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Using digital measures as endpoints in mental health trials

Most common mental health disorder (CMHD) trials still rely on clinical outcome assessments (COAs) collected sporadically and miss the depth and breadth of what happens in daily life.

Sensor-based digital health technologies (sDHTs) can capture constructs such as sleep, activity, daily routines, and changes in emotional state, providing a continuous view of how patients are functioning between clinical visits where traditional assessments cannot reach.

This guide helps you decide if and how to use these digital measures as endpoints in CMHD trials. It identifies where digital measures meaningfully complement clinical outcome assessments (COAs), which capture intermittent information on symptoms and functioning, and where they could eventually replace self-reported outcomes. The same endpoint-grade evidence increasingly informs how care delivery teams operationalize measurement-based care and outcomes-based payment decisions.

What this guide helps you do

Find what visit-based scales miss

Identify where digital measures capture day-to-day patterns in sleep, activity, and daily routines between visits.

Be honest about limitations

Document what digital measures can and cannot support today. Use them today to complement clinician‑ and patient‑reported assessments. Some digital measures may eventually replace specific patient‑reported outcomes (PROs) and clinician‑reported outcomes (ClinROs) once they are qualified for that context of use, but that is not the role for most CMHD trials today.

Put endpoints in the right role

Align digital endpoint choices with your CMHD study questions.

Plan for real-world use

Pre-specify how you will handle missing data, gaps in wear time, and encourage adherence. DiMe’s sDHT Navigator includes a section on risk-based approaches for trial monitoring.

Where digital measures fit today

In CMHD research, digital measures are most often used to complement established COAs such as patient-reported outcomes (PROs) and clinician-reported outcomes (ClinROs). Now, they are typically positioned as exploratory or secondary endpoints, not primary endpoints.
  • Sleep regularity, activity patterns, adherence to routines and assessing emotional states are concepts of interest with strong supporting evidence associated with overall clinical status and, in some cohorts, may precede changes in clinical outcomes. Measuring social interactions and engagement in meaningful activities is considered interesting by many experts but these constructs cannot be accurately captured through digital measurement without contextual input from the individual.

  • Some measurable outcomes, such as speech features (e.g., acoustic, linguistic, and paralinguistic features including pauses, prosody, and coherence), are can be reliable captured and show early associations with clinical status in small, heterogeneous studies, but are not yet established for routine clinical endpoint use.

  • Variability in any digital measure may also reflect contextual or behavioral changes (for example, a shift to remote work) rather than the underlying disorder. Due to the reliance on assessing behavior and contextual changes in CMHD, this consideration is especially important.

      • Digital measures in CMHD trials are most often positioned as exploratory or secondary endpoints alongside established clinical outcome assessments, rather than as primary endpoints.
      • Out of 208 endpoints evaluated because they matched the COIs in the conceptual model, 31 were related to CMHD.

      • 47 original research articles evaluated the use of sDHTs for CMHD; virtually all relied on a COA as the reference measure or primary outcome.

      • Capturing social engagement in a privacy-sensitive manner is difficult and relies on GPS, Bluetooth and WiFi connection signals, call and text logs.*

      • Deriving cognitive biomarkers from EEG is an emerging field for safety profiling or the detection of improvements that may not be reportable by patients.

      • Physical activity (n=14) and sleep (n=10) were most commonly recommended in CMHD studies but that is likely a reflection of the maturity of these measures; 15 studies were related to capturing social markers, yet none were included in the digital measure set based on expert and patient input noting they are not measures of “high quality” social interactions.

      *Di Matteo D, Fotinos K, Lokuge S, et al. Automated Screening for Social Anxiety, Generalized Anxiety, and Depression From Objective Smartphone-Collected Data: Cross-sectional Study. J Med Internet Res. 2021;23(8):e28918. doi:10.2196/28918

      Endpoint strategies you can use now

      Each strategy below uses the same structure to help you determine when to use an endpoint, why it helps, and an example of how to use it.

      cmhd-icon Strategy 1: Add real-world, continuous, and objective data
      WHEN TO USE:

      COA scores lack the sensitivity to capture day‑to‑day fluctuations in routines, sleep, physical activity, emotions, social interactions, or meaningful activities that you need to show clinical benefit in CMHD trials.

      WHY IT MATTERS:

      Meaningful aspects of health (MAH), such as those found in the conceptual model, can help you operationalize what matters most to patients, consistent with FDA’s Patient-Focused Drug Development (PFDD) guidance and DiMe’s Measures that Matter framework, strengthening your patient-centered evidence base the FDA increasingly expects in CMHD trial submissions.

      Journal of Affective DisordersIn a 2024 real-world study of 49 patients with bipolar disorder, Anmella and colleagues used a wrist-worn wearable (Empatica E4) to continuously capture electrodermal activity (EDA) across mood episodes and clinical remission. They observed that both tonic (mEDA) and phasic (pEDA) EDA were significantly reduced during acute depressive episodes and rose after the patient reached euthymia, while manic patients showed reductions in both signals after remission. Because EDA is captured passively and continuously in patients’ daily environments, the change-from-baseline in these measures substantiates whether a patient’s self-reported mood status matches a measurable physiologic response, providing a promising objective complement to clinician- and patient-reported assessments in CMHD trials.

      Read the publication

      Journal of Clinical Sleep MedicineNightware, a 2020 FDA breakthrough device is actively being prescribed to people with post-traumatic stress disorder. It’s an Apple Watch app that monitors for the physiological patterns of a trauma-related nightmare. In a 2023 randomized sham-controlled trial of 65 military veterans with PTSD-related nightmares, participants who used the active NightWare device on more than 50% of nights experienced significantly greater improvements in sleep quality than sham users on the Pittsburgh Sleep Quality Index and NightWare Likert, along with greater reductions in sleep latency and nighttime disturbances. The device continuously adapted to each user by building an individualized “stress index” from approximately 1,000 minutes of prior sleep data, demonstrating how wearable-derived physiologic signals may serve as an objective complement to self-reported nightmare severity and PTSD-related sleep outcomes.

      Read the publication

      cmhd-icon Strategy 2: Track trajectories, not just snapshots
      WHEN TO USE:

      Visit-based assessments capture status at single time points but miss the trajectory and timing of change between visits, including how quickly symptoms recur, stabilize, or respond to treatment.

      WHY IT MATTERS:

      It captures trajectories between visits and can reveal patterns that self‑report misses, but only when you plan the analyses in advance and interpret them alongside clinical assessments.

      DO NOT CLAIM:

      That measuring more often automatically makes a trial better. Denser data only translates into stronger results when you understand how the measure behaves in your population, how patients’ experiences vary day to day, and have a clearly defined purpose for the data collection.

      Frontier Psychiatry JournalIn a 31-patient pilot of adults with major depressive disorder, Pedrelli and colleagues, tracked smartphone behavior (calls, texts, activity patterns, app use) and wrist-worn Empatica E4 sensor data (electrodermal activity, skin temperature, heart rate, motion, actigraphy-derived sleep) over 8 weeks of continuous monitoring, alongside the clinician-rated 17-item Hamilton Depression Rating Scale (HDRS-17) administered every two weeks. Machine learning models built on the wearable and smartphone features estimated depression severity with correlations of 0.5 (95% CI 0.45 to 0.55) against the clinician-rated HDRS, with mobile phone engagement, activity level, skin conductance, and heart rate variability emerging as the most predictive features. The study illustrates how a longitudinal behavioral summary derived from passive sensors can be tracked against a clinician-administered COA across time in a CMHD trial, complementing rather than replacing the rating-scale assessment.

      Read the article

      xtalks webinarDelix Therapeutics has developed DLX-001 (zalsupindole), a novel oral non-hallucinogenic neuroplastogen inspired by 5-MeO-DMT (mebufotenin) for major depressive disorder (MDD). In the DLX-001 Phase 1b study (N= 18 adults with MDD), Delix leveraged the Cumulus Neuroscience NeuLogiq® Platform – an AI-based, multi- domain digital biomarker platform that pairs an FDA 510(k)-cleared dry sensor EEG headset with gamified tablet-based assessments across multiple domains of brain function. The use of NeuLogiq enabled repeated digital sampling of qEEG/ERP biomarkers, and cognitive safety endpoints, complementing conventional trial measures, including clinician-rated symptom scales (MADRS and HAM-D-17), PK, qEEG, PSG, and safety assessments. Across baseline, dosing, and follow-up, the platform collected 339 digital assessment sessions, combining dry-EEG tasks and brief cognitive assessments, with EEG-based sessions timed around expected peak drug exposure where feasible. This sampling design allowed analyses to examine acute, cumulative, cohort, and exposure effects adding temporal and mechanistic context beyond visit-level clinical outcomes. Resting-state qEEG analyses and task-based event related potential (ERP) Event-related potentials (ERPs) are time-locked brain responses to specific events or stimuli. The NeuLogiq platform incorporates a patented technology to enable precise time-synchronization to the wireless headset. – analyses, including Auditory Steady-State Response (ASSR) readouts, captured individual-participant trajectories in neurophysiological signals relevant to DLX-001’s proposed neuroplasticity-related mechanism. This is particularly valuable in early-phase studies where there is a need to characterize drug mechanisms and within-participant change over time, in addition to clinical treatment outcomes. Repeated cognitive testing using the NeuLogiq Symbol Swap assessment – a gamified and validated version of the well-established digit symbol substitution test (DSST) – provided data showing typical patterns task learning, and no evidence of acute or delayed cognitive impairment related to the drug. The case illustrates how digital biomarkers can provide complementary information to traditional registered clinical trials endpoints by adding temporal resolution and mechanistic context, rather than replacing or serving as a direct comparator to clinician-administered assessments.

      Watch the webinar

      cmhd-icon Strategy 3: Explore subgroup or response patterns
      WHEN TO USE:

      You want to explore heterogeneity in longitudinal CMHD data, such as whether different individuals show distinct patterns of change in sleep and activity that co‑occur with symptom trajectories.

      WHY IT MATTERS:

      Supports stratification of heterogeneous CMHD populations and exploratory identification of subgroups more or less likely to benefit from a treatment, provided you plan analyses in advance, account for multiplicity and confounding, and use findings to inform future trial design rather than treatment decisions.

      EXAMPLE:

      Explore subgroup or response patternsIn a (prepublication) population-scale longitudinal analysis of patients on an SSRI, Headlamp Health used its Lumos AI platform to track response trajectories over time and identified four discrete responder clusters (high, partial, insufficient, and low responders). The high- and low-responder clusters shared the same top diagnoses, but differed in augmentation pattern: the difference associated with worsening from baseline came down to one augmentation choice (a CNS stimulant versus an amino ketone). Findings like these are best used to inform downstream prospective enrichment trials or pre-specified confirmatory subgroup analyses, not as rules for individual treatment decisions, and they illustrate the kind of heterogeneity that longitudinal CMHD data can surface when symptom trajectories and treatment patterns are modeled together.

      Unlocking pivotal-trial use

      Today, digital measures support exploratory and secondary endpoints in CMHD trials. To develop a primary endpoint, support real-time clinical alerts in routine care, drive individual treatment decisions, or carry labeling claims, the field still needs:

      • Reproducible measure performance across diagnoses, severities, and care settings
      • Qualification of the meaningful aspect of health, the measure, and the context of use as a triad for each specific decision context
      • Repeated demonstration of the value
      • Engagement and adherence patterns characterized in the populations the measure is intended to serve
      • Direct engagement with regulatory authorities to align on acceptable evidentiary standards before submission

      Navigate and implement patient-centered endpoints

      DiMe’s sDHT Adoption Navigator is an AI-enabled companion resource to support your specific project stage, whether you need a step-by-step roadmap or a deep-dive search into selecting digital endpoints.

      What the field needs to answer

      Some questions remain unsettled, and teams should be honest about that. Wherever you position your digital endpoints (exploratory, secondary, or primary in pivotal trials), design your trial so that it contributes to answering at least one of these questions.
      Which digital measures generalize within an indication, and which need indication-specific definitions?

      CMHD populations are large enough to support measurement strategies that capture shared concepts, as well as indication-specific endpoint development where the underlying biology and behavior diverge. Some measures, such as sleep, activity, and behavioral measures, may be generalizable across disorders, while others may require indication-specific operationalization due to differences in clinical context, care pathways, and how constructs manifest across conditions. For example, medication adherence (an emerging measure) is not universally applicable across CMHD populations, as not all individuals are prescribed medicines. Additional research is needed to determine the extent to which CMHD digital measures can be used to phenotype across and within disorders, and where disorder-specific digital measures may add incremental value at the indication level.

      How can you optimize for translatability?

      Prioritize consistently collecting a set of digital measures and adhere to reporting requirements, metadata structures, and ontologies to enable cross‑study comparability and accelerate adoption.

      What do regulators, payors, and professional societies need to see?

      Several CMHD-specific considerations impact regulatory acceptance such as high placebo response rates, CMHD that are highly episodic, frequent comorbid conditions, and validation against inherently subjective constructs. The section below includes several resources that can be used to address these questions and build a comprehensive regulatory strategy.

      Next steps

      Now that you’ve explored using digital measures as endpoints in mental health trials, take the next step by learning how to use the same measures for exploratory phenotyping.