Elsevier

Journal of Affective Disorders

Volume 210, 1 March 2017, Pages 280-286
Journal of Affective Disorders

Research paper
Residual depressive symptoms, sleep disturbance and perceived cognitive impairment as determinants of functioning in patients with bipolar disorder

https://doi.org/10.1016/j.jad.2016.12.054Get rights and content

Highlights

  • Residual symptoms have an impact on functioning in euthymic bipolar patients.

  • Residual depressive symptoms and cognitive performance directly affect functioning.

  • Sleep disturbances were indirectly associated with functioning.

  • Residual symptoms should be targeted in personalized treatment plans.

Abstract

Background

Many patients with bipolar disorder (BD) experience residual symptoms during their inter-episodic periods. The study aimed to analyse the relationship between residual depressive symptoms, sleep disturbances and self-reported cognitive impairment as determinants of psychosocial functioning in a large sample of euthymic BD patients.

Methods

This was a cross-sectional study of 468 euthymic BD outpatients. We evaluated the residual depressive symptoms with the Bipolar Depression Rating Scale, the sleep disturbances with the Pittsburgh Sleep Quality Index, the perceived cognitive performance using visual analogic scales and functioning with the Functioning Assessment Short Test. Structural equation modelling (SEM) was used to describe the relationships among the residual depressive symptoms, sleep disturbances, perceived cognitive performance and functioning.

Results

SEM showed good fit with normed chi square=2.46, comparative fit index=0.94, root mean square error of approximation=0.05 and standardized root mean square residuals=0.06. This model revealed that residual depressive symptoms (path coefficient =0.37) and perceived cognitive performance (path coefficient=0.27) were the most important features significantly related to psychosocial functioning. Sleep disturbances were indirectly associated with functioning via residual depressive symptoms and perceived cognitive performance (path coefficient=0.23).

Conclusions

This study contributes to a better understanding of the determinants of psychosocial functioning during the inter-episodic periods of BD patients. These findings should facilitate decision-making in therapeutics to improve the functional outcomes of BD during this period.

Introduction

Bipolar disorder (BD) is a severe and highly recurrent mental illness affecting more than one per cent of the world's population (Grande et al., 2016, Merikangas et al., 2011). A substantial proportion of BD patients (30–60%) are living with significant functional impairment even after reaching clinical remission (MacQueen et al., 2001). According to the World Health Organisation, BD is among the leading causes of years lost due to disability (WHO, 2008).

The inter-episode period (also named euthymia) was regarded as an asymptomatic phase in which BD patients were in clinical remission. However, this classical perspective has been challenged since a large number of euthymic patients experience residual symptoms during periods of apparent clinical stability (Soreca et al., 2009). New evidence suggests that BD is not only a recurrent mental illness but also a chronic disease associated with the persistence of residual symptoms shaping an individual presentation. Several studies have shown the persistence of depressive symptoms (Judd et al., 2003), cognitive impairments (Bourne et al., 2013, Mann-Wrobel et al., 2011), sleep and circadian rhythm disturbances (Geoffroy et al., 2014, Mondin et al., 2016, Sylvia et al., 2012) and emotional dysregulation (Strejilevich et al., 2013) in euthymic BD patients. Interestingly, residual symptoms appear to impact the natural course of BD and represent potential predictors of long-term outcome. Residual depressive symptoms are associated with an increased risk of recurrence (de Dios et al., 2012, Judd et al., 2008) and, together with persistent cognitive deficits and sleep disturbances, are important predictors of functional impairment (Altshuler et al., 2006, Bas et al., 2015, Baune and Malhi, 2015, Bonnín et al., 2010, Dittmann et al., 2008, Gitlin and Miklowitz, 2016, Harvey et al., 2005, Marangell et al., 2009, Pinho et al., 2015, Rosa et al., 2010, Wingo et al., 2009, Wingo et al., 2010).

Moreover, an interaction between those residual symptoms may exist—e.g. residual depressive symptoms seem to worsen cognitive deficits, producing a subsequent negative impact on functioning (Bonnín et al., 2014), or poor sleep and cognitive functioning seem to be associated with poor work performance (Boland et al., 2015). However, the exact nature of the interdependent relationships among residual depressive symptoms, cognitive impairment, sleep disturbances and functioning, and the relative contribution of each of these residual symptoms, remains unclear.

The observational OPTHYMUM study aimed to examine residual symptoms in BD patients who were recruited in the euthymic period. Previous analyses showed that residual symptoms (mainly residual depressive symptoms, perceived cognitive impairment and sleep disturbances) have an impact on functioning (Samalin et al., 2014, Samalin et al., 2016a) and their severity seems to be negatively related to the duration of the euthymia (Samalin et al., 2016b). However, these previous reports did not examine the direction and the structure of the relationships between residual symptoms and functioning. It would be of interest to contribute to a better understanding of the negative impact of these residual symptoms on the functioning of BD patients and it could have implications for its improvement.

Based on previous research (Boland and Alloy, 2013, Bonnín et al., 2012, Bonnín et al., 2014, Bowie et al., 2010, Giglio et al., 2010, Gruber et al., 2009, Leboyer and Kupfer, 2010, Rosa et al., 2013, Russo et al., 2015, Volkert et al., 2015), our hypotheses were that: i) residual depressive symptoms and perceived cognitive performance primarily have a direct effect on functioning; ii) sleep disturbances have an indirect effect on functioning via perceived cognitive performance and residual depressive symptoms; iii) residual depressive symptoms might have a moderate indirect effect on functioning via perceived cognitive performance; and iv) sleep disturbances might have a moderate direct effect on functioning.

The aim of the present study was to examine a comprehensive model based on structural equation modelling (SEM) that integrates the interrelationships between residual depressive symptoms, sleep disturbances and self-reported cognitive impairment as determinants of psychosocial functioning in a sample of euthymic BD patients in real-life conditions.

Section snippets

Study participants

This study is based on a sample of 468 adult outpatients with BD from a multi-centre, cross-sectional, non-interventional study conducted in France between April and October 2012 (Samalin et al., 2014).

An enlarged directory of psychiatrists randomly assigned from a previous French study on bipolar disorder was used (Nuss et al., 2012) to recruit a large number of patients. A total of 139 French psychiatrists in hospital and office-based settings agreed to participate to the study.

The inclusion

Sample characteristics

The sample consisted of 468 euthymic BD patients. Sociodemographic, clinical, functioning and therapeutic characteristics of the sample are presented in Table 1. Mean age was 47.7±12.5 years and 41% (n=192) were male. Mean age at onset of BD was 29.3±10.8 years, and most of the patients had a predominant depressive polarity of BD (56.6%).

Correlations

Correlations are provided in Table 2.

Residual depressive symptoms were moderately associated with all functioning domains except occupational functioning (r

Discussion

The present study investigated, through a SEM approach, the influence of residual depressive symptoms, perceived cognitive performance and sleep disturbances on psychosocial functioning among euthymic BD patients in real-life conditions. This is the first study to explore these three residual symptoms in the same model as determinants of functioning in BD. Our results highlight the non-straightforward relationship between sleep disturbances and functioning. The model showed good fit with the

Conclusion

This study highlights that residual depressive symptoms and perceived cognitive performance have a direct impact on the functioning of BD patients during the inter-episodic period. Sleep disturbances also seem to be associated with functional impairment, but only indirectly. The systematic assessment of residual symptoms based on easily administered questionnaires (e.g. self-evaluation of cognitive performance, sleep quality and sleep disturbance questionnaire) appears feasible and necessary in

Role of funding sources

This study was supported by Bristol-Myers Squibb France and Otsuka Pharmaceuticals France SAS. The funders had no further role in design study, data collection analysis and interpretation, writing of the report, and the decision to submit the paper for publication.

Contributors

PML and FB designed the study. LS, PML and FB performed the experiments. LB, LS and MB performed statistical analysis of results. LS, AM, FB, PML and EV wrote the first draft of the manuscript. All authors (LS, LB, AM, IP, MR, CMB, CT, NV, CP, IdC, MB, PAG, FB, PML, EV) contributed to and have approved the final manuscript.

Acknowledgements

We are greatly indebted to the many people who gave their time to participate in this study (Rosine Arnaud, Nabil Bedira, Anne Dillenschneider, Anne Filipovics, Pierre Vekoff and the investigators).

References (61)

  • P.A. Geoffroy et al.

    Sleep in remitted bipolar disorder: a naturalistic case-control study using actigraphy

    J. Affect. Disord.

    (2014)
  • L.M. Giglio et al.

    Functional impact of biological rhythm disturbance in bipolar disorder

    J. Psychiatry Res.

    (2010)
  • I. Grande et al.

    Bipolar disorder

    Lancet

    (2016)
  • J. Gruber et al.

    Sleep functioning in relation to mood, function, and quality of life at entry to the systematic treatment enhancement program for bipolar disorder (STEP-BD)

    J. Affect. Disord.

    (2009)
  • L.B. Marangell et al.

    The functional impact of subsyndromal depressive symptoms in bipolar disorder: data from STEP-BD

    J. Affect. Disord.

    (2009)
  • P. Nuss et al.

    Treatment practices in the management of patients with bipolar disorder in France. The TEMPPO study

    Encephale

    (2012)
  • M. Reinares et al.

    Towards a clinical staging for bipolar disorder: defining patient subtypes based on functional outcome

    J. Affect. Disord.

    (2013)
  • A.R. Rosa et al.

    Functional impairment and disability across mood states in bipolar disorder

    Value Health

    (2010)
  • M. Russo et al.

    The relationship between sleep quality and neurocognition in bipolar disorder

    J. Affect. Disord.

    (2015)
  • L. Samalin et al.

    Residual symptoms and functional performance in a large sample of euthymic bipolar patients in France (the OPTHYMUM study)

    J. Affect. Disord.

    (2014)
  • J. Volkert et al.

    Evidence for cognitive subgroups in bipolar disorder and the influence of subclinical depression and sleep disturbances

    Eur. Neuropsychopharmacol.

    (2015)
  • M.J. van der Werf-Eldering et al.

    Is the lack of association between cognitive complaints and objective cognitive functioning in patients with bipolar disorder moderated by depressive symptoms?

    J. Affect. Disord.

    (2011)
  • L.L. Altshuler et al.

    Subsyndromal depressive symptoms are associated with functional impairment in patients with bipolar disorder: Results of a large, multisite study

    J. Clin. Psychiatry

    (2006)
  • B.T. Baune et al.

    A review on the impact of cognitive dysfunction on social, occupational, and general functional outcomes in bipolar disorder

    Bipolar Disord.

    (2015)
  • M. Berk et al.

    The bipolar depression Rating scale (BDRS): its development, validation and utility

    Bipolar Disord.

    (2007)
  • C.M. Bonnin et al.

    Functional remediation in bipolar disorder: 1-year follow-up of neurocognitive and functional outcome

    Br. J. Psychiatry

    (2016)
  • C. Bourne et al.

    Neuropsychological testing of cognitive impairment in euthymic bipolar disorder: an individual patient data meta-analysis

    Acta Psychiatr. Scand.

    (2013)
  • C.R. Bowie et al.

    Prediction of real-world functional disability in chronic mental disorders: a comparison of schizophrenia and bipolar disorder

    Am. J. Psychiatry

    (2010)
  • D. Claire et al.

    Validation of the french version of the functioning assessment short test (FAST) in patients with bipolar disorder. A study from the french bipolar expert centers network

    Int. Clin. Psychopharmacol.

    (2012)
  • J. Cohen

    Statistical Power Analysis for Behavioural Sciences

    (1988)
  • Cited by (47)

    • The relationship between morningness-eveningness and mood symptoms and quality of life in euthymic state of mood disorders: Results from a prospective observational cohort study

      2022, Journal of Affective Disorders
      Citation Excerpt :

      Furthermore, evening preference was related to higher disruption in biological rhythms, and bipolar disorder and major depressive disorder patients had higher biological rhythm disruption, even on periods of euthymia, compared to healthy controls (Mondin et al., 2017). Although most distinctly characterized by recurrent mood episodes, recurrent major depressive disorder and bipolar disorder are becoming to be understood as chronic diseases with persisting residual symptoms during inter-episode periods (Samalin et al., 2017). Residual symptoms are considered to be responsible for lower overall psychosocial functioning of euthymic patients with bipolar disorder (Samalin et al., 2016).

    • Residual symptoms in bipolar disorders: Findings from the bipolar Disorder course and outcome study from India (BiD-CoIN study)

      2021, Psychiatry Research
      Citation Excerpt :

      Besides the number and duration of episodes, residual symptoms in BD impair social, occupational, and cognitive functioning(Altshuler et al., 2006; Marangell, 2004; L Samalin et al., 2016; Samalin et al., 2017). The presence of residual depressive symptoms are associated with a shorter time to recurrence of a depressive episode(Meyer, 2006; Perlis et al., 2006), poor functioning(Altshuler et al., 2006; Marangell, 2004; L Samalin et al., 2016; Samalin et al., 2017) and poor medication adherence(Belzeaux et al., 2013). Residual manic symptoms are associated with shorter time to manic, hypomanic, or mixed recurrences (Meyer, 2006; Perlis et al., 2006), financial problems, family stigma, poor interpersonal relationships, sexual dysfunction, and occupational stigma (Samalin et al., 2016).

    View all citing articles on Scopus
    View full text