Nilam Ram studies the dynamic interplay of psychological and media processes and how they change from moment-to-moment and across the life span.

Nilam’s research grows out of a history of studying change. After completing his undergraduate study of economics, he worked as a currency trader, frantically tracking and trying to predict the movement of world markets as they jerked up, down and sideways. Later, he moved on to the study of human movement, kinesiology, and eventually psychological processes - with a specialization in longitudinal research methodology. Generally, Nilam studies how short-term changes (e.g., processes such as learning, information processing, emotion regulation, etc.) develop across the life span, and how longitudinal study designs contribute to generation of new knowledge. Current projects include examinations of age-related change in children’s self- and emotion-regulation; patterns in minute-to-minute and day-to-day progression of adolescents’ and adults’ emotions; and change in contextual influences on well-being during old age. He is developing a variety of study paradigms that use recent developments in data science and the intensive data streams arriving from social media, mobile sensors, and smartphones to study change at multiple time scales.

Academic Appointments

Stanford Advisees

  • Doctoral Dissertation Reader (AC)
    Sabrina Huang
  • Doctoral (Program)
    Michelle Ng

All Publications

  • The Idiosyncrasies of Everyday Digital Lives: Using the Human Screenome Project to Study User Behavior on Smartphones. Computers in human behavior Brinberg, M. n., Ram, N. n., Yang, X. n., Cho, M. J., Sundar, S. S., Robinson, T. N., Reeves, B. n. 2021; 114


    Most methods used to make theory-relevant observations of technology use rely on self-report or application logging data where individuals' digital experiences are purposively summarized into aggregates meant to describe how the average individual engages with broadly defined segments of content. This aggregation and averaging masks heterogeneity in how and when individuals actually engage with their technology. In this study, we use screenshots (N > 6 million) collected every five seconds that were sequenced and processed using text and image extraction tools into content-, context-, and temporally-informative "screenomes" from 132 smartphone users over several weeks to examine individuals' digital experiences. Analyses of screenomes highlight extreme between-person and within-person heterogeneity in how individuals switch among and titrate their engagement with different content. Our simple quantifications of textual and graphical content and flow throughout the day illustrate the value screenomes have for the study of individuals' smartphone use and the cognitive and psychological processes that drive use. We demonstrate how temporal, textual, graphical, and topical features of people's smartphone screens can lay the foundation for expanding the Human Screenome Project with full-scale mining that will inform researchers' knowledge of digital life.

    View details for DOI 10.1016/j.chb.2020.106570

    View details for PubMedID 33041494

    View details for PubMedCentralID PMC7543997

  • Time for the Human Screenome Project NATURE Reeves, B., Robinson, T., Ram, N. 2020; 577 (7790): 314–17

    View details for Web of Science ID 000509570100014

    View details for PubMedID 31942062

  • Screenomics: A New Approach for Observing and Studying Individuals' Digital Lives. Journal of adolescent research Ram, N. n., Yang, X. n., Cho, M. J., Brinberg, M. n., Muirhead, F. n., Reeves, B. n., Robinson, T. N. 2020; 35 (1): 16–50


    This study describes when and how adolescents engage with their fast-moving and dynamic digital environment as they go about their daily lives. We illustrate a new approach - screenomics - for capturing, visualizing, and analyzing screenomes, the record of individuals' day-to-day digital experiences.Over 500,000 smartphone screenshots provided by four Latino/Hispanic youth, age 14-15 years, from low-income, racial/ethnic minority neighborhoods.Screenomes collected from smartphones for one to three months, as sequences of smartphone screenshots obtained every five seconds that the device is activated, are analyzed using computational machinery for processing images and text, machine learning algorithms, human-labeling, and qualitative inquiry.Adolescents' digital lives differ substantially across persons, days, hours, and minutes. Screenomes highlight the extent of switching among multiple applications, and how each adolescent is exposed to different content at different times for different durations - with apps, food-related content, and sentiment as illustrative examples.We propose that the screenome provides the fine granularity of data needed to study individuals' digital lives, for testing existing theories about media use, and for generation of new theory about the interplay between digital media and development.

    View details for DOI 10.1177/0743558419883362

    View details for PubMedID 32161431

    View details for PubMedCentralID PMC7065687

  • Emotional Experience Improves With Age: Evidence Based on Over 10 Years of Experience Sampling PSYCHOLOGY AND AGING Carstensen, L. L., Turan, B., Scheibe, S., Ram, N., Ersner-Hershfield, H., Samanez-Larkin, G. R., Brooks, K. P., Nesselroade, J. R. 2011; 26 (1): 21-33


    Recent evidence suggests that emotional well-being improves from early adulthood to old age. This study used experience-sampling to examine the developmental course of emotional experience in a representative sample of adults spanning early to very late adulthood. Participants (N = 184, Wave 1; N = 191, Wave 2; N = 178, Wave 3) reported their emotional states at five randomly selected times each day for a one week period. Using a measurement burst design, the one-week sampling procedure was repeated five and then ten years later. Cross-sectional and growth curve analyses indicate that aging is associated with more positive overall emotional well-being, with greater emotional stability and with more complexity (as evidenced by greater co-occurrence of positive and negative emotions). These findings remained robust after accounting for other variables that may be related to emotional experience (personality, verbal fluency, physical health, and demographic variables). Finally, emotional experience predicted mortality; controlling for age, sex, and ethnicity, individuals who experienced relatively more positive than negative emotions in everyday life were more likely to have survived over a 13 year period. Findings are discussed in the theoretical context of socioemotional selectivity theory.

    View details for DOI 10.1037/a0021285

    View details for Web of Science ID 000288590800003

    View details for PubMedID 20973600

    View details for PubMedCentralID PMC3332527

  • Partner Pain and Affect in the Daily Lives of Older Couples. The journals of gerontology. Series B, Psychological sciences and social sciences Potter, S., Rocke, C., Gerstorf, D., Brose, A., Kolodziejczak, K., Hoppmann, C., Ram, N., Drewelies, J. 2021


    OBJECTIVES: The susceptibility of older adults' affect to fluctuations in their own health (within-person health sensitivity) indicates how they handle everyday health challenges. In old age, affective well-being is often increasingly influenced by close others, yet it is unknown whether older adults' affect is additionally susceptible to fluctuations in their spouse's health (within-partnership health sensitivity) and the extent to which age and relationship satisfaction moderate such associations.METHODS: Parallel sets of multi-level actor-partner interdependence models are applied to self-reported health (feelings of pain/discomfort) and positive and negative affect, obtained 6 times a day over 7 consecutive days from two independent samples, the Berlin Couple Dynamics Study (N= 87 couples; Mage= 75 years; M relationship length= 46 years) and the Socio-Economic Panel Couple Dynamics Study (N= 151 couples; Mage= 72 years; M relationship length= 47 years).RESULTS: Husbands and wives had lower positive affect and higher negative affect in moments when they reported more pain (within-person health sensitivity) and when their respective spouse reported more pain (within-partnership health sensitivity). Tests for moderation suggest that within-person, but not within-partnership, health sensitivity is lower at older ages and higher with more satisfying relationships.DISCUSSION: These findings empirically illustrate lifespan notions that close relationships shape time-varying health-affect links and thus underscore the theoretical and practical utility of examining social contextual antecedents of older adults' everyday affective well-being.

    View details for DOI 10.1093/geronb/gbab188

    View details for PubMedID 34653253

  • Sensitization in situ: Identifying interindividual differences in adolescents intraindividual responsiveness to daily interparental conflict FAMILY RELATIONS Sloan, C. J., Fosco, G. M., Ram, N. 2021

    View details for DOI 10.1111/fare.12604

    View details for Web of Science ID 000704344300001

  • Healthy Aging-Relevant Goals: The Role of Person-Context Co-construction. The journals of gerontology. Series B, Psychological sciences and social sciences Wahl, H., Hoppmann, C. A., Ram, N., Gerstorf, D. 2021; 76 (Supplement_2): S181-S190


    OBJECTIVES: This article considers how individuals' motivation for healthy aging manifests within the myriad of different contexts that older adults are embedded in as they move through later life.METHODS: Drawing on the concept of co-construction, we argue that persons and contexts both contribute to the emergence, maintenance, and disengagement from healthy aging relevant goals in adulthood and old age.RESULTS: To promote the understanding of such co-constructive dynamics, we propose four conceptual refinements of previous healthy aging models. First, we outline various different, often multidirectional, ways in which persons and contexts conjointly contribute to how people set, pursue, and disengage from health goals. Second, we promote consideration of context as involving unique, shared, and interactive effects of socio-economic, social, physical, care/service, and technology dimensions. Third, we highlight how the relevance, utility, and nature of these context dimensions and their role in co-constructing health goals change as individuals move through the Third Age, the Fourth Age, and a terminal stages of life. Finally, we suggest that these conceptual refinements be linked to established (motivational) theories of lifespan development and aging.DISCUSSIONS: In closing, we outline a set of research questions that promise to advance our understanding of the mechanisms by which contexts and aging persons co-construct healthy aging relevant goals and elaborate on the applied significance of this approach for common public health practices.

    View details for DOI 10.1093/geronb/gbab089

    View details for PubMedID 34515774

  • Visual Model Fit Estimation in Scatterplots: Influence of Amount and Decentering of Noise IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS Reimann, D., Blech, C., Ram, N., Gaschler, R. 2021; 27 (9): 3834-3838


    Scatterplots with a model enable visual estimation of model-data fit. In Experiment 1 (N = 62) we quantified the influence of noise-level on subjective misfit and found a negatively accelerated relationship. Experiment 2 showed that decentering of noise only mildly reduced fit ratings. The results have consequences for model-evaluation.

    View details for DOI 10.1109/TVCG.2021.3051853

    View details for Web of Science ID 000679532000018

    View details for PubMedID 33444142

  • Positive and negative affect are associated with salivary cortisol in the everyday life of older adults: A quantitative synthesis of four aging studies. Psychoneuroendocrinology Pauly, T., Drewelies, J., Kolodziejczak, K., Katzorreck, M., Lucke, A. J., Schilling, O. K., Kunzmann, U., Wahl, H., Ditzen, B., Ram, N., Gerstorf, D., Hoppmann, C. A. 2021; 133: 105403


    Research on time-fluctuating links between positive affect and cortisol is inconsistent and mostly based on young to middle-aged samples. The current project investigated how moment-to-moment changes in positive and negative affect are associated with moment-to-moment changes in cortisol levels in older adults' daily lives and whether those associations are moderated by differences in health status (as indicated by the number of comorbidities). Affect and cortisol data collected in four separately conducted momentary assessment studies with parallel protocols were pooled to obtain a sample of N=476 individuals aged 56-88 years (Mage=71.9, SD=6.6; 52% female). Participants provided affect reports and collected salivary cortisol 5-7 times a day for a 7-day period and reported the presence of 13 different health conditions. Data were analyzed using multilevel models, with time since waking, daily behaviors associated with cortisol secretion, age, and sex controlled. Feeling more positive affect than usual was associated with lower momentary cortisol. In contrast, feeling more negative affect than usual was associated with higher momentary cortisol. Associations of momentary positive and negative affect with cortisol were weaker among participants in worse as compared to those in better health. Trait positive affectivity was associated with more curvature of waking cortisol profiles and trait negative affectivity was associated with smaller cortisol awakening responses. Findings suggest that HPA axis responses fluctuate with everyday changes in positive and negative affect in older adults, and that higher HPA reactivity may indicate preserved health in this age group.

    View details for DOI 10.1016/j.psyneuen.2021.105403

    View details for PubMedID 34536776

  • Using technology to unobtrusively observe relationship development JOURNAL OF SOCIAL AND PERSONAL RELATIONSHIPS Brinberg, M., Vanderbilt, R., Solomon, D., Brinberg, D., Ram, N. 2021
  • Sociohistorical Change in Urban Older Adults' Perceived Speed of Time and Time Pressure. The journals of gerontology. Series B, Psychological sciences and social sciences Lockenhoff, C. E., Drewelies, J., Duezel, S., Steinhagen-Thiessen, E., Demuth, I., Freund, A. M., Staudinger, U. M., Lindenberger, U., Wagner, G. G., Ram, N., Gerstorf, D. 2021


    OBJECTIVES: Perceptions of time are shaped by sociohistorical factors. Specifically, economic growth and modernization often engender a sense of acceleration. Research has primarily focused on one time perception dimension (perceived time pressure) in one subpopulation (working-age adults), but it is not clear whether historical changes extend to other dimensions (e.g., perceived speed of time) and other subpopulations, such as older adults who are no longer in the workforce and experience age-related shifts in time perception. We therefore examined sociohistorical and age-related trends in two dimensions of time perception in two cohorts of urban older adults.METHOD: Using propensity score matching for age and education, samples were drawn from the Berlin Aging Study (1990-1993, n = 256, Mage = 77.49) and the Berlin Aging Study-II (2009-2014, n = 248, Mage = 77.49). Cohort differences in means, variances, covariance, and correlates of perceived speed of time and time pressure were examined using multigroup SEM.RESULTS: There were no cohort differences in the perceived speed of time, but later-born cohorts reported more time pressure than earlier-born cohorts. There were no significant age differences, but perceptions of speed of time were more heterogeneous in the 1990s than in the 2010s. Cohorts did not differ in how time perceptions were associated with sociodemographic, health, cognitive, and psychosocial correlates.DISCUSSION: These findings document sociohistorical trends toward greater perceived time pressure and reduced heterogeneity in perceived speed of time among later-born urban adults. Conceptualizations of social acceleration should thus consider the whole adult life span.

    View details for DOI 10.1093/geronb/gbab094

    View details for PubMedID 34180501

  • Do New Romantic Couples Use More Similar Language Over Time? Evidence from Intensive Longitudinal Text Messages. The Journal of communication Brinberg, M., Ram, N. 2021; 71 (3): 454-477


    The digital text traces left by computer-mediated communication (CMC) provide a new opportunity to test theories of relational processes that were originally developed through observation of face-to-face interactions. Communication accommodation theory, for example, suggests that conversation partners' verbal (and non-verbal) behaviors become more similar as relationships develop. Using a corpus of 1+ million text messages that 41 college-age romantic couples sent to each other during their first year of dating, this study examines how linguistic alignment of new romantic couples' CMC changes during relationship formation. Results from nonlinear growth models indicate that three aspects of daily linguistic alignment (syntactic-language style matching, semantic-latent semantic analysis, overall-cosine similarity) all exhibit exponential growth to an asymptote as romantic relationships form. Beyond providing empirical support that communication accommodation theory also applies in romantic partners' CMC, this study demonstrates how relational processes can be examined using digital trace data.

    View details for DOI 10.1093/joc/jqab012

    View details for PubMedID 34335083

  • Describing and Controlling Multivariate Nonlinear Dynamics: A Boolean Network Approach. Multivariate behavioral research Yang, X., Ram, N., Molenaar, P. C., Cole, P. M. 2021: 1–30


    We introduce a discrete-time dynamical system method, the Boolean network method, that may be useful for modeling, studying, and controlling nonlinear dynamics in multivariate systems, particularly when binary time-series are available. We introduce the method in three steps: inference of the temporal relations as Boolean functions, extraction of attractors and assignment of desirability based on domain knowledge, and design of network control to direct a psychological system toward a desired attractor. To demonstrate how the Boolean network can describe and prescribe control for emotion regulation dynamics, we applied this method to data from a study of how children use bidding to an adult and/or distraction to regulate their anger during a frustrating task (N=120, T=480seconds). Network control strategies were designed to move the child into attractors where anger is OFF. The sample shows heterogeneous emotion regulation dynamics across children in 22 distinct Boolean networks, and heterogeneous control strategies regarding which behavior to perturb and how to perturb it. The Boolean network method provides a novel method to describe nonlinear dynamics in multivariate psychological systems and is a method with potential to eventually inform the design of interventions that can guide those systems toward desired goals.

    View details for DOI 10.1080/00273171.2021.1911772

    View details for PubMedID 33874843

  • Concordance of mother-child respiratory sinus arrythmia is continually moderated by dynamic changes in emotional content of film stimuli. Biological psychology Ravindran, N., Zhang, X., Green, L. M., Gatzke-Kopp, L. M., Cole, P. M., Ram, N. 2021: 108053


    Evidence suggests that concordance between parent and child physiological states is an important marker of interpersonal interaction. However, studies have focused on individual differences in concordance, and we have limited understanding of how physiological concordance may vary dynamically based on the situational context. We examined whether mother-child physiological concordance is moderated by dynamic changes in emotional content of a film clip they viewed together. Second-by-second estimates of respiratory sinus arrythmia were obtained from mothers and children (N=158, Mchild age = 45.16 months) as they viewed a chase scene from a children's film. In addition, the film clip's negative emotional content was rated second-by-second. Results showed that mother-child dyads displayed positive physiological concordance only in seconds when there was an increase in the clip's negative emotional content. Thus, dynamic changes in mother-child physiological concordance may indicate dyadic responses to challenge.

    View details for DOI 10.1016/j.biopsycho.2021.108053

    View details for PubMedID 33617928

  • Dyadic analysis and the reciprocal one-with-many model: Extending the study of interpersonal processes with intensive longitudinal data. Psychological methods Brinberg, M., Ram, N., Conroy, D. E., Pincus, A. L., Gerstorf, D. 2021


    Newly available data streams from experience sampling studies and social media are providing new opportunities to study individuals' dyadic relations. The "one-with-many" (OWM) model (Kenny et al., 2006; Kenny & Winquist, 2001) was specifically constructed for and is used to examine features of multiple dyadic relationships that one set of focal persons (e.g., therapists, physicians) has with others (e.g., multiple clients, multiple patients). Originally, the OWM model was constructed for and applied to cross-sectional data. However, the model can be extended to accommodate and may be particularly useful for the analysis of intensive repeated measures data now being obtained through experience sampling and social media. This article (a) provides a practical tutorial on fitting the OWM model, (b) describes how the OWM model is extended for analysis of repeated measures data, and (c) illustrates application of the OWM model using reports about interpersonal behavior and benefits individuals experienced in 64,111 social interactions during 9 weeks of study (N = 150). Our presentation highlights the utility of the OWM model for examining interpersonal processes in everyday life. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

    View details for DOI 10.1037/met0000380

    View details for PubMedID 33475420

  • Screenomics: A Framework to Capture and Analyze Personal Life Experiences and the Ways that Technology Shapes Them. Human-computer interaction Reeves, B. n., Ram, N. n., Robinson, T. N., Cummings, J. J., Giles, C. L., Pan, J. n., Chiatti, A. n., Cho, M. J., Roehrick, K. n., Yang, X. n., Gagneja, A. n., Brinberg, M. n., Muise, D. n., Lu, Y. n., Luo, M. n., Fitzgerald, A. n., Yeykelis, L. n. 2021; 36 (2): 150–201


    Digital experiences capture an increasingly large part of life, making them a preferred, if not required, method to describe and theorize about human behavior. Digital media also shape behavior by enabling people to switch between different content easily, and create unique threads of experiences that pass quickly through numerous information categories. Current methods of recording digital experiences provide only partial reconstructions of digital lives that weave - often within seconds - among multiple applications, locations, functions and media. We describe an end-to-end system for capturing and analyzing the "screenome" of life in media, i.e., the record of individual experiences represented as a sequence of screens that people view and interact with over time. The system includes software that collects screenshots, extracts text and images, and allows searching of a screenshot database. We discuss how the system can be used to elaborate current theories about psychological processing of technology, and suggest new theoretical questions that are enabled by multiple time scale analyses. Capabilities of the system are highlighted with eight research examples that analyze screens from adults who have generated data within the system. We end with a discussion of future uses, limitations, theory and privacy.

    View details for DOI 10.1080/07370024.2019.1578652

    View details for PubMedID 33867652

    View details for PubMedCentralID PMC8045984

  • Political context is associated with everyday cortisol synchrony in older couples. Psychoneuroendocrinology Pauly, T., Kolodziejczak, K., Drewelies, J., Gerstorf, D., Ram, N., Hoppmann, C. A. 2020; 124: 105082


    Prior research with predominantly younger to middle-aged samples has demonstrated that couples' cortisol levels covary throughout the day (cortisol synchrony). Not much is known about cortisol synchrony in old age, and its potential broader societal correlates. The current study investigates associations between the socio-political context and cortisol synchrony as observed in older couples' daily lives. 160 older German couples (Mage =72 years, range: 56-89) provided salivary cortisol samples 7 times daily for a 7-day period. Socio-political context was quantified using state-specific voting data from the 2017 German federal election along the left-right political spectrum. Multilevel models controlling for diurnal cortisol rhythm, food intake, sex, age, body mass index, education, and individual-level political orientation revealed evidence for synchrony in partners' cortisol fluctuations (b=0.03, p<.001). The extent of cortisol synchrony was moderated by left-right political context, such that older couples living in a federal state placed further right exhibited greater cortisol synchrony than couples living in a federal state placed further left (b=0.01, p=.015). Findings point to the importance of considering the socio-political context of health-relevant biopsychosocial dynamics in old age. Future research needs to investigate mechanisms underlying such associations, including how politics shape opportunities and motivation for interdependencies that promote better or worse health.

    View details for DOI 10.1016/j.psyneuen.2020.105082

    View details for PubMedID 33316693

  • In-Person Contacts and Their Relationship With Alcohol Consumption Among Young Adults With Hazardous Drinking During a Pandemic. The Journal of adolescent health : official publication of the Society for Adolescent Medicine Suffoletto, B., Ram, N., Chung, T. 2020


    PURPOSE: Social distancing strategies such as "stay-at-home" (SAH) orders can slow the transmission of contagious viruses like the SARS-CoV-2 virus, but require population adherence to be effective. This study explored adherence to SAH orders by young adults with hazardous drinking, and the role of alcohol consumption with in-person contacts on adherence.METHODS: Analyses included young adults with hazardous drinking (i.e., AUDIT-C score ≥3/4 for women/men; n= 50; ages 18-25) participating in a randomized trial in Pittsburgh, PA. Participants provided experience sampling reports on drinking twice per week from the week before SAH orders started on April 1, 2020 through 6weeks during the SAH period. We examined how in-person contact with non-household friends changed over time and event-level relationships between alcohol consumption and in-person contacts.RESULTS: The percentage of participants with any in-person contact in the week before SAH was 44% (95% confidence interval [CI] 30%-59%), which decreased to 29% (95% CI 15%-43%) in the first SAH week and increased to 65% (95% CI 46%-85%) by SAH week 6. Controlling for average levels of alcohol consumption, on days when young adults drank, participants reported more in-person contacts compared to nondrinking days.CONCLUSIONS: Preliminary data indicate that, among young adults with hazardous drinking, adherence to public policies like SAH orders is suboptimal, declines over time, and is associated with drinking events. Interventions aimed at enhancing young adults' adherence to social distancing policies are urgently needed.

    View details for DOI 10.1016/j.jadohealth.2020.08.007

    View details for PubMedID 32943290

  • Discovering the Fabric of Supportive Conversations: A Typology of Speaking Turns and Their Contingencies JOURNAL OF LANGUAGE AND SOCIAL PSYCHOLOGY Bodie, G. D., Jones, S. M., Brinberg, M., Joyer, A. M., Solomon, D., Ram, N. 2020
  • Rollman and Brent: Phonotype. Journal of general internal medicine Robinson, T. N., Reeves, B., Ram, N. 2020

    View details for DOI 10.1007/s11606-020-05798-y

    View details for PubMedID 32221856

  • #Science: The potential and the challenges of utilizing social media and other electronic communication platforms in health care. Clinical and translational science Gijsen, V. n., Maddux, M. n., Lavertu, A. n., Gonzalez-Hernandez, G. n., Ram, N. n., Reeves, B. n., Robinson, T. n., Ziesenitz, V. n., Shakhnovich, V. n., Altman, R. n. 2019


    Electronic communication is becoming increasingly popular worldwide, as evidenced by its widespread and rapidly growing use. In medicine however, it remains a novel approach to reach out to patients. Yet, they have the potential for further improving current health care. Electronic platforms could support therapy adherence and communication between physicians and patients. The power of social media as well as other electronic devices can improve adherence as evidenced by the development of the app bant. Additionally, systemic analysis of social media content by Screenome can identify health events not always captured by regular health care. By better identifying these health care events we can improve our current health care system as we will be able to better tailor to the patients' needs. All these techniques are a valuable component of modern health care and will help us into the future of increasingly digital health care. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1111/cts.12687

    View details for PubMedID 31392837

  • Daily Actigraphy Profiles Distinguish Depressive and Interepisode States in Bipolar Disorder Clinical Psychological Science Gershon, A., Ram, N., Johnson, S. L., Harvey, A. G., Zeitzer, J. M. 2016; 4 (4): 641– 650


    Disruptions in activity are core features of mood states in bipolar disorder (BD). This study sought to identify activity patterns that discriminate between mood states in BD. Locomotor activity was collected using actigraphy for six weeks in participants with inter-episode BD type I (n=37) or participants with no lifetime mood disorders (n=39). The 24-hour activity pattern of each participant-day was characterized and within-person differences in activity patterns were examined across mood states. Results show that among participants with BD, depressive days are distinguished from other mood states by an overall lower activity level, and a pattern of later activity onset, a midday elevation of activity, and low evening activity. No distinct within-person activity patterns were found for hypomanic/manic days. Since activity can be monitored non-invasively for extended time periods, activity pattern identification may be leveraged to detect mood states in BD, thereby providing more immediate delivery of care.

    View details for DOI 10.1177/2167702615604613

    View details for PubMedCentralID PMC5022043