Sleep and depression--results from psychobiological studies: an overview

Impact of number of sleep ultradian cycles on polysomnographic parameters related to REM sleep in major depression: Implications for future sleep research in psychiatry

Given the contradictory data on REMS alterations in major depression, the aim of this study was to empirically demonstrate that based on the number of sleep ultradian cycles, it was possible to highlight different subtypes of major depression characterized by specific patterns of REMS alterations. Demographic and polysomnographic data from 211 individuals (30 healthy controls and 181 untreated major depressed individuals) recruited from the sleep laboratory database were analyzed. Major depressed individuals with sleep ultradian cycles <4 showed alterations consistent with REMS deficiency (non-shortened REM latency as well as decrease in REMS percentage, REMS duration and REMS/NREMS ratio) whereas major depressed individuals with sleep ultradian cycles >4 showed alterations consistent with REMS disinhibition (shortened REM latency as well as increase in REMS percentage, REMS duration and REMS/NREMS ratio). Regarding major depressed individuals with 4 sleep ultradian cycles, their REMS alterations were intermediate to those present in major depressed individuals with sleep ultradian cycles <4 and >4. Thus, in major depressed individuals, the highlighting of this heterogeneity of REMS alterations based on the number of sleep ultradian cycles seems to suggest the involvement of distinct pathophysiological mechanisms and could open new perspectives for future sleep research in psychiatry.

Sleep, insomnia, and depression

Since ancient times it is known that melancholia and sleep disturbances co-occur. The introduction of polysomnography into psychiatric research confirmed a disturbance of sleep continuity in patients with depression, revealing not only a decrease in Slow Wave Sleep, but also a disinhibition of REM (rapid eye movement) sleep, demonstrated as a shortening of REM latency, an increase of REM density, as well as total REM sleep time. Initial hopes that these abnormalities of REM sleep may serve as differential-diagnostic markers for subtypes of depression were not fulfilled. Almost all antidepressant agents suppress REM sleep and a time-and-dose-response relationship between total REM sleep suppression and therapeutic response to treatment seemed apparent. The so-called Cholinergic REM Induction Test revealed that REM sleep abnormalities can be mimicked by administration of cholinomimetic agents. Another important research avenue is the study of chrono-medical timing of sleep deprivation and light exposure for their positive effects on mood in depression. Present day research takes the view on insomnia, i.e., prolonged sleep latency, problems to maintain sleep, and early morning awakening, as a transdiagnostic symptom for many mental disorders, being most closely related to depression. Studying insomnia from different angles as a transdiagnostic phenotype has opened many new perspectives for research into mechanisms but also for clinical practice. Thus, the question is: can the early and adequate treatment of insomnia prevent depression? This article will link current understanding about sleep regulatory mechanisms with knowledge about changes in physiology due to depression. The review aims to draw the attention to current and future strategies in research and clinical practice to the benefits of sleep and depression therapeutics.

Prevalence and correlates of depressive symptoms in secondary school children in Dhaka city, Bangladesh

Objectives: Depression is a leading contributor to the global burden of disease, and often starts at a young age. Depression in young people can increase the risk of unhealthy lifestyle behaviour and can lead to substantial disability, social problems, poor health, and suicide. Other research has examined depressive symptoms among adult populations in Bangladesh, but little is known about other age groups. The aim of this study was to assess the prevalence and socio-demographic correlates of depressive symptoms among secondary school children of Dhaka city, Bangladesh.Design: A self-completed questionnaire was administered to 898 students from eight secondary schools of Dhaka, the capital City of Bangladesh. Of the respondents, 755 (372 males, 383 females; average age 14.26 years; SD 1.15) completed the 10-item Center for Epidemiological Studies Depression Scale (CESD-10). A score of 10 or more was used to indicate depressive symptoms. Parents completed a separate questionnaire to provide individual and household/family-level data. Generalized Estimating Equations (GEE) was used to assess sociodemographic and lifestyle factors associated with adolescent depressive symptoms.Results: Among the responding adolescents, 25% reported depressive symptoms with prevalence more common among females than males (30% vs. 19%). Factors significantly associated with symptoms of depression included being female, aged 15-16 years, self-perception of non-normal weight, feeling unsafe at school, sleep disturbance, low life satisfaction, high intake of sugary drinks, and regularly skipping breakfast.Conclusion: Depressive symptoms are prevalent among secondary school children in urban Bangladesh. Interventions for adolescents with depressive symptoms could focus on lifestyle practices such as weight management, personal safety, sleep hygiene and healthy eating.

Sleep quality and cognitive impairment in older Chinese: Guangzhou Biobank Cohort Study

BACKGROUND

evidence concerning the relationship between sleep quality and cognitive impairment is limited and inconsistent.

OBJECTIVE

to examine the association of sleep quality with memory impairment and poor cognitive function in a large sample of older Chinese.

METHODS

15,246 participants aged 50+ years of the Guangzhou Biobank Cohort Study who attended the second physical examination from 2008 to 2012 were included. Sleep quality was assessed using Pittsburgh Sleep Quality Index (PSQI), and cognitive performance was assessed using both Delayed Word Recall Test (DWRT) and Mini-Mental State Examination (MMSE). Memory impairment was defined by DWRT score < 4 and poor cognitive function by MMSE score < 25.

RESULTS

after adjusting for potential confounders, lower habitual sleep efficiency was associated with a higher risk of memory impairment and poor cognitive function with a dose-response pattern (both P for trend <0.001). The adjusted odds ratio (OR, 95% confidence interval (CI)) for poor cognitive function in those with the sleep efficiency of 75-85%, 65-75% and <65%, versus ≥85%, was 1.31 (1.12-1.53), 1.41 (1.16-1.73) and 1.33 (1.09-1.63), respectively. No association of the global PSQI score with memory impairment or poor cognitive function was found.

CONCLUSIONS

in older Chinese people, lower habitual sleep efficiency was associated with a higher risk of memory impairment and poorer cognitive function.

Sleep Disorders in Rodent Models of Parkinson's Disease

Sleep disorders are frequently diagnosed in Parkinson's disease and manifested in the prodromal and advanced stages of the disease. These conditions, which in some cases affect more than 50% of Parkinson's disease (PD) patients, include hypersomnia, often manifested as excessive daytime sleepiness, insomnia, characterized by delayed initiation and fragmentation of sleep at night, and disruption of rapid eye movement (REM) sleep, resulting in loss of atonia and dream enactment. Standard dopamine replacement therapies for the treatment of motor symptoms are generally inadequate to combat sleep abnormalities, which seriously affect the quality of life of PD patients. Rodent models still represent a major tool for the study of many aspects of PD. They have been primarily designed to eliminate midbrain dopamine neurons and elicit motor impairment, which are the traditional pathological features of PD. However, rodent models are increasingly employed to investigate non-motor symptoms, which are often caused by degenerative processes affecting multiple monoaminergic and peptidergic structures. This review describes how neurotoxic and genetic manipulations of rats and mice have been utilized to reproduce some of the major sleep disturbances associated with PD and to what extent these abnormalities can be linked to nondopaminergic dysfunction, affecting for instance noradrenaline, serotonin, and orexin transmission. Strengths and limitations are discussed, as well as the consistency of results obtained so far, and the need for models that better reproduce the multisystemic neurodegenerative nature of PD, thereby allowing to replicate the complex etiology of sleep-related disorders.

Contributions of the Women's Health Initiative to understanding associations between sleep duration, insomnia symptoms, and sleep-disordered breathing across a range of health outcomes in postmenopausal women

The Women's Health Initiative (WHI), a longitudinal study of more than 161,000 postmenopausal women across the United States, provides an opportunity to investigate the link between sleep health and healthy aging. The purpose of this paper was to systematically review all published WHI articles examining sleep as a predictor of health outcomes and health behaviors/quality of life outcomes. A strength of the WHI is that for most participants, sleep measures were completed before a major health diagnosis, with a significant portion of participants also providing sleep measures after diagnosis. Twenty-three WHI articles were identified and examined for this review. The combination of sleep duration and insomnia symptoms was the most commonly investigated sleep measure. The results indicated that both short (≤6 hours) and long (≥9 hours) sleep duration were associated with a higher risk of cardiovascular disease, colorectal cancer, mortality, cognitive decline, and poor diet. Insomnia symptoms, frequent snoring, and risk of sleep-disordered breathing (SDB) were also associated with increased risk for ischemic stroke and cardiovascular disease. However, many significant results were attenuated after multivariable adjustment. Limitations of these WHI examinations include the use of different categories for sleep measures across studies and a lack of examination by race/ethnicity. Owing to the longitudinal study design, large sample size, and long-term follow-up for health outcomes, the WHI serves as a rich resource for examining associations between sleep characteristics, demographics, and health in postmenopausal women.

Alterations of neural network organisation during rapid eye movement sleep and slow-wave sleep in major depression: Implications for diagnosis, classification, and treatment

The aim of this study was to empirically investigate the network organisation during rapid eye movement sleep (REMS) and slow-wave sleep (SWS) using the effective connectivity measured using the Granger causality to identify new potential biomarkers for the diagnosis, classification, and potential favourable response to treatment in major depression. Polysomnographic data were analysed from 24 healthy individuals and 16 major depressed individuals recruited prospectively. To obtain the 19×19 connectivity matrix of all possible pairwise combinations of electrodes by the Granger causality method from our electroencephalographic data, we used the Toolbox MVGC multivariate Granger causality. The computation of network measures was realised by importing these connectivity matrices into the EEGNET Toolbox. Major depressed individuals (versus healthy individuals) and those with endogenous depression (versus those with neurotic depression) present alterations of small-world network organisation during REMS, whereas major depressed individuals with potential favourable response to electroconvulsive therapy (versus those with potential unfavourable response) have a less efficient small-world network organisation during SWS. Thus, alterations in network organisation during REMS could be biomarkers for the diagnosis and classification of major depressive episodes, whereas alterations of network organisation during SWS could be a biomarker to predict potential favourable response to treatment by electroconvulsive therapy.

Sleep problems and depression among 237 023 community-dwelling adults in 46 low- and middle-income countries

Sleep problems are considered a core symptom of depression. However, there is little information about the comorbidity of sleep problems and depression in low- and middle-income countries (LMICs), and whether sleep problems with depression confer additional risk for decrements in health compared to sleep problems alone. This study thus examined the association between sleep problems and depression and whether sleep problems with depression are associated with an increased risk for poorer health in 46 LMICs. Cross-sectional, community-based data from 237 023 adults aged ≥18 years from the World Health Survey (WHS) 2002–2004 were analyzed. Information on sleep problems (severe/extreme) and International Classification of Diseases 10th Revision depression/depression subtypes was collected. Multivariable logistic (binary and multinomial) and linear regression analyses were performed. Sleep problems were associated with subsyndromal depression (odds ratio [OR]: 2.23, 95% confidence interval [CI]: 1.84–2.70), brief depressive episode (OR = 2.48, 95% CI = 2.09–2.95) and depressive episode (OR = 3.61, 95% CI = 3.24–4.03). Sleep problems with depression (vs. sleep problems alone) conferred additional risk for anxiety, perceived stress and decrements in health in the domains of mobility, self-care, pain, cognition, and interpersonal activities. Clinicians should be aware that the co-occurrence of sleep problems and depression is associated with a variety of adverse health outcomes in LMICs. Detecting this co-occurrence may be important for treatment planning.

[Sleep disorders as one of the indicators of postpartum depression]

Postpartum depression in ICD-10 refers to mild mental and behavioral disorders associated with physiological disorders of the postpartum period F53.0. Diagnosis is based on criteria, one of which is sleep disorders. The objective of the review is to characterize the postpartum sleep disorders and to reflect their predictor value in the development of postpartum depression. Presomnic, intrasomnic and postsomnic disorders with negative consequences for both the mother and her child were found in sleep disorders of women with postpartum depression. Depression with sleep disorders significantly affect the quality of life of the mother and infant. Sleep disorders are one of the predictors of postpartum depression. Improving of sleep quality is an effective way to prevent the effects of postpartum depression.

Sleep restriction caused impaired emotional regulation without detectable brain activation changes-a functional magnetic resonance imaging study

Sleep restriction has been proposed to cause impaired emotional processing and emotional regulation by inhibiting top-down control from prefrontal cortex to amygdala. Intentional emotional regulation after sleep restriction has, however, never been studied using brain imaging. We aimed here to investigate the effect of partial sleep restriction on emotional regulation through cognitive reappraisal. Forty-seven young (age 20-30) and 33 older (age 65-75) participants (38/23 with complete data and successful sleep intervention) performed a cognitive reappraisal task during fMRI after a night of normal sleep and after restricted sleep (3 h). Emotional downregulation was associated with significantly increased activity in the dorsolateral prefrontal cortex (p _FWE < 0.05) and lateral orbital cortex (p _FWE < 0.05) in young, but not in older subjects. Sleep restriction was associated with a decrease in self-reported regulation success to negative stimuli (p < 0.01) and a trend towards perceiving all stimuli as less negative (p = 0.07) in young participants. No effects of sleep restriction on brain activity nor connectivity were found in either age group. In conclusion, our data do not support the idea of a prefrontal-amygdala disconnect after sleep restriction, and neural mechanisms underlying behavioural effects on emotional regulation after insufficient sleep require further investigation.

REM sleep fragmentation associated with depressive symptoms and genetic risk for depression in a community-based sample of adolescents

INTRODUCTION

Fragmented REM sleep may impede overnight resolution of distress and increase depressive symptoms. Furthermore, both fragmented REM and depressive symptoms may share a common genetic factor. We explored the associations between REM sleep fragmentation, depressive symptoms, and a polygenic risk score (PRS) for depression among adolescents.

METHODS

About 161 adolescents (mean age 16.9 ± 0.1 years) from a birth cohort underwent a sleep EEG and completed the Beck Depression Inventory-II the same day. We calculated PRSes for depressive symptoms with PRSice 1.25 software using weights from a recent genome-wide association study for dimensions of depressive symptoms (negative emotion, lack of positive emotion and somatic complaints). REM fragmentation in relation to entire REM duration was manually calculated from all REM epochs. REM latency and density were derived using SomnoMedics DOMINO software.

RESULTS

PRSes for somatic complaints and lack of positive emotions were associated with higher REM fragmentation percent. A higher level of depressive symptoms was associated with increased percent of REM fragmentation and higher REM density, independently of the genetic risks. Belonging to the highest decile in depressive symptoms was associated with a 2.9- and 7.6-fold risk of belonging to the highest tertile in REM fragmentation and density. In addition, higher PRS for somatic complaints had an independent, additive effect on increased REM fragmentation.

LIMITATION

A single night's sleep EEG was measured, thus the night-to-night stability of the REM fragmentation-depressive symptom link is unclear.

CONCLUSION

Depressive symptoms and genetic risk score for somatic complaints are independently associated with more fragmented REM sleep. This offers new insights on the quality of sleep and its relation to adolescents' mood.

Strained Bedfellows: An Actor-Partner Analysis of Spousal Attachment Insecurity and Sleep Quality

Background

The quality of interpersonal ties-especially closer relationships-appears to be associated with physical health outcomes. Sleep is one pathway through which relationships and health appear to be linked, but this has been inadequately investigated in the context of dyadic attachment.

Purpose

The present study examined links between relationship-specific attachment anxiety (which can involve preoccupation with one's partner, negative relationship cognitions, and fear of abandonment) and avoidance (e.g., low emotional investment or intimacy) and sleep quality.

Methods

Attachment, assessed using the Experience in Close Relationship (ECR), was used to predict Pittsburgh Sleep Quality Inventory (PSQI)-assessed sleep quality in 92 married heterosexual couples via actor-partner interdependence models. Depression was examined as a potential mediator of this association.

Results

Consistent with hypotheses, actors' anxious attachment predicted diminished quality of their own sleep, whereas actors' avoidant attachment was unrelated to their own sleep quality. Results further suggested that couples in which both spouses were higher in attachment anxiety experience better sleep quality (b = -0.74, SE = 0.28, p = .0082, 95% CI [-1.287, -0.196]). Conversely, couples in which both spouses were higher in attachment avoidance showed poorer sleep quality (b = 0.56, SE = 0.23, p = .0188, 95% CI [0.095, 1.016]). These effects were found to be independent of marital satisfaction and depression. Some evidence was also consistent with mediation of links between attachment and sleep quality via depression.

Conclusions

Results suggest adult romantic attachment and sleep are associated in complex ways, highlighting the importance of dyadic approaches to the study of relationships, sleep, and health.

The Relationship Between Global Sleep Score And Inflammatory Markers In Obese Adults From The United States

BACKGROUND

Poor sleep is a risk factor for cardiovascular diseases (CVDs). The underlying pathogenesis is not clear. Levels of inflammatory markers, such as C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-ɑ (TNF-ɑ), have been found to be elevated in patients with CVDs.

AIM

The study aimed to investigate the associations between sleep quality and serum inflammatory markers in a cohort of obese adults.

METHODS

This was a second analysis of the data from the Midlife in the United States (MIDUS) study, a longitudinal study of a national (US) sample of adults. A total of 1255 participants completed comprehensive biological assessments. The associations between global sleep score and serum levels of inflammatory markers were analyzed.

RESULTS

Univariate analysis showed that a higher global sleep score was correlated with lower age (r = -0.079, P= 0.009), higher BMI (r = 0.100, P= 0.001) and heavier perceived stress (r = 0.335, P<0.001). Multivariate linear regression analysis showed that the global sleep score was positively related to levels of IL-6 (Sβ=0.074, P=0.009), IL-8 (Sβ=0.089, P=0.002), TNF-ɑ (Sβ=0.0.082, P=0.005), E-selectin (Sβ=0.071, P=0.016) and intercellular adhesion molecule-1 (ICAM-1, Sβ=0.117, P<0.001) after adjustments were made for age, gender, race, marital status, education, current smoking status, physician-diagnosed CVDs and respiratory diseases, BMI and perceived stress. However, the global sleep score was not associated with serum IL-10 (Sβ=-0.021, P=0.463) and CRP (Sβ=0.035, P=0.059) levels after adjustments were made for these confounding factors.

CONCLUSION

Poor sleep is positively associated with serum inflammatory marker levels among obese adults. Sufficient sleep may be particularly important for obese adults to prevent CVDs.

A longitudinal analysis of the relationships among daytime dysfunction, fatigue, and depression in college students

OBJECTIVE

To examine the longitudinal trajectory of daytime dysfunction (DD) and its relationship with fatigue by depression status in university students.

PARTICIPANTS

243 students completed online surveys from September- December 2016.

METHODS

Surveys were conducted at three time points over a semester period: the beginning of the semester, the end of mid-term and the end of the semester.

RESULTS

Results indicated that the DD significantly increased in all students over the semester. Students with depression showed a higher initial level of DD and faster rate of change compared to those without depression. A faster rate of change of DD predicted a higher level of end-semester fatigue.

CONCLUSIONS

Depression is related to a higher initial level of DD and its faster rate change which in turn, predicted end-semester fatigue, identifying one of the possible pathways through which depression impacts the functioning and health of affected students.

Night-time rumination in PTSD: development and validation of a brief measure

Background: Pre-sleep cognitive activity and arousal have long been implicated in the maintenance of insomnia. However, despite high comorbidity between insomnia and posttraumatic stress disorder (PTSD), pre-sleep thoughts in PTSD and their associations with disturbed sleep, have not yet been investigated. Objective: This study presents the development and preliminary validation of a brief self-report measure of the content of trauma-related pre-sleep thoughts: the Trauma Thoughts before Sleep Inventory (TTSI). Methods: Participants (N = 285) were recruited online into five groups: three groups with clinical symptoms, 1) PTSD; 2) depression without PTSD; 3) insomnia without depression or PTSD; and two healthy control groups 4) nontrauma-exposed controls; 5) trauma-exposed controls. The questionnaire was administered at baseline, and for a subsample (n = 157) again one week later to assess test-retest reliability. At baseline, participants also completed questionnaires of sleep quality, PTSD and depression symptoms, and insomnia-related thoughts. Results: The TTSI had good reliability and validity; it discriminated participants with PTSD from those with depression and insomnia, those with depression from insomnia, and correlated with existing measures of pre-sleep thoughts, self-reported pre-sleep arousal and poor sleep. Conclusions: The results support the utility of the TTSI for measuring thoughts that keep people with PTSD awake, although replication in an independent clinical sample is required.

Religion, Combat Casualty Exposure, and Sleep Disturbance in the US Military

Does religious involvement (i.e., attendance and salience) mitigate the association between combat casualty exposure and sleep disturbance among US military veterans? To address this question, we analyze cross-sectional survey data from the public-use version of the 2011 Health Related Behaviors Survey of Active Military Personnel. Results from multivariate regression models indicate: (1) Combat casualty exposure was positively associated with sleep disturbance; (2) religious salience both offset and moderated (i.e., buffered) the above association; and (3) religious attendance offset but did not moderate the above association. We discuss study implications and limitations, as well as some avenues for future research.

The role of inflammation in core features of depression: Insights from paradigms using exogenously-induced inflammation

A wealth of evidence has implicated inflammation in the development of depression. Yet, the heterogeneous nature of depression has impeded efforts to understand, prevent, and treat the disease. The purpose of this integrative review is to summarize the connections between inflammation and established core features of depression that exhibit more homogeneity than the syndrome itself: exaggerated reactivity to negative information, altered reward processing, decreased cognitive control, and somatic syndrome. For each core feature, we first provide a brief overview of its relevance to depression and neurobiological underpinnings, and then review evidence investigating a potential role of inflammation. We focus primarily on findings from experimental paradigms of exogenously-induced inflammation. We conclude that inflammation likely plays a role in exaggerated reactivity to negative information, altered reward reactivity, and somatic symptoms. There is less evidence supporting an effect of inflammation on cognitive control as assessed by standard neuropsychological measures. Finally, we discuss implications for future research and recommendationsfor how to test the role of inflammation in the pathogenesis of heterogeneous psychiatric disorders.

Moderating effects of depressive symptoms on the relationship between problematic use of the Internet and sleep problems in Korean adolescents

BACKGROUND

Adolescence is a period of marked sleep pattern changes and sleep problems, which may result from both endogenous and exogenous factors. Among the various factors affecting adolescent sleep, depression and problematic Internet use (PIU) have received considerable attention. We examined if there is a different PIU effect on sleep between depressed group and non-depressed groups.

METHODS

Data for a total of 766 students' between 7th and 11th grades were analyzed. We assessed various variables related sleep to problems and depression and compared those variables between an adolescent group with problematic Internet use (PIUG) and an adolescent group with normal Internet use (NIUG).

RESULTS

One hundred fifty two participants were classified as PIUG, and 614 were classified as NIUG. Compared with the NIUG, the members of the PIUG were more prone to insomnia, excessive daytime sleepiness and sleep-wake behavior problems. The PIUG also tended to include more evening types than the NIUG. Interestingly, the effect of Internet use problems on sleep problems appeared to be different according to the presence or absence of the moderating effect of depression. When we considered the moderating effect of depression, the effect of Internet use problems on sleep-wake behavior problems, insomnia and excessive daytime sleepiness increased with increasing Young's Internet Addiction Scale (IAS) scores in the non-depressed group. However, in the depressed group, the effects of Internet use problems on sleep-wake behavior problems and insomnia did not change with increasing Internet use problems, and the effect of Internet use problems on excessive daytime sleepiness was relatively decreased with increasing Internet use problems in the depressed group.

CONCLUSIONS

This study demonstrated that the effect of PIU on sleep presented differently between the depressed and non-depressed groups. PIU is associated with poorer sleep in non-depressed adolescents but not in depressed adolescents. This finding might be observed because PIU may be the biggest contributor to sleep problems in the problematic Internet user without depression, but in the problematic Internet user with depression, depression might be a more important contributor to sleep problems; thus, the influence of PIU on sleep effect might be diluted.

Heterogeneity of sleep quality in relation to circadian preferences and depressive symptomatology among major depressive patients

BACKGROUND

The current study aimed at investigating the latent dimensional structure of sleep quality as indexed by the seven components of the Pittsburgh Sleep Quality Index (PSQI), as well as latent covariance structure between sleep quality, circadian preferences and depressive symptoms.

METHODS

Two hundred twenty-five patients with major depressive disorder (MDD), with an average age of 29.92 ± 10.49 years (aged between 17 and 63), participated in the study. The PSQI, Morningness-Eveningness Questionnaire (MEQ) and Beck Depression Inventory (BDI) were administered to participants. Four sets of latent class analyses were subsequently run to obtain optimal number of latent classes best fit to the data.

RESULTS

Mixture models revealed that sleep quality is multifaceted in MDD. The data best fit to four-latent-class model: Poor Habitual Sleep Quality (PHSQ), Poor Subjective Sleep Quality (PSSQ), Intermediate Sleep Quality (ISQ), and Good Sleep Quality (GSQ). MDD patients classified into GSQ latent class (23.6%) reported the lowest depressive symptoms and were more prone to morningness diurnal preferences compared to other three homogenous sub-groups. Finally, the significant association between eveningness diurnal preferences and depressive symptomatology was significantly mediated by poor sleep quality.

LIMITATION

The cross-sectional nature of the study and the lack of an objective measurement of sleep such as polysomnography recordings was the most striking limitation of the study.

CONCLUSIONS

We concluded sleep quality in relation to circadian preferences and depressive symptoms has a heterogeneous nature in MDD.

Research into an Association between Anhedonia and Decreased REM Latency in Moderately to Severely Depressed Patients

Anhedonia stands as a core symptom and potential trait marker of major depressive disorder (MDD). The importance of rapid eye movement sleep latency (REML) as a biological marker of depression has previously and repeatedly been studied. The aim of this paper is to analyse the relationship between anhedonia and REML in moderately to severely depressed patients. The shortened Beck Depression Inventory (BDI-13) was chosen to assess depressive symptoms and, among them, more particularly, anhedonic symptoms. Two-way ANCOVA was used for statistical analyses. A significant association between anhedonic symptoms and REML was found when the number of sleep cycles (NCy) and the severity of depression were added as covariates. Our findings suggest that REML may be a useful variable to differentiate some diagnostic subtypes of depression related to anhedonia.

Diffusion Tensor Imaging (DTI) Correlates of Self-Reported Sleep Quality and Depression Following Mild Traumatic Brain Injury

Background: Mild traumatic brain injuries (mTBIs) are a significant social, sport, and military health issue. In spite of advances in the clinical management of these injuries, the underlying pathophysiology is not well-understood. There is a critical need to advance objective biomarkers, allowing the identification and tracking of the long-term evolution of changes resulting from mTBI. Diffusion-weighted imaging (DWI) allows for the assessment of white-matter properties in the brain and shows promise as a suitable biomarker of mTBI pathophysiology. Methods: 34 individuals within a year of an mTBI (age: 24.4 ± 7.4) and 18 individuals with no history of mTBI (age: 23.2 ± 3.4) participated in this study. Participants completed self-report measures related to functional outcomes, psychological health, post-injury symptoms, and sleep, and underwent a neuroimaging session that included DWI. Whole-brain white matter was skeletonized using tract-based spatial statistics (TBSS) and compared between groups as well as correlated within-group with the self-report measures. Results: There were no statistically significant anatomical differences between the two groups. After controlling for time since injury, fractional anisotropy (FA) demonstrated a negative correlation with sleep quality scores (higher FA was associated with better sleep quality) and increasing depressive symptoms in the mTBI participants. Conversely, mean (MD) and radial diffusivity (RD) demonstrated positive correlations with sleep quality scores (higher RD was associated with worse sleep quality) and increasing depressive symptoms. These correlations were observed bilaterally in the internal capsule (anterior and posterior limbs), corona radiata (anterior and superior), fornix, and superior fronto-occipital fasciculi. Conclusion: The results of this study indicate that the clinical presentation of mTBI, particularly with respect to depression and sleep, is associated with reduced white-matter integrity in multiple areas of the brain, even after controlling for time since injury. These areas are generally associated not only with sleep and emotion regulation but also cognition. Consequently, the onset of depression and sleep dysfunction as well as cognitive impairments following mTBI may be closely related to each other and to white-matter integrity throughout the brain.

Mechanisms underlying the association between insomnia, anxiety, and depression in adolescence: Implications for behavioral sleep interventions

There is robust evidence of an association between insomnia, anxiety, and depression in adolescence. The aim of this review is to describe and synthesize potential mechanisms underlying this association and explore implications for the design of adolescent behavioral sleep interventions. Specifically, we examine whether insomnia symptoms are a mechanism for the development of internalizing symptoms in adolescence and whether sleep interventions are an effective treatment for both insomnia and internalizing symptoms in adolescence because they target the shared mechanisms underlying these disorders. Research using different methodologies points to the role of sequential, parallel, and interacting mechanisms. In this paper, we review a wide range of relevant biological (i.e., polymorphisms and dysregulation in serotonin, dopamine, and circadian clock genes; alterations in corticolimbic and mesolimbic brain circuits; cortisol reactivity to stress; inflammatory cytokine dysregulation; biased memory consolidation; changes in sleep architecture), psychological (i.e., cognitive inflexibility, interpretational biases, judgment biases, negative attribution styles, worry, rumination, biased attention to threat, dysfunctional beliefs and attitudes about sleep, misperception of sleep deficit), and social mechanisms (i.e., reduced and impaired social interactions, unhelpful parenting behaviors, family stress) and propose an integrative multilevel model of how these phenomena may interact to increase vulnerability to both insomnia and internalizing disorders. Several 'biopsychosocial' mechanisms hold promise as viable treatment targets for adolescent behavioral sleep interventions, which may reduce both insomnia and internalizing symptoms.

Schizotypal traits are associated with sleep spindles and rapid eye movement in adolescence

Research suggests an association between schizophrenia and a decrease in sleep spindle activity, as well as a change in sleep architecture. It is unknown how the continuum of psychotic symptoms relates to different features in the sleep electroencephalogram. We set out to examine how sleep architecture and stage 2 spindle activity are associated with schizotypy in a healthy adolescent population. The participants in our study (n = 176, 61% girls) came from a community-based cohort. Schizotypal traits were evaluated using the Schizotypal Personality Scale (STA) in early adolescence (mean age 12.3 years, SD = 0.5) and the participants underwent ambulatory overnight polysomnography at mean age 16.9 years (SD = 0.1). Sleep was scored in 30-s epochs into stages 1, 2, 3 and rapid eye movement (REM) sleep. Stage 2 spindles were detected using an automated algorithm. Spindle analyses from central and frontal derivations included spindle duration and density for slow (10-13 Hz) and fast (13-16 Hz) ranges. Covariates included sex and age. Those with the highest STA scores had a higher percentage of REM (B = 2.07 [95% CI, 0.17, 4.0]; p = .03) than those with the lowest scores. Those with the highest scores had shorter spindle duration, as derived from the frontal regions, and a slower oscillation range (B = -0.04 [95% CI, -0.07, -0.01]; p = .023) than those with the lowest scores. We conclude that high levels of schizotypy characteristics measured in early adolescence may be associated with distinguished features of sleep architecture, namely with spindle morphology and a higher proportion of REM sleep.

Narcolepsy type 1 and hypersomnia associated with a psychiatric disorder show different slow wave activity dynamics

The aim of the study was to compare electrophysiological parameters of night sleep in narcolepsy type 1 and hypersomnia associated with a psychiatric disorder. Fortyfour patients: 15 with narcolepsy type 1, 14 with hypersomnia associated with a psychiatric disorder and 15 age- and sex-matched controls participated in the study. The study subjects filled in the Athens Insomnia Scale (AIS) and the Beck Depression Inventory (BDI). The severity of daytime sleepiness was quantified subjectively using the Epworth Sleepiness Scale (ESS) and the Stanford Sleepiness Scale (SSS), and objectively using the Multiple Sleep Latency Test (MSLT). All subjects underwent polysomnography (PSG) on the two consecutive nights. The data from the second night was analysed. The slow wave activity (SWA, 1-4 Hz) was calculated for the three consecutive sleep cycles, and topographic delta power maps were plotted. In contrast to narcoleptics, psychiatric hypersomniacs had undisturbed nocturnal sleep, high sleep efficiency, normal non-rapid eye movement (NREM) and rapid eye movement (REM) sleep proportions, normal REM latency and sleep latencies on MSLT and PSG. The subjective and objective sleepiness was significantly higher in narcolepsy group than in psychiatric hypersomnia group. In all the study groups SWA was the most prominent in frontal areas, while the greatest between-group differences were found in the central areas. There were significant differences between the groups in SWA in the second NREM episode. The highest SWA was observed in the hypersomnia group, while the lowest in the narcolepsy group. Psychiatric hypersomniacs and controls did not differ in the SWA exponential decline over consecutive NREM episodes, whereas narcoleptics exhibited a steeper dissipation of sleep pressure from the first to the second NREM episode. In conclusion, narcolepsy type1 and hypersomnia associated with psychiatric disorder differ in the SWA dynamics. Narcoleptics presented with the altered dynamics of sleep homeostasis, whereas psychiatric hypersomniacs showed normal nocturnal sleep and normal sleep homeostasis.

Sleep behavior and depression: Findings from the China Kadoorie Biobank of 0.5 million Chinese adults

BACKGROUND

Mixed results have shown the association between sleep behavior and depression, but evidence relating the joint effect of sleep duration and sleep disturbances is limited, especially in Chinese population.

METHODS

A total of 512,891 adults aged 30-79 years from China Kadoorie Biobank (CKB) were included. Depression was defined by Composite International Diagnostic Inventory-short form (CIDI-SF). Sleep duration and sleep disturbances, including difficulty initiating and maintaining sleep (DIMS), early morning awakening (EMA), daytime dysfunction (DDF) and any sleep disturbances (ASD), were obtained by a self-reported questionnaire. Logistic regression was applied to examine the association between sleep behavior and depression.

RESULTS

About 23.1% of participants reported short sleep duration (≤ 6h), and 5.1% reported long sleep duration (> 9h). Compared with normal sleep duration (7-9h), both groups were associated greater likelihood of having depression (short sleep: OR = 2.32, 95%CI: 2.14-2.51; long sleep: OR = 1.56, 96%CI: 1.34-1.81). Participants reported sleep disturbances were significantly associated with depression (odds ratios ranged from 3.31 to 4.17). Moreover, the associations tended to be stronger for those who reported both abnormal sleep duration and sleep disturbances (p for interactions < 0.05), especially for those who slept long.

LIMITATIONS

The cross-sectional nature of the study design limits the interpretation of the results.

CONCLUSIONS

Abnormal sleep duration and sleep disturbances were associated with depression. The associations were stronger for abnormal sleep duration accompanied with sleep disturbances, especially for a long duration. More attention should be paid on these persons in clinical practice.

Is there any relationship between quality of life and polysomnographically detected sleep parameters/disorders in stable myasthenia gravis?

It is known that quality of life in myasthenia gravis is positively correlated with subjective sleep quality, still no data is available regarding the relationship between QOL and polysomnographically detected sleep parameters and disorders. In this study, we tried to highlighten this relationship, by performing polysomnography. Sleep-related complaints were evaluated in face-to-face interviews with 19 clinically stable MG patients and 26 healthy controls. During the interviews questionnaires assessing sleep quality, excessive daytime sleepiness, fatigue, depression, anxiety, and Turkish version of the MG-QOL 15-item scale [(MG-QOL15(T)] were administered and then an overnight polysomnography was performed. Sleep disorders, especially obstructive sleep apnea and fatigue were higher, whereas subjective sleep duration was significantly lower, in patients than controls. Excessive daytime sleepiness and poor sleep quality were not different between patients and controls. Other than percentage of sleep stage III, which was negatively correlated with MG-QOL15(T) scores, neither other sleep parameters nor sleep disorders were correlated with MG-QOL15(T) scores. MG composite, subjective sleep duration, fatigue severity and Hamilton depression rating scale scores were found to be positively correlated with MG-QOL15(T) scores. It was shown that decreasing disease severity and enhancing psychological well-being will improve patients' quality of life. We recommend that our findings should be repeated in a large prospective cohort of MG patients.

Disturbances of diurnal phase markers, behavior, and clock genes in a rat model of depression; modulatory effects of agomelatine treatment

Major depressive disorder (MDD) is a growing problem worldwide. Though, the etiology remains unresolved, circadian rhythm disturbances are frequently observed in MDD and thus is speculated to play a key role herein. The present study focuses on circadian rhythm disturbances in the chronic mild stress (CMS) animal model of depression and examined whether the atypical antidepressant, agomelatine, which is mediating its action via melatonergic and serotonergic receptors, is capable of resynchronizing the perturbed rhythm. Melatonin is often used as a marker of the circadian phase, but the functional and behavioral output is dictated on a cellular level by the molecular clock, driven by the clock genes. We applied in situ hybridization histochemistry to measure the expression levels of the core clock genes, period (Per) 1 and 2 and bone and muscle ARNT-like protein 1 (Bmal1), in multiple brain regions believed to be implicated in depression. Agomelatine showed an antidepressant-like effect in the sucrose consumption test and an anxiolytic-like profile in the elevated zero maze. We found that CMS increased nighttime melatonin release in rats and that agomelatine attenuated this effect. Stress was shown to have a time and region-specific effect on clock gene expression in the brain. Treatment with agomelatine failed to normalize clock gene expression, and the observed modifying effect on gene expression did not associate with the antidepressant-like effect. This suggests that the antidepressant actions of agomelatine are mainly independent of circadian rhythm synchronization and, in this regard, not superior to traditional antidepressants tested in our model.

Correlates of sleep disturbances in depressed older persons: the Netherlands study of depression in older persons (NESDO)

OBJECTIVES

Sleep disturbances are common among depressed older persons. To gain insight into sleep disturbances in late-life depression, their occurrence and correlates were assessed.

METHODS

Baseline data of 294 depressed older persons of the Netherlands Study of Depression in Older persons study were used. A diagnosis of current depression according to the diagnostic and statistical manual of mental disorders-IV (DSM-IV) was assessed with the Composite International Diagnostic Interview. Sleep disturbances were measured with the five-item Women's Health Initiative Insomnia Rating Scale, and considered present with a score of ≥10 points.

RESULTS

Sleep disturbances were present in 59.9% of the depressed older persons. Bivariate linear regression analyses showed that presence of sleep disturbances was associated with fewer years of education, use of alcohol, the number of chronic diseases, higher pain intensity scores, use of more benzodiazepines, more anxiety and severity of depressive symptoms. In multivariate analyses, severity of depression appeared to be the only independent correlate.

CONCLUSIONS

Sleep disturbances are highly prevalent in patients with late-life depression and independently correlated with the severity of depression. Treatment of depression may result in improvement of sleep disturbances, although cognitive behavioral interventions that focus on both depression and sleep disturbances may also be effective.

Obesity, Hypersomnolence, and Quality of Sleep: the Impact of Bariatric Surgery

PURPOSE

Obesity is commonly associated with poor sleep, excessive daytime sleepiness (EDS) and depressive mood but the impact of bariatric surgery on these conditions is incompletely understood. This study aimed to investigate the course of EDS and sleep quality in bariatric surgery patients in relation with changes in body weight and depressive symptoms.

METHODS

In patients consecutively submitted to bariatric surgery, baseline and postoperative sleep quality were evaluated by the Pittsburgh Sleep Quality Index (PSQI), excessive daytime sleepiness by the Epworth Sleepiness Scale (ESS), risk for OSA by the Berlin Questionnaire (BQ), and depressive symptoms by the Beck Depression Inventory-Short Form (BDI). Comorbidities were assessed by interview and chart review.

RESULTS

Sixty patients (M/F = 9/51) with a mean (±SD) age of 34.7 ± 9.2 years and body mass index (BMI) of 46.04 ± 7.52 kg/m² were studied. Bariatric surgery improved PSQI score (6.4 ± 3.8 versus 4.1 ± 2.8; p < 0.001), ESS score (8.1 ± 4.7 versus 6.0 ± 3.3; p < 0.001), BDI score (9.8 ± 7.0 versus 4.7 ± 4.6; p = 0.001), and risk for OSA (68.3 versus 5%). Twelve of the 18 subjects with baseline EDS (ESS ≥ 10) developed normal ESS score after surgery. In these subjects, significant postoperative improvement in depressive symptoms score was observed (12.0 ± 9.0 versus 5.5 ± 5.0; p = 0.041), in contrast to the remaining six cases with persistent EDS, who showed no significant change in these symptoms (5.5 ± 5.0 versus 3.2 ± 3.1; p = 0.416).

CONCLUSION

Bariatric surgery has a beneficial effect on sleep quality and EDS. Postoperative improvement in EDS can be related to a reduction in depressive symptoms.

Cardiac Vagal Control and Depressive Symptoms: The Moderating Role of Sleep Quality

Lower cardiac vagal control (CVC) has been linked to greater depression. However, this link has not been consistently demonstrated, suggesting the presence of key moderators. Sleep plausibly is one such factor. Therefore, we investigated whether sleep quality moderates the link between CVC (quantified by high-frequency heart rate variability, HF-HRV) and depressive symptoms (assessed using established questionnaires) in 29 healthy women. Results revealed a significant interaction between HF-HRV and sleep quality in predicting depressive symptoms: participants with lower HF-HRV reported elevated depressive symptoms only when sleep quality was also low. In contrast, HF-HRV was not associated with depressive symptoms when sleep quality was high, suggesting a protective function of high sleep quality in the context of lower CVC.

Modulation of Adult Hippocampal Neurogenesis by Sleep: Impact on Mental Health

The process of neurogenesis has been demonstrated to occur throughout life in the subgranular zone (SGZ) of the hippocampal dentate gyrus of several mammals, including humans. The basal rate of adult hippocampal neurogenesis can be altered by lifestyle and environmental factors. In this perspective review, the evidence for sleep as a modulator of adult hippocampal neurogenesis is first summarized. Following this, the impacts of sleep and sleep disturbances on hippocampal-dependent functions, including learning and memory, and depression are critically evaluated. Finally, we postulate that the effects of sleep on hippocampal-dependent functions may possibly be mediated by a change in adult hippocampal neurogenesis. This could provide a route to new treatments for cognitive impairments and psychiatric disorders.

The Cortisol Awakening Response and Depressive Symptomatology: The Moderating Role of Sleep and Gender

The association between depression and the cortisol awakening response (CAR) has been widely examined, yet the results are mixed and factors responsible for such inconsistencies are poorly understood. The current study investigated whether the link between depressive symptomatology and CAR varied as a function of two such factors: sleep and gender. The sample included 58 young adults (30 females; M_age  = 18.7; SD_age  = 0.91). Participants completed the Beck Depression Inventory as well as the Consensus Sleep Diary to assess depressive symptomatology and daily sleep patterns, respectively. Participants also provided four salivary cortisol samples (0, 30, 45 and 60 min after awakening) during two consecutive weekdays. Results demonstrated that greater depressive symptoms were associated with a greater CAR but only when depressive symptoms were linked to a shorter sleep time. In addition, gender significantly moderated the association between depressive symptoms and CAR. While greater depressive symptoms were associated with an elevated CAR among females, they were associated with a blunted CAR among males. These findings provide some insight into potential mechanisms linking depressive symptomatology and CAR, and suggest that future studies examining CAR as a biomarker of depression should account for differences in sleep and gender. Copyright © 2016 John Wiley & Sons, Ltd.

ipRGCs: possible causation accounts for the higher prevalence of sleep disorders in glaucoma patients

Sleep accounts for a third of one's lifetime, partial or complete deprivation of sleep could elicit sever disorders of body function. Previous studies have reported the higher prevalence of sleep disorders in glaucoma patients, but the definite mechanism for this phenomenon is unknown. On the other hand, it is well known by us that the intrinsically photosensitive retinal ganglion cells (ipRGCs) serve additional ocular functions, called non-image-forming (NIF) functions, in the regulation of circadian rhythm, melatonin secretion, sleep, mood and others. Specifically, ipRGCs can directly or indirectly innervate the central areas such as suprachiasmatic nucleus (SCN), downstream pineal gland (the origin of melatonin), sleep and wake-inducing centers and mood regulation areas, making NIF functions of ipRGCs relate to sleep. The more interesting thing is that previous research showed glaucoma not only affected visual functions such as the degeneration of classical retinal ganglion cells (RGCs), but also affected ipRGCs. Therefore, we hypothesize that higher prevalence of sleep disorders in glaucoma patients maybe result from the underlying glaucomatous injuries of ipRGCs leading to the abnormalities of diverse NIF functions corresponding to sleep.

Subjective sleep disturbance in Chinese adults with epilepsy: Associations with affective symptoms

BACKGROUND

As well as being a very common neurological disease worldwide, epilepsy significantly impairs patients' emotional, behavioral, and cognitive functioning. Sleep disturbances are the most frequent complaint in patients with epilepsy. The present study assesses the impact of a range of affective symptoms on subjective sleep quality and sleep disturbances in Chinese adults with epilepsy.

METHODS

Adults with epilepsy who visited our epilepsy clinic from July 2015 to March 2016 were enrolled in our study. Both patients and healthy controls completed the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Insomnia Severity Index (ISI), Beck Depression Inventory-II (BDI-II), Beck Anxiety Inventory (BAI), and Mini-mental State Examination (MMSE). Subjective sleep quality and sleep disturbances were examined with regard to self-reported symptoms of depression and anxiety, seizure-related factors, and demographic factors.

RESULTS

The PSQI scores and ISI scores of patients were significantly higher (indicating lower quality sleep and more serious insomnia) than those of the control group. Symptoms associated with depression and anxiety were independently related to impaired subjective sleep quality and insomnia. Affective symptoms explained more of the variance in PSQI scores and ISI scores than did seizure-related or demographic variables. In addition, these variables also seemed to be less powerful contributing factors to subjective sleep quality and insomnia than affective symptoms, several seizure-related factors, such as seizure control, partial seizures and duration of epilepsy, which are also significantly associated with subjective sleep quality and insomnia. In addition, use of lamotrigine (LTG) was also associated with insomnia and use of clonazepam (CZP) and phenobarbital (PB) with daytime sleepiness in patients with epilepsy.

CONCLUSION

Chinese adults with epilepsy have poorer self-reported subjective sleep quality and a higher prevalence of insomnia than the control group. Depressive- and anxiety-related symptoms independently exert an adverse effect on the subjective sleep quality and insomnia of patients. In addition, seizure control, partial seizures, and the duration of epilepsy affect the quality of sleep and insomnia in patients, but seem less powerful predictors of sleep quality and insomnia than affective symptoms. Early identification and treatment of affective symptoms is of great importance in improving the sleep quality and insomnia of patients with epilepsy.

Serum brain-derived neurotrophic factor (BDNF) in sleep-disordered patients: relation to sleep stage N3 and rapid eye movement (REM) sleep across diagnostic entities

Experimental and clinical evidence suggests an association between neuroplasticity, brain-derived neurotrophic factor and sleep. We aimed at testing the hypotheses that brain-derived neurotrophic factor is associated with specific aspects of sleep architecture or sleep stages in patients with sleep disorders. We included 35 patients with primary insomnia, 31 patients with restless legs syndrome, 17 patients with idiopathic hypersomnia, 10 patients with narcolepsy and 37 healthy controls. Morning serum brain-derived neurotrophic factor concentrations were measured in patients and controls. In patients, blood sampling was followed by polysomnographic sleep investigation. Low brain-derived neurotrophic factor levels were associated with a low percentage of sleep stage N3 and rapid eye movement sleep across diagnostic entities. However, there was no difference in brain-derived neurotrophic factor levels between diagnostic groups. Our data indicate that serum levels of brain-derived neurotrophic factor, independent of a specific sleep disorder, are related to the proportion of sleep stage N3 and REM sleep. This preliminary observation is in accordance with the assumption that sleep stage N3 is involved in the regulation of neuroplasticity.

Life-time history of insomnia and hypersomnia symptoms as correlates of alcohol, cocaine and heroin use and relapse among adults seeking substance use treatment in the United States from 1991 to 1994

AIMS

To examine the association between a life-time history of insomnia and hypersomnia compared with no sleep disturbance and substance use patterns and amounts before and after a substance use treatment episode.

DESIGN

Secondary analysis of data from the Drug Abuse Treatment Outcome Studies conducted from 1991 to 1994.

SETTING

Data were collected at 96 substance use treatment programs in 11 United States cities, including short-term in-patient, long-term residential, methadone maintenance and out-patient drug-free treatment modalities.

PARTICIPANTS

Study samples included 7168 adults at treatment entry and 2965 at 12 months post-treatment entry whose primary substance use at entry was alcohol (14.7%), cocaine (62.7%) or heroin (22.6%).

MEASUREMENTS

Life-time history of insomnia and hypersomnia was assessed via self-report. Type and frequency of substance use were assessed at treatment entry. Substance use was also assessed 12 months following treatment completion. Associations were examined using linear and logistic regression with age, sex, race, education level, depression history, treatment modality and in-treatment substance use as covariates.

FINDINGS

Life-time history of insomnia, hypersomnia, both or neither was reported by 26.3, 9.5, 28.0 and 36.2% of participants, respectively. Compared with no sleep disturbance, life-time insomnia and hypersomnia were associated at treatment entry with unique substance use patterns and a higher frequency of any substance use (P < 0.001). All types of sleep disturbance were associated with higher rates of cocaine use at 12-month post-entry (odds ratios: 1.30-1.57).

CONCLUSIONS

There is evidence of an adverse association between substance use and sleep disturbance including higher frequency of all substance use before substance abuse treatment and higher rates of cocaine use after a treatment episode.

Sleep Duration and Sleep Quality: Associations With Depressive Symptoms Across Adolescence

This study explored whether short sleep duration and sleep quality mediate the relationship between age and depressive symptoms. For comparison, we also explored whether depressive symptoms mediate the relationship between age and short sleep duration and sleep quality. The sample comprised 741 adolescents (63.5% female, mean age 15.78 years, range 11.92-19.67 years) in grades 7-12 from 11 secondary schools in metropolitan Melbourne, Australia. Students completed the Pittsburgh Sleep Quality Index (PSQI) and Center for Epidemiologic Studies Depression Scale (CES-D). Path analyses suggested that short sleep duration significantly mediated the relationship between age and depressive symptoms. Poor sleep quality also significantly mediated this relationship when sleep quality was defined by subjective judgement, but not sleep disturbance, sleep efficiency, or sleep onset latency. Depressive symptoms significantly mediated the relationship between age and short sleep duration and sleep quality (subjective judgement, sleep disturbance, sleep efficiency, and sleep onset latency). These findings suggest that the population-wide increase in depressive symptoms across adolescence is partially mediated by sleep-related developmental changes. They also highlight the importance of examining specific sleep problems when investigating the relationship between sleep and mood in this age group.

Depressive Symptoms Are Associated With Objectively Measured Sleep Parameters in Kidney Transplant Recipients

STUDY OBJECTIVES

Both depression and sleep complaints are very prevalent among kidney transplant (kTx) recipients. However, details of the complex relationship between sleep and depression in this population are not well documented. Thus, we investigated the association between depressive symptoms and sleep macrostructure parameters among prevalent kTx recipients.

METHODS

Ninety-five kTx recipients participated in the study (54 males, mean ± standard devation age 51 ± 13 years, body mass index 26 ± 4 kg/m2, estimated glomerular filtration rate 53 ± 19 ml/min/1.73 m2). Symptoms of depression were assessed by the Center for Epidemiologic Studies - Depression Scale (CES-D). After 1-night polysomnography each recording was visually scored and sleep macrostructure was analyzed.

RESULTS

The CES-D score was significantly associated with the amount of stage 2 sleep (r = 0.20, P < .05), rapid eye movement (REM) latency (r = 0.21, P < .05) and REM percentage (r = -0.24, P < .05), but not with the amount of slow wave sleep (r = -0.12, P > .05). In multivariable linear regression models the CES-D score was independently associated with the amount of stage 2 sleep (β: 0.205; confidence interval: 0.001-0.409; P = .05) and REM latency (β: 0.234; confidence interval: 0.001-0.468; P = .05) after adjustment for potential confounders.

CONCLUSIONS

Depressive symptoms among kTx recipients are associated with increased amount of stage 2 sleep and prolonged REM latency. Further studies are needed to confirm our findings and understand potential clinical implications.

Bidirectionality Between Sleep Symptoms and Core Depressive Symptoms and Their Long-Term Course in Major Depression

OBJECTIVE

To investigate the bidirectional dynamic relationship between sleep symptoms and core depressive symptoms and to identify subgroups differing with respect to their course.

METHODS

The weekly state of depressive symptoms in depressed primary care patients (N = 267) was assessed retrospectively every 3 months for 3 consecutive years. The bidirectional relationship between sleep and core symptoms was estimated by means of manifest Markov modeling. Data-driven subgroups were estimated with parallel processes-latent class growth analyses to identify differences in courses of sleep and core symptoms.

RESULTS

In total, core symptoms were associated with next-week development (odds = 1.42; 95% confidence interval [CI] = 1.20-1.67; p < .001) and remission of sleep symptoms (odds = 0.86; 95% CI 0.75 to 0.99, p = .033).Evidence was also found for a reverse pathway such that sleep symptoms were associated with the development (odds = 1.26; 95% CI = 1.05-1.50; p = .012) and remission of core symptoms (odds = 0.87; 95% CI = 0.76-0.99; p = .038). Three classes with different 3-year courses were derived. In class 1, the likelihood that core symptoms remitted was reduced if sleep symptoms were present, and symptoms remained present over 3 years. In class 2, symptoms were bidirectionally related and remitted over 3 years. In class 3, symptoms were not associated, and sleep symptoms declined less steeply than core depressive symptoms.

CONCLUSIONS

The results suggest that sleep symptoms should be treated alongside core depressive symptoms in patients with an asynchronic decrease of sleep and core symptoms and in patients that do not respond to treatment to increase the chance of complete remission.

Neurophysiological correlates of suicidal ideation in major depressive disorder: Hyperarousal during sleep

BACKGROUND

Suicide is a major public health concern, and a barrier to reducing the suicide rate is the lack of objective predictors of risk. The present study considers whether quantitative sleep electroencephalography (EEG) may be a neurobiological correlate of suicidal ideation.

METHODS

Participants included 84 (45 female, mean age=26.6) adults diagnosed with major depressive disorder (MDD). The item that measures thoughts of death or suicide on the Quick Inventory of Depressive Symptomatology (QIDS) was used to classify 47 participants as low suicidal ideation (24 females, mean age=26.1) and 37 as high suicidal ideation (21 females, mean age=27.3). Data were obtained from archival samples collected at the University of Michigan and University of Texas Southwestern Medical Center between 2004 and 2012. Sleep EEG was quantified using power spectral analysis, and focused on alpha, beta, and delta frequencies.

RESULTS

Results indicated that participants with high compared to low suicidal ideation experienced 1) increased fast frequency activity, 2) decreased delta activity, and 3) increased alpha-delta sleep after adjusting for age, sex, depression, and insomnia symptoms.

LIMITATIONS

Limitations include the exclusion of imminent suicidal intent, a single suicidal ideation item, and cross-sectional archival data.

CONCLUSIONS

This is one of the first studies to provide preliminary support that electrophysiological brain activity during sleep is associated with increased suicidal ideation in MDD, and may point toward central nervous system (CNS) hyperarousal during sleep as a neurobiological correlate of suicidal ideation.

Meet Spinky: An Open-Source Spindle and K-Complex Detection Toolbox Validated on the Open-Access Montreal Archive of Sleep Studies (MASS)

Sleep spindles and K-complexes are among the most prominent micro-events observed in electroencephalographic (EEG) recordings during sleep. These EEG microstructures are thought to be hallmarks of sleep-related cognitive processes. Although tedious and time-consuming, their identification and quantification is important for sleep studies in both healthy subjects and patients with sleep disorders. Therefore, procedures for automatic detection of spindles and K-complexes could provide valuable assistance to researchers and clinicians in the field. Recently, we proposed a framework for joint spindle and K-complex detection (Lajnef et al., 2015a) based on a Tunable Q-factor Wavelet Transform (TQWT; Selesnick, 2011a) and morphological component analysis (MCA). Using a wide range of performance metrics, the present article provides critical validation and benchmarking of the proposed approach by applying it to open-access EEG data from the Montreal Archive of Sleep Studies (MASS; O'Reilly et al., 2014). Importantly, the obtained scores were compared to alternative methods that were previously tested on the same database. With respect to spindle detection, our method achieved higher performance than most of the alternative methods. This was corroborated with statistic tests that took into account both sensitivity and precision (i.e., Matthew's coefficient of correlation (MCC), F1, Cohen κ). Our proposed method has been made available to the community via an open-source tool named Spinky (for spindle and K-complex detection). Thanks to a GUI implementation and access to Matlab and Python resources, Spinky is expected to contribute to an open-science approach that will enhance replicability and reliable comparisons of classifier performances for the detection of sleep EEG microstructure in both healthy and patient populations.

The 'affect tagging and consolidation' (ATaC) model of depression vulnerability

Since the 1960's polysomnographic sleep research has demonstrated that depressive episodes are associated with REM sleep alterations. Some of these alterations, such as increased REM sleep density, have also been observed in first-degree relatives of patients and remitted patients, suggesting that they may be vulnerability markers of major depressive disorder (MDD), rather than mere epiphenomena of the disorder. Neuroimaging studies have revealed that depression is also associated with heightened amygdala reactivity to negative emotional stimuli, which may also be a vulnerability marker for MDD. Several models have been developed to explain the respective roles of REM sleep alterations and negatively-biased amygdala activity in the pathology of MDD, however the possible interaction between these two potential risk-factors remains uncharted. This paper reviews the roles of the amygdala and REM sleep in the encoding and consolidation of negative emotional memories, respectively. We present our 'affect tagging and consolidation' (ATaC) model, which argues that increased REM sleep density and negatively-biased amygdala activity are two separate, genetically influenced risk-factors for depression which interact to promote the development of negative memory bias - a well-known cognitive vulnerability marker for depression. Predictions of the ATaC model may motivate research aimed at improving our understanding of sleep dependent memory consolidation in depression aetiology.