Elsevier

Journal of Psychiatric Research

Volume 81, October 2016, Pages 152-159
Journal of Psychiatric Research

Clinical significance of mobile health assessed sleep duration and variability in bipolar disorder

https://doi.org/10.1016/j.jpsychires.2016.07.008Get rights and content

Abstract

Objective

Sleep disturbances are prevalent, persistent, and impairing features of bipolar disorder. However, the near-term and cumulative impact of the severity and variability of sleep disturbances on symptoms and functioning remains unclear. We examined self-reported daily sleep duration and variability in relation to mood symptoms, medication adherence, cognitive functioning, and concurrent daily affect.

Methods

Forty-one outpatients diagnosed with bipolar disorder were asked to provide daily reports of sleep duration and affect collected via ecological momentary assessment with smartphones over eleven weeks. Measures of depressive and manic symptoms, medication adherence, and cognitive function were collected at baseline and concurrent assessment of affect were collected daily. Analyses examined whether sleep duration or variability were associated with baseline measures and changes in same-day or next-day affect.

Results

Greater sleep duration variability (but not average sleep duration) was associated with greater depressive and manic symptom severity, and lower medication adherence at baseline, and with lower and more variable ratings of positive affect and higher ratings of negative affect. Sleep durations shorter than 7–8 h were associated with lower same-day ratings of positive and higher same-day ratings of negative affect, however this did not extend to next-day affect.

Conclusions

Greater cumulative day-to-day sleep duration variability, but not average sleep duration, was related to more severe mood symptoms, lower self-reported medication adherence and higher levels of negative affect. Bouts of short- or long-duration sleep had transient impact on affect. Day-to-day sleep variability may be important to incorporate into clinical assessment of sleep disturbances in bipolar disorder.

Introduction

Disturbances in the quantity of sleep are common among patients diagnosed with bipolar disorder. Between 70 and 99% of bipolar patients experience a reduced need for sleep at some time during the course of their illness (Harvey et al., 2009). Many patients also report difficulties with falling asleep or staying asleep over the course of illness resulting in reduced or variable sleep duration. The influence of sleep duration on mood symptoms in bipolar disorder is complex—some studies show reduced and more variable sleep duration precede manic or depressive episodes (Barbini et al., 1996, Fava and Kellner, 1991, Gruber et al., 2011, Jackson et al., 2003, Perlman et al., 2006), and are evident during mood episodes (Cassidy et al., 1998), suggesting that abnormal sleep duration can be both a risk marker and a concomitant of bipolar episodes.

The majority of studies examining sleep in bipolar disorder have employed retrospective global measures of sleep duration collected over relatively short periods of observation. Some studies have employed prospective designs in which sleep and affect are measured concurrently over periods of one or several weeks (Bauer et al., 2006, Gershon et al., 2012, Gonzalez et al., 2014). These studies suggest that sleep and circadian disruptions are predictive of mood changes among people with bipolar disorder, which, in turn, has informed the basis of psychosocial interventions designed to stabilize sleep-wake patterns (Frank et al., 2005). Consistent with the idea that more variable sleep predicts more symptoms in bipolar disorder, Gruber et al. (2011) found in a sample of 196 remitted patients reporting on the maximum and minimum duration of sleep obtained in the previous week, that greater variability in sleep duration was associated with worsening of depression and mania across a one-year follow up period. Seemingly consistent with these data on individuals with bipolar disorder, among healthy individuals, reduced or more variable sleep duration over time is associated with a worsening of mood (Dinges et al., 1997), diminished well-being (Drake et al., 2001) and cognitive impairment (Boland and Alloy, 2013). Poor sleep has also been linked to lower medication adherence in individuals with serious medical conditions (Phillips et al., 2005), although no studies have examined this potential link, to our knowledge, in bipolar disorder. It remains unclear if between person differences in sleep duration variability are adequately captured in brief observation periods and across a range of levels of depressive and manic symptom severity. Additionally, more studies are needed to assess the dimensional components of bipolar disorder (Phillips and Kupfer, 2013). For example, depression has been characterized by low levels of positive affect, rather than high levels of negative affect (Dunn et al., 2004), whereas mania is characterized by high levels of positive affect or irritability, but not necessarily low levels of negative affect. Examining mood symptoms alone may obscure the subtleties of these affective dimensions in bipolar disorder.

Moreover, past studies have not yielded opportunities to examine proximal associations between sleep and mood. Sleep duration and variability has typically been evaluated with cross-sectional surveys (Goossens et al., 2010), and longitudinal studies with time points spaced months, or even years, apart (Gruber et al., 2011, Perlman et al., 2006, Saunders et al., 2015). Studies have employed actigraphy to measure sleep in bipolar patients, but sleep duration in these studies was only measured for one or two weeks (Harvey et al., 2005, Jones et al., 2005, Millar et al., 2004) and concurrent mood ratings were collected at one time point (Harvey et al., 2005, Jones et al., 2005) or by daily mood diary entries (Gershon et al., 2012, Millar et al., 2004). Mobile technology and ecological momentary assessment, the frequent real time and concurrent assessment of naturalistic behavior and affective experience, affords the ability to examine proximal associations between day-to-day sleep duration and variability and concurrent positive and negative affect. In addition, lagged models enable understanding of the potential carryover effects of impaired sleep on affect.

Data from a clinical trial in bipolar disorder with a comprehensive baseline characterization and 11-weeks of daily assessments of sleep and affect via smart phone surveys allowed us to more thoroughly examine the relationship of sleep duration and variability to symptom severity, medication adherence, global cognitive functioning, and longitudinally assessed positive and negative affect. We hypothesized lower average sleep duration would be positively correlated with baseline manic symptom severity and inversely correlated with baseline depressive symptom severity. We also predicted higher day-to-day variability in sleep duration would be associated with greater baseline manic and depressive symptom severity, lower medication adherence, and greater cognitive impairment. Finally, we hypothesized that day-to-day change in sleep duration and in how atypical the day’s sleep duration was compared to the person’s norm would predict increases in same-day and next-day negative affect and decreases in same-day and next-day positive affect.

Section snippets

Parent study

Data came from a randomized controlled trial of outpatients with bipolar I and II disorder in San Diego, which compared use of an automated mobile device-delivered intervention following brief psychoeducation with brief psychoeducation alone (Depp et al., 2015, Depp et al., 2012). Only subjects in the active arm (n = 41) were included. This study was carried out in accordance with the Declaration of Helsinki, and informed consent was obtained by all participants. The study was approved by the

Results

Demographic characteristics are displayed in Table 1. Participant ages were on average in the mid-to late-40s. Participants were balanced by sex, and the majority were white, few were married, and most were living independently in the community. The vast majority of participants were diagnosed with bipolar I (vs. II), and generally had an age of onset of bipolar disorder in the early 20s. Most participants were medicated.

Discussion

This study assessed how sleep duration and variability are related to mood symptoms, medication adherence, cognitive functioning and daily affect using ecological momentary assessment. We found greater person-averaged sleep variability was associated with greater depression and mania symptom severity and with lower self-reported medication adherence as measured at baseline, but not with global cognitive function. In other words, more severely symptomatic and less adherent patients reported more

Author contributions

Dr. Kaufmann wrote the manuscript and conducted statistical analyses. Dr. Gershon wrote the manuscript and provided feedback on statistical analyses. Dr. Eyler wrote the manuscript and provided feedback on statistical analyses. Dr. Depp wrote the manuscript, provided feedback on statistical analyses, and served as the parent study Principle Investigator. All authors have approved the final submitted article.

Conflicts of interest

None.

Role of funding sources

This study received funding from the National Institute of Mental Health (Grant #’s: T32MH019934, K23MH077225, R34MH091260, R01MH100417, K01MH100433, R01MH103318). The funding agencies listed did not have any role in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the article for publication.

Acknowledgement

None

References (44)

  • A. Millar et al.

    The sleep of remitted bipolar outpatients: a controlled naturalistic study using actigraphy

    J. Affect Disord.

    (2004)
  • T. Ohkuma et al.

    U-shaped association of sleep duration with metabolic syndrome and insulin resistance in patients with type 2 diabetes: the Fukuoka Diabetes Registry

    Metab. Clin. Exp.

    (2014)
  • M.L. Phillips et al.

    Bipolar disorder diagnosis: challenges and future directions

    Lancet

    (2013)
  • E.F.H. Saunders et al.

    The effect of poor sleep quality on mood outcome differs between men and women: a longitudinal study of bipolar disorder

    J. Affect Disord.

    (2015)
  • M. Bauer et al.

    Temporal relation between sleep and mood in patients with bipolar disorder

    Bipolar Disord.

    (2006)
  • F. Colom et al.

    Identifying and improving non-adherence in bipolar disorders

    Bipolar Disord.

    (2005)
  • S. Dallaspezia et al.

    Chronobiology of bipolar disorder: therapeutic implication

    Curr. Psychiatry Rep.

    (2015)
  • C.A. Depp et al.

    A pilot study of mood ratings captured by mobile phone versus paper-and-pencil mood charts in bipolar disorder

    J. Dual Diagn.

    (2012)
  • D.F. Dinges et al.

    Cumulative sleepiness, mood disturbance, and psychomotor vigilance performance decrements during a week of sleep restricted to 4-5 hours per night

    Sleep

    (1997)
  • C.L. Drake et al.

    Effects of rapid versus slow accumulation of eight hours of sleep loss

    Psychophysiology

    (2001)
  • B.D. Dunn et al.

    Categorical and dimensional reports of experienced affect to emotion-inducing pictures in depression

    J. Abnorm. Psychol.

    (2004)
  • G.A. Fava et al.

    Prodromal symptoms in affective disorders

    Am. J. Psychiatry

    (1991)
  • Cited by (0)

    View full text