mHealth
Can phone sensors flag how depressed someone is?
Open access · cc by · source: Europe PMC
In 28 adults carrying a sensor phone for 2 weeks, less regular GPS movement and more phone use tracked higher PHQ-9 scores; normalized entropy classified any vs no depressive symptoms at 86.5% accuracy.
Study at a glance
- Design
- Cross-sectional — 2-week exploratory sensor study: community adults carried Purple Robot; PHQ-9 at baseline correlated with GPS/usage features
- N
- N=28 · 40 recruited; 28 with sufficient sensor data (18 GPS, 21 phone usage); 12 excluded for <50% data coverage
- Population
- US community adults (19–58 years; 20 women, 8 men in the analyzed set) recruited via Craigslist
- Outcome
- Correlation of GPS/phone-usage features with PHQ-9 severity; classification of PHQ-9 ≥5 vs <5
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
Circadian movement r=−.63 (P=.005), normalized entropy and location variance each r=−.58 (P=.012). Usage duration r=.54 (P=.011) and frequency r=.52 (P=.015). A normalized-entropy classifier of PHQ-9 ≥5 vs <5 reached 86.5% accuracy; PHQ-9 regression error was 23.5%.
Methodology
Recruited 40 community adults to carry Purple Robot for 2 weeks (GPS every 5 minutes; screen on/off). Baseline PHQ-9 was correlated with GPS features (circadian movement, normalized entropy, location variance) and phone-usage duration/frequency in the 28 people with enough data.
Limitations
n=28 with a one-time self-report PHQ-9 cannot diagnose clinical depression or prove sensors should replace interviews; 12/40 lacked usable data, so selection bias is possible.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
Phone sensors can track daily movement and usage that correlate with PHQ-9 severity.
In 28 adults carrying a sensor phone for 2 weeks, less regular GPS movement and more phone use tracked higher PHQ-9 (circadian movement r=−.63; usage duration r=.54). Normalized entropy classified PHQ-9 ≥5 vs <5 at 86.5% accuracy.
Evidence for the claim as stated.
A 6-month shared-decision-making app raised activation in schizophrenia care, not symptoms or admissions.
In 194 Danish outpatients, 6 months of an SDM app plus usual care improved patient activation (mean difference 4.39; d=0.33), communication confidence, and decision preparedness, with no effects on symptoms, hope, or admissions.
Scope note — passive GPS/usage correlates of PHQ-9 ≠ an SDM activation RCT in schizophrenia
Limits the claim's scope: a different population, assay, or outcome.
StudiCare’s college waitlist stress effects, MoodGYM’s adult well-being RCT, a 2-week GPS/PHQ-9 sensor study, and a schizophrenia SDM activation trial are all digital mental-health papers, not one pooled app effect.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
StudiCare’s college waitlist stress effects, MoodGYM’s adult well-being RCT, a 2-week GPS/PHQ-9 sensor study, and a schizophrenia SDM activation trial are all digital mental-health papers, not one pooled app effect.
History
When this study was placed
Dated entries from the concept change log — when this paper was added or removed as support, challenge, or qualifier on a claim.
Placed as supporting evidence on mHealth
In 28 adults carrying a sensor phone for 2 weeks, less regular GPS movement and more phone use tracked higher PHQ-9 (circadian movement r=−.63; usage duration r=.54). Normalized entropy classified PHQ-9 ≥5 vs <5 at 86.5% accuracy.
Placed as a scope qualifier on mHealth
In 194 Danish outpatients, 6 months of an SDM app plus usual care improved patient activation (mean difference 4.39; d=0.33), communication confidence, and decision preparedness, with no effects on symptoms, hope, or admissions.
Placed as supporting evidence on mHealth
StudiCare’s college waitlist stress effects, MoodGYM’s adult well-being RCT, a 2-week GPS/PHQ-9 sensor study, and a schizophrenia SDM activation trial are all digital mental-health papers, not one pooled app effect.
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