored for their potential to improve mental health care.^3,6–12 While many digital biomarkers are still under validation, in the future they may offer a novel approach by leveraging technology to provide a more comprehensive understanding of mental health.^3,4,12

Demystifying Digital Biomarkers

Digital biomarkers offer a broader range of continuous data collection options or augmented versions of traditional measures.^4,7Digital biomarkers provide objective sensor data, compared with some traditional measures used in trials or at clinic appointments that can rely on self-report and be spaced weeks or months apart.⁴ By providing continuous self-reporting and potentially more objective passive monitoring, digital biomarkers have the potential to significantly enhance and expand traditional approaches to mental health care in the future.^4,13,14 Additionally, certain technologies are showing early promise in psychiatry, such as smartphone apps for ecological momentary assessments and wearables for tracking sleep, measuring heart rate, and breathing patterns.^13,14

The Promise of Digital Biomarkers

Digital biomarkers can serve as endpoints in clinical trials, allowing researchers to monitor responses in real time without invasive procedures.¹⁵Currently, several small- to moderate-sizedstudies using a range of active and passive digital assessment measures related to functioning in schizophrenia have been launched.^8–11 Looking to examples from the neurological disorders field, one trial is using actigraphy—a wrist-worn device that measures kinetic energy as an outcome measure of the circadian rest-activity cycle.⁹Additionally, another study will use a passive smartphone monitoring application to measure social behavior.¹⁰

There are many potential applications of digital biomarkers in mental health care, including:

Monitoring patient status: Improved monitoring could facilitate early detection of symptom changes and potential relapse risks.^3,13 For instance, a 2021 study by Rykov et al. used digital biomarkers to develop a model for identifying individuals at high risk of developing depression.¹⁶ However, while the study identified several reliable associations, it found that digital biomarkers had limited effectiveness in detecting depression across the entire sample of working adults, underscoring the need for continued research to validate these tools.¹⁶
Patient characterization: Personalized data patterns may allow for more tailored treatment approaches.^3,17
Treatment response: Monitoring treatment responses and identifying potential side effects could enable more precise adjustments to treatment plans.³

For clinical use, digital biomarkers could potentially offer more substantial applications. Continuous data streams from these digital tools enable the possibility of tailored interventions based on individual need and real-time feedback.³ Furthermore, digital tools offer the potential to empower patients to track their progress and actively participate in their care journey.^3,14

Challenges and Considerations

Although digital biomarkers offer promising potential for mental health assessment and treatment, they are not without limitations. The complexity and volume of data generated by digital biomarkers require advanced analytics and an interdisciplinary approach for accurate interpretation.^{3, 18,19} Large datasets are essential for establishing robust patterns and ensuring generalizability.²⁰However, specificity can be challenging, as a single digital signal may reflect multiple mental health conditions. For instance, a decrease in physical activity and limited social interaction can be observed in both schizophrenia and mood disorders.²¹ Additionally, there are ethical considerations, including the feasibility and justification of using digital measures, as well as privacy concerns. Ensuring data privacy and security requires robust safeguards.^3,18,22Furthermore, integrating digital biomarkers into routine clinical practice necessitates that healthcare practitioners are adequately trained to interpret and utilize digital health data effectively.³

What Does the Digital Future Hold?

Digital biomarkers hold immense potential to enhance mental health care. By providing passive monitoring of objective measures that potentially index clinically relevant phenomena, these technologies may offer additional insights about mental health conditions.²³ This aligns with the goals of precision psychiatry, which aim to enhance early detection, tailor treatments to individual needs, and ultimately improve patient outcomes.^3,24 While challenges such as data standardization, privacy concerns, and regulatory oversight exist, ongoing research and advancements are addressing these issues.³ As digital biomarkers continue to evolve, they have the potential to improve the field of mental health.