Cited by 313Mental Health Research TopicsHuman Mobility and Location-Based AnalysisDigital Mental Health Interventions

The relationship between mobile phone location sensor data and depressive symptom severity

Open access
Saeb, Sohrab, Lattie, Emily G., Schueller, Stephen M., Kording, Konrad P., Mohr, David C.·2016·PeerJ

Abstract

Background: Smartphones offer the hope that depression can be detected using passively collected data from the phone sensors. The aim of this study was to replicate and extend previous work using geographic location (GPS) sensors to identify depressive symptom severity. Methods: We used a dataset collected from 48 college students over a 10-week period, which included GPS phone sensor data and the Patient Health Questionnaire 9-item (PHQ-9) to evaluate depressive symptom severity at baseline and end-of-study. GPS features were calculated over the entire study, for weekdays and weekends, and in 2-week blocks. Results: The results of this study replicated our previous findings that a number of GPS features, including location variance, entropy, and circadian movement, were significantly correlated with PHQ-9 scores ( r ’s ranging from −0.43 to −0.46, p -values < .05). We also found that these relationships were stronger when GPS features were calculated from weekend, compared to weekday, data. Although the correlation between baseline PHQ-9 scores with 2-week GPS features diminished as we moved further from baseline, correlations with the end-of-study scores remained significant regardless of the time point used to calculate the features. Discussion: Our findings were consistent with past research demonstrating that GPS features may be an important and reliable predictor of depressive symptom severity. The varying strength of these relationships on weekends and weekdays suggests the role of weekend/weekday as a moderating variable. The finding that GPS features predict depressive symptom severity up to 10 weeks prior to assessment suggests that GPS features may have the potential as early warning signals of depression.

AI snapshot

Written from the paper’s full text.

TL;DR

This study replicated and extended prior work showing that passively collected GPS location features are correlated with depressive symptom severity in a 10-week dataset of 48 college students. Weekend-derived GPS features were more strongly related to PHQ-9 scores than weekday features, and some features predicted follow-up depressive symptoms up to 10 weeks earlier.

Key findings

  • GPS features including location variance, entropy, and circadian movement were significantly correlated with PHQ-9 scores, with abstract-reported \(r\)’s ranging from −0.43 to −0.46, \(p < .05\).
  • In 10-week analyses, follow-up PHQ-9 correlations included location variance \(r = -0.43\), circadian movement \(r = -0.48\), entropy \(r = -0.46\), number of clusters \(r = -0.44\), and home stay \(r = 0.43\).
  • Weekend features were generally stronger than weekday features; for example, weekend follow-up correlations included entropy \(r = -0.55\), normalized entropy \(r = -0.54\), circadian movement \(r = -0.51\), and home stay \(r = 0.50\).
  • Correlations between baseline PHQ-9 and 2-week GPS features diminished over time, while correlations with end-of-study PHQ-9 remained significant regardless of the time point used to calculate features.

Methods

  • Secondary analysis of the StudentLife dataset: 48 college students (38 male, 10 female) followed for 10 weeks, with continuous Android GPS data collected about once every 5 minutes and PHQ-9 administered at baseline and end-of-study.
  • Eleven GPS features were calculated, including eight replicated features plus speed mean, speed variance, and raw entropy; features were computed over the entire 10 weeks, separately for weekdays and weekends, and in overlapping 2-week blocks.
  • Relationships with PHQ-9 scores were assessed using linear correlations, with 1,000 bootstrap subsamples to estimate correlation coefficients and 95% confidence intervals; significance was set at \(p < 0.05\).

Limitations

  • The paper states that many correlation analyses introduced possible alpha slippage, especially for exploratory analyses, and that the study was underpowered to test weekday/weekend differences or differences over time; these findings are therefore preliminary until replicated.
  • The paper states that weekday/weekend was only an operationalization for workday/non-workday and may not fit all people, and that the sample size was relatively small with few depression assessment points.
  • Evident from the text: the sample was college students in a computer science class, predominantly male, with no inclusion/exclusion criteria based on mental health, and only seven participants had clinically meaningful PHQ-9 change, limiting generalizability and change-score analyses.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.7717/peerj.2537

Cites

39 of 39 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 19 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    The study replicated previous findings of a relationship between depressive symptom severity and GPS location features (location variance, entropy, and circadian movement) in the StudentLife dataset.

    “In this study, we were able to replicate our previous findings of the relationship between severity of depressive symptoms and GPS location features, including location variance, entropy, and circadian movement (Saeb et al., 2015a; Saeb et al., 2015b), in the StudentLife dataset (Wang et al., 2014).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Saeb et al., 2015a

      Not checked in the free run.

    • cites Saeb et al., 2015b

      Not checked in the free run.

    • cites Wang et al., 2014

      Not checked in the free run.

  • Findingown data

    Larger correlations were observed on weekends between many GPS features and depression than on weekdays.

    “Indeed, we did see larger correlations on weekends between many of the GPS features and depression, than on weekdays.”
    Quote in the paperSubstantial claim
  • Findingown data

    The correlations between 2-week GPS features and depression scores changed over time.

    “Overall, while these results were consistent with correlation results in Table 3, they indicated that these correlations changed over time.”
    Quote in the paperSubstantial claim
  • Findingown data

    Correlations between baseline PHQ-9 scores and weekend location features were significant in the first weeks immediately following depression assessment, but became non-significant and approached zero at the end of the 10 weeks.

    “Furthermore, correlations between baseline PHQ-9 scores and weekend location features were significant in the first weeks immediately following depression assessment, but quickly became non-significant and approached zero at the end of the 10 weeks (Fig. 3C).”
    Quote in the paperSubstantial claim
  • Findingown data

    For three out of six weekday features (homestay, entropy, and normalized entropy), correlations with follow-up PHQ-9 scores remained significant regardless of extraction time.

    “This was also true for three out of the six features extracted on weekdays (Fig. 3B), including homestay, entropy, and normalized entropy.”
    Quote in the paperNot a substantial claim
  • May combine two claims. 12
  • The quote only partly states this claim. 2
  • Classified as probably not a substantial claim. 15
  • May combine two claims. The quote only partly states this claim.

    Findingown data

    Correlations between the 10-week GPS features and baseline PHQ-9 scores were weaker than with follow-up scores, and none were statistically significant.

    “Correlations between these features and baseline scores were weaker, and none of them were statistically significant.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    All 10-week GPS features significantly related to PHQ-9 scores were also significant when calculated from weekends, whereas only normalized entropy was significantly related as a weekday feature.

    “All of those 10-week features that were significantly related to PHQ-9 scores (see Table 2) were also significant when calculated from weekends, whereas only normalized entropy was significantly related to the scores as a weekday feature.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data

    The correlation between baseline PHQ-9 scores and 2-week GPS features diminished as the features were calculated further from baseline, while correlations with end-of-study PHQ-9 scores remained significant regardless of the time point used to calculate the features.

    “Although the correlation between baseline PHQ-9 scores with 2-week GPS features diminished as we moved further from baseline, correlations with the end-of-study scores remained significant regardless of the time point used to calculate the features.”
    Quote in the paperSubstantial claim
  • The quote only partly states this claim.

    Findingown data

    In the 10-week GPS features, location variance, circadian movement, entropy, home stay, and number of clusters had absolute correlation coefficients ≥0.4 with follow-up PHQ-9 scores.

    “Particularly, location variance, circadian movement, entropy, home stay, and number of clusters all had absolute correlation coefficients |r| ≥ 0.4 with the follow-up PHQ-9 scores.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    Among the 48 participants, PHQ-9 scores decreased from baseline to follow-up for 20 participants and increased for 16; only seven had a clinically meaningful change (absolute change ≥5).

    “For 20 participants, the PHQ-9 scores decreased from baseline to follow-up, while for 16 they increased. However, only seven participants had a change which was clinically meaningful, meaning that the absolute value of the change was greater than or equal to 5.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Premisecitation

    The PHQ-9 is a self-report measure of depression symptom severity.

    “including continuous phone GPS data and the Patient Health Questionnaire 9-item (PHQ-9) (Kroenke, Spitzer & Williams, 2001), a self-report measure of depression symptom severity.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Kroenke, Spitzer & Williams, 2001 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    The 10-week GPS results were consistent with previous findings.

    “Overall, these results were consistent with our previous findings (Saeb et al., 2015a).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Saeb et al., 2015a

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Exploration in small datasets can lead to spurious findings, as seen in the failure to replicate a widely cited paper on phone sensor data to detect mood.

    “While exploration is essential to discovery, it is frequently done in small datasets. This can lead to spurious findings, as has recently been seen in the failure to replicate a widely cited paper (Likamwa et al., 2013) on the use of phone sensor data to detect mood (Ruwaard et al., 2016).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Likamwa et al., 2013

      Not checked in the free run.

    • cites Ruwaard et al., 2016 source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    The StudentLife dataset was collected completely independently of this research group and used a very different sample of college students in a small town, as opposed to the general population in a large city (Chicago) from the first study.

    “This is particularly notable as the StudentLife dataset was collected completely independently of this research group, using a very different sample that consisted of college students in a small town as opposed to the general population in a large city (Chicago) from our first study.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Wang et al., 2014

      Not checked in the free run.

  • May combine two claims.

    Interpretationown data

    While it is difficult to relate raw sensor data or their basic statistics directly to depression, features derived from sensor data are more likely to indicate the presence of depressive symptoms.

    “Therefore, while it is difficult to relate raw sensor data or their basic statistics directly to depression, their features are more likely to indicate the presence of depressive symptoms.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Premisecitation

    A third independent group, Canzian and Musolesi, developed very similar location features and had similar findings.

    “Furthermore, subsequent to our initial publication, a third independent group, Canzian and Musolesi, developed very similar location features and had similar findings (Canzian & Musolesi, 2015).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Canzian & Musolesi, 2015

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    A recent meta-study showed that only one-third to one-half of experimental results reported in psychological science were replicated in later studies.

    “In fact, a recent meta-study showed that only one-third to one-half of experimental results reported in psychological science were replicated in later studies (Open Science, 2015).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Open Science, 2015 source

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductcitation

    The analysis used 1,000 bootstrap subsamples to estimate correlation coefficients and 95% CIs, and only considered coefficients significant if the 95% CI of their associated p-values fell below 0.05.

    “In order to reduce the possibility that results were generated by chance, we created 1,000 bootstrap subsamples (Efron & Tibshirani, 1993) to estimate these correlation coefficients and their 95% confidence intervals (CIs). We only considered those coefficients significant for which the 95% CI of their associated p-values fell below 0.05.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Efron & Tibshirani, 1993 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    The distinction between weekdays and weekend is not necessarily a defining feature for every person.

    “Second, the distinction between weekdays and weekend is not necessarily a defining feature for every person.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    The development of effective behavioral sensing prediction models for mental health will likely require a much larger sample size.

    “Therefore, the development of effective behavioral sensing prediction models for mental health will likely require a much larger sample size.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Interpretationreasoning

    The relationship between features over time may improve the prediction of depression.

    “Thus, the relationship between features over time may improve the prediction.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationnone given

    Even with strong biomarkers, it remains a challenge to develop a system that can passively detect depression with low false positive and false negative rates.

    “However, even with strong biomarkers, it remains a challenge to develop a system that can passively detect depression with low false positive and false negative rates.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Study design and conductnone given

    This study had a relatively small sample size.

    “Finally, this study had a relatively small sample size.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Study design and conductreasoning

    Given the consistency across studies and populations, the number of analyses for the replication analyses is not a significant limitation for this study.

    “In contrast, given the consistency across studies and populations, the number of analyses for the replication analyses is not a significant limitation for this study.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationnone given

    Behavioral sensing studies-including ours-require longer periods of time to capture the slow changes in the disease state and in the behavioral features.

    “Furthermore, behavioral sensing studies—including ours—require longer periods of time to capture the slow changes in the disease state and in the behavioral features.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: Most studies of behavioral sensing in depression only have 2 or 3 assessment points for each individual, which makes the dataset underpowered for investigating the longitudinal relationship between sensor data and depression.
  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationown data

    The finding of the importance of the workday/non-workday distinction highlights the likely importance of variables that moderate the relationship between sensor data and mental health.

    “Our finding of the importance of workday/non-workday distinction highlights the likely importance of the variables that moderate the relationship between sensor data and mental health.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    The findings on weekend and weekday features and temporal relationships contain a large number of correlation analyses, which introduce the possibility of alpha slippage, particularly for the exploratory analyses.

    “First, the findings on weekend and weekday features and temporal relationships contain a large number of correlation analyses which introduce the possibility of alpha slippage, particularly for the exploratory analyses.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    Depression-related disruption in movement first manifests itself only when there are no social constraints (e.g., on non-workdays), but as the disruption in GPS features shifts to manifest itself on workdays, risk of subsequent depression becomes more immediate.

    “This may suggest that depression-related disruption in movement first manifests itself only when there are no social constraints (e.g., on non-workdays), but as the disruption in GPS features shifts to manifest itself on workdays, risk of subsequent depression becomes more immediate.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Premisereasoning

    The StudentLife study extended over 10 weeks, compared to two weeks for the first study, making it a better dataset to explore temporal relationships.

    “The StudentLife study extended over 10 weeks, as compared to two weeks for our first study, making it a better dataset to explore temporal relationships.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Wang et al., 2014

      Not checked in the free run.

  • May combine two claims.

    Study design and conductnone given

    The study was not sufficiently powered to detect workday/non-workday differences in the relationship between GPS and depression, nor the differences in these relationships over time.

    “Furthermore, we were not sufficiently powered to detect workday/non-workday differences in the relationship between GPS and depression, nor the differences in these relationships over time.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    In a previous analysis of the StudentLife dataset, specific aspects about Dartmouth social behavior were used to explore typical 'party' days which did not line up exactly with weekend/weekdays.

    “In a previous analysis of the StudentLife dataset, for example, specific aspects about Dartmouth social behavior were used to explore typical “party” days which did not line up exactly with weekend/weekdays (Wang et al., 2015).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Wang et al., 2015

      Not checked in the free run.

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  • The paper relies on this without support.

    Movement on workdays is determined to some degree by social roles and expectations, while movement on non-workdays is less determined by external demands and more by the individual’s motivational state.

    “Movement on workdays is likely determined to some degree by social roles and expectations, while movement on non-workdays is likely less determined by external demands and more by the individual’s motivational state.”
  • The paper relies on this without support.

    A diagnosis of depression requires the presence of symptoms more days than not for two weeks.

    “The 2-week period was selected as a block of time because a diagnosis of depression requires the presence of symptoms more days than not for two weeks.”
  • The paper relies on this without support.

    Some schools have schedules that do not fall cleanly into a 5-day work week and many people work on weekends.

    “Some schools might have schedules that do not fall cleanly into a 5-day work week and many people clearly work on weekends.”
  • The paper relies on this without support.

    Most studies of behavioral sensing in depression only have 2 or 3 assessment points for each individual, which makes the dataset underpowered for investigating the longitudinal relationship between sensor data and depression.

    “Most studies of behavioral sensing in depression only have 2 or 3 assessment points for each individual, which makes the dataset underpowered for investigating the longitudinal relationship between sensor data—which has much higher frequency—and depression.”
4 of 4

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Student-year breakdown totals 47, not 48

    Minor

    The listed Bachelor's, Master's, and PhD student counts sum to 47, one fewer than the stated 48 students.

    Reported 48 · recomputed 47

  • Pew Research Center citation year differs from reference

    Minor

    The text cites the Pew Research Center as a 2005 source, while the corresponding reference lists 2015.

  • Abstract's correlation range excludes a reported result

    Minor

    The abstract gives a range of −0.43 to −0.46 for the significant GPS-feature correlations, but Table 2 reports −0.48 for circadian movement at follow-up.

3 of 3

Cites

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Research works printed but not linked: 1

  1. Pew Research Center, 2015, U.S. smartphone use in 2015

Cited by

Sorted by citations

Authors
Saeb, S., Lattie, E. G., Schueller, S. M., Kording, K. P., & Mohr, D. C.
Affiliations
Northwestern University (US)
Corresponding author
Mohr, David C.
Venue
PeerJ
Publisher
PeerJ
Published
2016-09-29
Volume
4
Pages
e2537
ISSN
2167-8359 (ISSN-L)
OpenAlex
W2524967876
Cited by
313
References
39
Citations by year
2026: 21 · 2025: 16 · 2024: 40 · 2023: 19 · 2022: 56 · 2021: 51 · 2020: 59 · 2019: 22 · 2018: 20 · 2017: 9
FWCI
24.13
Type
journal article
Language
en
Open access
Locations
  • PeerJ (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
  • eScholarship (California Digital Library) (submittedVersion)
  • eScholarship (California Digital Library) (submittedVersion, cc-by)
Funders
  • US National Institute of Mental Health (P20 MH090318)
  • National Institute of Mental Health (K08 MH 102336)
Topics
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Mental Health Research Topics
  • Social Sciences › Transportation › Human Mobility and Location-Based Analysis
  • Social Sciences › Psychology › Applied Psychology › Digital Mental Health Interventions
Keywords
depression, depression severity, GPS location data, smartphone sensors, passive sensing, PHQ-9, university students, early warning indicators

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