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

Association between sleep duration, suicidal ideation, and suicidal attempts among Chinese adolescents: The moderating role of depressive symptoms

BACKGROUND

Suicidal ideation and attempts are still currently serious problems among adolescents worldwide, and there is evidence that sleep problem may be associated with increased rates of mental disorder. This study aimed to examine the associations between sleep duration and suicidal ideation and attempts among adolescents and to test whether depressive symptoms have moderating effects on the associations.

METHODS

A 3-stage, stratified cluster, random sampling method was used to collect data from 20,130 high school students in southeast China.

RESULTS

The weighted prevalence of short sleep among Chinese adolescents was 5.6% (95% CI, 5.3-6.0%), and the weighted prevalence of long sleep was 2.7% (95% CI, 2.5-3.0%). The final results demonstrated that short sleep was positively associated with suicidal ideation (AOR=2.28, 95% CI=1.96-2.66) and suicidal attempts (AOR=3.20, 95% CI=2.46-4.16), and long sleep was only significantly associated with suicidal attempts (AOR=2.47, 95% CI=1.70-3.58). Stratification analyses conducted separately for students with and without depressive symptoms demonstrated that depressive symptoms may have moderating effects on the associations between sleep duration and suicidality.

LIMITATIONS

Our study sample only included school students, and causal inference could not be examined due to the cross-sectional design.

CONCLUSIONS

Sleep duration was associated with suicidal ideation and attempts, and the association between sleep duration and suicidal attempts was U-shaped. These findings support that proper treatments services with the potential to restore adolescent normal sleep would be helpful in preventing suicidality among adolescents.

Circadian Forced Desynchrony of the Master Clock Leads to Phenotypic Manifestation of Depression in Rats

In mammals, a master circadian clock within the suprachiasmatic nucleus (SCN) of the hypothalamus maintains the phase coherence among a wide array of behavioral and physiological circadian rhythms. Affective disorders are typically associated with disruption of this fine-tuned “internal synchronization,” but whether this internal misalignment is part of the physiopathology of mood disorders is not clear. To date, depressive-like behavior in animal models has been induced by methods that fail to specifically target the SCN regulation of internal synchronization as the mode to generate depression. In the rat, exposure to a 22-h light-dark cycle (LD22) leads to the uncoupling of two distinct populations of neuronal oscillators within the SCN. This genetically, neurally, and pharmacologically intact animal model represents a unique opportunity to assess the effect of a systematic challenge to the central circadian pacemaker on phenotypic manifestations of mood disorders. We show that LD22 circadian forced desynchrony in rats induces depressive-like phenotypes including anhedonia, sexual dysfunction, and increased immobility in the forced swim test (FST), as well as changes in the levels and turnover rates of monoamines within the prefrontal cortex. Desynchronized rats show increased FST immobility during the dark (active) phase but decreased immobility during the light (rest) phase, suggesting a decrease in the amplitude of the normal daily oscillation in this behavioral manifestation of depression. Our results support the notion that the prolonged internal misalignment of circadian rhythms induced by environmental challenge to the central circadian pacemaker may constitute part of the etiology of depression.

Factors Influencing Clinical Correlates of Chronic Traumatic Encephalopathy (CTE): a Review

Chronic traumatic encephalopathy (CTE) is a neuropathologically defined disease reportedly linked to a history of repetitive brain trauma. As such, retired collision sport athletes are likely at heightened risk for developing CTE. Researchers have described distinct pathological features of CTE as well a wide range of clinical symptom presentations, recently termed traumatic encephalopathy syndrome (TES). These clinical symptoms are highly variable, non-specific to individuals described as having CTE pathology in case reports, and are often associated with many other factors. This review describes the cognitive, emotional, and behavioral changes associated with 1) developmental and demographic factors, 2) neurodevelopmental disorders, 3) normal aging, 4) adjusting to retirement, 5) drug and alcohol abuse, 6) surgeries and anesthesia, and 7) sleep difficulties, as well as the relationship between these factors and risk for developing dementia-related neurodegenerative disease. We discuss why some professional athletes may be particularly susceptible to many of these effects and the importance of choosing appropriate controls groups when designing research protocols. We conclude that these factors should be considered as modifiers predominantly of the clinical outcomes associated with repetitive brain trauma within a broader biopsychosocial framework when interpreting and attributing symptom development, though also note potential effects on neuropathological outcomes. Importantly, this could have significant treatment implications for improving quality of life.

The relationship between micronutrient status and sleep patterns: a systematic review

OBJECTIVE

To review articles on the relationship of dietary and circulating micronutrients with sleep patterns, and to identify issues surrounding implications for future research and public health practice.

DESIGN

A systematic review was conducted. PubMed, Embase and Scopus were searched through January 2016.

SETTING

Both experimental and observational studies were included. However, studies that focused on secondary sleep impairment due to comorbidities were excluded.

SUBJECTS

Individuals in different age groups, from infants to older adults.

RESULTS

A total of twenty-six articles were selected. In the articles reviewed, researchers generally supported a potential role of micronutrients, particularly Fe and Mg, in the development of sleep stages among infants and in reversing age-related alterations in sleep architecture in older adults. Micronutrient status has also been linked to sleep duration, with sleep duration positively associated with Fe, Zn and Mg levels, and negatively associated with Cu, K and vitamin B12 levels. The mechanisms underlying these relationships include the impact of micronutrients on excitatory/inhibitory neurotransmitters and the expression of circadian genes.

CONCLUSIONS

Although the number of studies on the relationship between micronutrient status and sleep remains low, evidence has emerged that suggests a link between dietary/circulating micronutrients and sleep. Future research is needed to investigate the dose-dependent as well as the longitudinal relationships between micronutrient levels and human sleep across populations, test the interactions among micronutrients on sleep outcomes, and ultimately examine the clinical relevance of micronutrients on sleep health.

Depression, anxiety, and tobacco use: Overlapping impediments to sleep in a national sample of college students

OBJECTIVES

To examine how tobacco use and depression/anxiety disorders are related to disturbed sleep in college students.

PARTICIPANTS

85,138 undergraduate respondents (66.3% female, 74.5% white, non-Hispanic, ages 18-25) from the Spring 2011 American College Health Association-National College Health Assessment II database.

METHODS

Multivariate analyses of tobacco use (none, intermediate, daily) and mental health (diagnosed and/or symptomatic depression or anxiety) were used to predict sleep disturbance.

RESULTS

Daily tobacco use was associated with more sleep problems than binge drinking, illegal drug use, obesity, gender, and working >20 hours/week. Students with depression or anxiety reported more sleep disturbances than individuals without either disorder, and tobacco use in this population was associated with the most sleep problems.

CONCLUSIONS

Tobacco use and depression/anxiety disorders are both independently associated with more sleep problems in college students. Students with depression and/or anxiety are more likely to be daily tobacco users, which likely exacerbates their sleep problems.

Sleep Architecture Relates to Daytime Affect and Somatic Complaints in Clinically Anxious but Not Healthy Children

It is increasingly clear that seminal sleep-affective relationships begin to take root in childhood, yet studies exploring how nighttime sleep characteristics relate to daytime affective symptoms, both in clinical and healthy populations of children, are lacking. The current study sought to explore these relationships by investigating whether trait-like and/or daily reports of affective and somatic symptoms of children with generalized anxiety disorder and matched controls relate to sleep architecture. Sixty-six children (ages 7-11; 54.4% female; 56.1% Caucasian; 18.2% biracial; 6.1% African American; 3% Asian; 16.7% Hispanic) participated including 29 with primary generalized anxiety disorder (without comorbid depression) and 37 healthy controls matched on age and race/ethnicity. Participants underwent structured diagnostic assessments including child-report measures and subsequently reported on their negative affect and somatic symptoms over the course of 1 week. Children also completed 1 night of polysomnography. Among children with generalized anxiety disorder only, greater amounts of slow wave sleep corresponded with less negative affect, and greater amounts of rapid eye movement sleep was related to more somatic complaints across the week. Similarly, for trait-like measures, more rapid eye movement sleep and shorter latency to rapid eye movement sleep were related to greater depressive symptoms in the anxious group only. The current findings suggest that physiologic sleep characteristics may contribute in direct ways to the symptom profiles of clinically anxious children. The functional relevance of such findings (e.g., how specific sleep characteristics serve to either increase or reduce long-term risk) is a vital direction for future research.

Relationships of Sleep Duration With Weight-Related Behaviors of U.S. College Students

This study describes sleep behaviors of U.S. college students (N = 1,252; 18-24 years old; 59% female) and examines associations of sleep duration with weight-related behaviors. More than one quarter of participants slept < 7 hr/night and had mean Pittsburgh Sleep Quality Index (PSQI) scores indicating poor sleep quality. There were significant differences for all PSQI scales among sleep duration categories, < 7 hr (n = 344), 7-8 hr (n = 449), ≥ 8 hr (n = 459) sleep/night. Compared to those who slept ≥ 8 hr, those who slept < 8 hr had significantly more negative eating attitudes (2% higher), poorer internal regulation of food (4% lower), and greater binge eating (4% higher) scores. Findings advocate for health care professionals to evaluate sleep behaviors of college students during office visits and promote good sleep behaviors.

Goodness of fit between prenatal maternal sleep and infant sleep: Associations with maternal depression and attachment security

The current study prospectively examined the ways in which goodness of fit between maternal and infant sleep contributes to maternal depressive symptoms and the mother-child relationship across the first years of life. In a sample of 173 mother-child dyads, maternal prenatal sleep, infant sleep, maternal depressive symptoms, and mother-child attachment security were assessed via self-report, actigraphy, and observational measures. Results suggested that a poor fit between mothers' prenatal sleep and infants' sleep at 8 months (measured by sleep diary and actigraphy) was associated with maternal depressive symptoms at 15 months. Additionally, maternal depression mediated the association between the interplay of mother and infant sleep (measured by sleep diary) and mother-child attachment security at 30 months. Findings emphasize the importance of the match between mother and infant sleep on maternal wellbeing and mother-child relationships and highlight the role of mothers' perceptions of infant sleep.

Sleep Disturbance and Depression as Barriers to Adherence

This study examined the relationships among subjective sleep disturbance, depressive symptoms, and adherence to medications among HIV-infected women. HIV-infected women ( N = 173) were recruited through community AIDS service organizations throughout South Carolina. Participants completed the Pittsburgh Sleep Quality Index (PSQI), the Centers for Epidemiological Studies Depression Scale (CES-D), and a modified version of the Adults AIDS Clinical Trials Group Adherence Baseline Questionnaire. Women who reported greater sleep disturbance also reported a higher level of depressive symptoms and reported poor adherence to their medication regimen. Depression helped to explain the relationship between sleep quality and adherence. Results indicate that assessment and management of sleep disturbance and depressive symptoms in women with HIV disease is important to promote medication adherence.

Postpartum depressive symptoms and its association to daytime sleepiness and restless legs during pregnancy

Background

Postpartum depression is a common condition, which consequences might be harmful for both mother and child. Since sleep and depression are closely related it is possible that women who suffer from sleep related problems during pregnancy are more likely to develop depression in the postpartum period. This study aims to investigate the possible association between depressive symptoms in the postpartum period and sleep related problems during pregnancy.

Methods

In this study 293 women in the last trimester of pregnancy answered a questionnaire about symptoms of restless legs, snoring and daytime sleepiness. They also completed the Epworth Sleepiness Scale (ESS). The same women were screened for depressive symptoms using the Edinburgh Postnatal Depression Scale (EPDS) four to ten weeks after giving birth. Additional information about social data, pregnancy and delivery was received from the medical charts.

Results

Women with postpartum depressive symptoms had higher prevalence of excessive daytime sleepiness defined as ESS score ≥10 (OR 3.84, CI 1.57–9.39), and restless legs syndrome (OR 2.837 CI 1.18–6.84) in last trimester of pregnancy, when adjusted for socio-demographic factors and obstetric risk factors. No association was found between postpartum depressive symptoms and snoring.

Conclusions

Depressive symptoms after childbirth are preceded by sleep related problems such as daytime sleepiness and restless legs, already during pregnancy. The results from Epworth Sleepiness Scale and a questionnaire concerning Restless Legs Syndrome completed during pregnancy might be a valuable contribution for detecting women at risk for postpartum depression, enabling preventive interventions.

Is there a bi-directional relationship between depression and obesity among adult men and women? Systematic review and bias-adjusted meta analysis

The rapidly increasing prevalence of both obesity and depression represent two major public health concerns worldwide. But the evidence regarding the direction and strength of the association between these two disorders, for both adult men and women, are remain inconclusive. We systematically reviewed publications from five different databases: Pubmed, Embase, BIOSIS, CINAHL and PsychINFO. A total of 21 articles were included for the systematic review and 19 of them for the meta-analysis using a bias-adjusted (quality effect) model. This resulted in the inclusion of approximately 226,063 (33.7% men) participants. Those who were depressed had a 37% (RR: 1.37, 95% CI: 1.17, 1.48) increased risk of being obese, and who were obese had an 18% increased risk of being depressed (RR: 1.18, 95% CI: 1.04, 1.35). Those who were depressed had a 2% (RD: 0.02, 95% CI: 0.01, 0.03) excess risk of obesity, however, the reciprocal associations were not significant. The association between overweight and depression was not found significant in either direction. Both men and women were at risk of obesity and depression bi-directionally. In sensitivity analyses bi-directional associations were more pronounced among young and middle aged adults and in studies with longer follow-up. The findings of this study suggest that the strength of the association is greater for the direction leading from depression to obesity and this link was more pronounced for young and middle aged women.

Brain Systems Underlying Susceptibility to Helplessness and Depression

There has been a relative lack of research into the neurobiological predispositions that confer vulnerability to depression. This article reviews functional brain mappings from a genetic animal model, the congenitally helpless rat, which is predisposed to develop learned helplessness. Neurometabolic findings from this model are integrated with the neuroscientific literature from other animal models of depression as well as depressed humans. Changes in four major brain systems are suggested to underlie susceptibility to helplessness and possibly depression: (a) an unbalanced prefrontal-cingulate cortical system, (b) a dissociated hypothalamic-pituitary-adrenal axis, (c) a dissociated septal-hippocampal system, and (d) a hypoactive brain reward system, as exemplified by a hypermetabolic habenula-interpeduncular nucleus pathway and a hypometabolic ventral tegmental area-striatum pathway. Functional interconnections and causal relationships among these systems are considered and further experiments are suggested, with theoretical attention to how an abnormality in any one system could affect the others.

Reciprocal dynamics between self-rated sleep and symptoms of depression and anxiety in young adult women: a 14-day diary study

OBJECTIVES

The objective of this study was to characterize the day-to-day associations among sleep disturbance, depression, and anxiety in a sample of young adult women.

METHODS

One hundred and seventy-one women (20.1 ± 3.3 years) completed in-laboratory baseline assessment followed by daily online surveys across a two-week period. Daily measures included the Mood and Anxiety Symptom Questionnaire-Short Form to assess shared and disorder-specific symptoms of depression and anxiety (general distress, anhedonic depression, and anxious arousal), as well as self-reported total sleep time (TST), sleep-onset latency (SOL), and sleep quality (SQ).

RESULTS

Findings supported bidirectional day-to-day relationships between sleep and affective symptoms. When women felt greater general distress (shared features of anxiety and depression), they experienced longer SOL and worse SQ at night. Specificity among depression, anxiety, and sleep disturbance was observed such that higher levels of depression-specific anhedonia presaged longer SOL, shorter TST, and poorer SQ. In the other direction, when women had poor-quality sleep, they later experienced greater anhedonic depression and anxious arousal. The influence of TST on anhedonia was complex such that a single night of short sleep led to less anhedonic depression the next day, whereas women who obtained shorter sleep across the two-week period reported greater anhedonia.

CONCLUSIONS

Reciprocal dynamics between nightly sleep disturbance and daily experiences of depression and anxiety may serve as a process by which insomnia, depression, and anxiety develop into comorbid clinical states over time in women. The associations of anhedonic depression with nightly sleep disturbance and chronic short sleep were especially toxic, offering insight into daily mechanisms driving the most prevalent phenotype of comorbid insomnia.

Automatic Sleep Stage Scoring Using Time-Frequency Analysis and Stacked Sparse Autoencoders

We developed a machine learning methodology for automatic sleep stage scoring. Our time-frequency analysis-based feature extraction is fine-tuned to capture sleep stage-specific signal features as described in the American Academy of Sleep Medicine manual that the human experts follow. We used ensemble learning with an ensemble of stacked sparse autoencoders for classifying the sleep stages. We used class-balanced random sampling across sleep stages for each model in the ensemble to avoid skewed performance in favor of the most represented sleep stages, and addressed the problem of misclassification errors due to class imbalance while significantly improving worst-stage classification. We used an openly available dataset from 20 healthy young adults for evaluation. We used a single channel of EEG from this dataset, which makes our method a suitable candidate for longitudinal monitoring using wearable EEG in real-world settings. Our method has both high overall accuracy (78%, range 75-80%), and high mean [Formula: see text]-score (84%, range 82-86%) and mean accuracy across individual sleep stages (86%, range 84-88%) over all subjects. The performance of our method appears to be uncorrelated with the sleep efficiency and percentage of transitional epochs in each recording.

Wheel running improves REM sleep and attenuates stress-induced flattening of diurnal rhythms in F344 rats

Regular physical activity produces resistance to the negative health consequences of stressor exposure. One way that exercise may confer stress resistance is by reducing the impact of stress on diurnal rhythms and sleep; disruptions of which contribute to stress-related disease including mood disorders. Given the link between diurnal rhythm disruptions and stress-related disorders and that exercise both promotes stress resistance and is a powerful non-photic biological entrainment cue, we tested if wheel running could reduce stress-induced disruptions of sleep/wake behavior and diurnal rhythms. Adult, male F344 rats with or without access to running wheels were instrumented for biotelemetric recording of diurnal rhythms of locomotor activity, heart rate, core body temperature (CBT), and sleep (i.e. REM, NREM, and WAKE) in the presence of a 12 h light/dark cycle. Following 6 weeks of sedentary or exercise conditions, rats were exposed to an acute stressor known to disrupt diurnal rhythms and produce behaviors associated with mood disorders. Prior to stressor exposure, exercise rats had higher CBT, more locomotor activity during the dark cycle, and greater %REM during the light cycle relative to sedentary rats. NREM and REM sleep were consolidated immediately following peak running to a greater extent in exercise, compared to sedentary rats. In response to stressor exposure, exercise rats expressed higher stress-induced hyperthermia than sedentary rats. Stressor exposure disrupted diurnal rhythms in sedentary rats; and wheel running reduced these effects. Improvements in sleep and reduced diurnal rhythm disruptions following stress could contribute to the health promoting and stress protective effects of exercise.

Social and behavioral predictors of insufficient sleep among African Americans and Caucasians

BACKGROUND

Few studies have examined the social and behavioral predictors of insufficient sleep.

OBJECTIVE

To assess the social and behavioral predictors of insufficient sleep in the U.S.

METHODS

Data from the 2009 Behavioral Risk Factor Surveillance System (BRFSS) were analyzed. Telephone interviews were conducted in six representative states that completed the optional sleep module. A total of 31,059 respondents were included in the present analysis. BRFSS-provided weights were applied to analyses to adjust for the use of complex design.

RESULTS

The mean age for the sample was 56 ± 16 years, with 63% of the sample being female; 88% identified as non-Hispanic white and 12% identified as non-Hispanic black; 42% were not married and 8% did not have a high school degree. The prevalence of insufficient sleep (<7 hours) was 37%. Multivariate-adjusted logistic regression revealed associations of four important factors with insufficient sleep, which were: working more than 40 hours per week [OR = 1.65, p < 0.001, 95% CI = 1.65-1.66], black race/ethnicity [OR = 1.37, p < 0.001, 95% CI = 1.37-1.38], history of heart disease [OR = 1.26, p < 0.001, 95% CI = 1.25-1.28], care-giving to family/friends [OR = 1.50, p < 0.001, 95% CI = 1.49-1.51], and lack of social and emotional support [OR = 1.24, p < 0.001, 95% CI = 1. 23-1.25].

CONCLUSION

Social and behavioral predictors of health uniquely contribute to the report of insufficient sleep and should be considered when developing programs to increase awareness of the adverse effects of insufficient sleep.

Polysomnographic characteristics of bipolar hypomanic patients: Comparison with unipolar depressed patients

BACKGROUND

Sleep profile in bipolar disorder has received little attention in comparison to sleep studies in major depressive disorders. Specific sleep abnormalities especially in REM sleep parameters have been detected in depression. The current study aimed at investigating whether bipolar disorder shares the same polysomnographic (PSG) changes or not.

METHODS

All night polysomnographic assessments were made for 20 patients diagnosed to have hypomania, in addition to 20 patients with major depression and 20 healthy matched controls. All participants were examined using Standardized Sleep Questionnaire, SCID-I for psychiatric diagnosis, based on DSM-IV criteria, YMRS (for hypomanic patients), HAMD (for major depression patients), and all-night polysomnography (for all subjects).

RESULTS

The two patient groups differed significantly from controls in their sleep profile, especially regarding sleep continuity measures, Short REML (Rapid Eye Movement Latency), with increased REMD (Rapid Eye Movement sleep density). High similarity was found in EEG sleep profile of the two patient groups, though the changes were more robust in patients with depression

LIMITATIONS

A relatively small sample size, the absence of follow up assessment, lack of consideration of other variables like body mass index, nicotine and caffeine intake.

CONCLUSION

Similarity in EEG sleep profile between Bipolar disorder patients and patients with major depression suggests a common biological origin for both conditions, with the difference being "quantitative" rather than "qualitative". This quantitative difference in sleep efficiency and SWS (Slow wave sleep), being higher in hypomania, might explain the rather "refreshing" nature of sleep in hypomanic patients, compared to depression.

Determinants of cortisol awakening responses to naps and nighttime sleep

The cortisol awakening response (CAR) is a phenomenon describing the sharp increase in basal cortisol levels shortly after waking from sleep. While extensively studied, little is known about the role of sleep architecture contributing to CAR. Furthermore, the potential for CAR after a shorter bout of sleep--a nap--has not been directly investigated. The current studies thus aimed at assessed sleep duration, time of day, and sleep architecture as potential determinants of the cortisol awakening response. Saliva samples were collected during the first hour (0, 30, 45, 60 min) following several EEG-monitored laboratory sleep conditions. Those included afternoon naps wherein 17 participants (4 men; ages 18-26) napped for 50 min and 24 participants (11 men; ages 18-24) napped for 90 min. Furthermore, 20 participants (10 men; ages 18-35) visited the lab twice and in addition to staying overnight, napped 90 min in the morning either under placebo conditions or pharmacologically-manipulated sleep conditions (5mg Zolpidem). Cortisol increases were observed in response to each sleep condition except to 50-min afternoon naps. Furthermore, CARs were predicted by Stage 2 sleep when following nighttime sleep (r=.46, p=.04) and by Stage 1 sleep when following placebo morning naps (r=.54, p=.01). The current study established cortisol awakening responses to naps and implicates sleep duration and architecture in the generation of CAR to both napping and nighttime sleep. Assessing CAR in conjunction with the specific type of sleep may thus contribute to our understanding of mechanisms underlying positive and negative health effects of napping.

A pilot study of serotonin-1A receptor genotypes and rapid eye movement sleep sensitivity to serotonergic/cholinergic imbalance in humans: a pharmacological model of depression

RATIONALE

The serotonergic and cholinergic systems are jointly involved in regulating sleep but this system is theorized to be disturbed in depressed individuals. We previously reported that cholinergic and serotonergic agents induce sleep changes partially consistent with monoamine models of sleep disturbances in depression. One potential cause of disturbed neurotransmission is genetic predisposition. The G(-1019) allele of the serotonin-1A (5-HT1A) receptor promoter region predicts an increased risk for depression compared to the wild-type C(-1019) allele.

OBJECTIVE

The goal of this study was to investigate how serotonin-1A receptor genotypes mediate sleep sensitivity to pharmacological probes modeling the serotonergic/cholinergic imbalance of depression.

METHODS

Seventeen healthy female participants homozygous for either C (n=11) or G (n=6) alleles aged 18-27 years were tested on four nonconsecutive nights. Participants were given galantamine (an anti-acetylcholinesterase), buspirone (a serotonergic agonist), both drugs together, or placebos before sleeping.

RESULTS

As reported previously, buspirone significantly increased rapid eye movement (REM) latency (P<0.001), as well as awakenings, percentage of time spent awake, and percentage of time asleep spent in stage N1 (P<0.019). Galantamine increased awakenings, percentage of time spent awake, percentage of time asleep spent in stage N1, and percentage of time asleep spent in REM, and decreased REM latency and percentage of time asleep spent in stage N3 (P<0.019). Galantamine plus buspirone given together disrupted sleep more than either drug alone, lowering sleep efficiency and percentage of time asleep spent in stage N3 and increasing awakenings, percentage of time spent awake, and percentage of time asleep spent in stage N1 (P<0.019). There was no main effect of genotype nor was there a significant multivariate interaction between genotype and drug condition.

CONCLUSION

These findings are partially consistent with the literature about sleep in depression, notably short REM latency, higher percentage of total sleep time spent in REM, lower percentage of time asleep spent in stage N3, and increased sleep fragmentation. The C/G mutation in the serotonin-1A receptor promoter region does not appear to cause noticeable differences in the sleep patterns of a relatively small sample of healthy young females. Future studies with larger sample sizes are required.

The mediator role of psychological morbidity on sleep and health behaviors in adolescents

OBJECTIVE

This study examined the mediation role of psychological morbidity, defined in this study as depression/anxiety, in the relationship between excessive daytime sleepiness and sleep quality, and between sleep habits and health behaviors, in adolescents.

METHODS

A total of 272 students, between 12 and 18 years old, underwent a psychological protocol assessing excessive daytime sleepiness, sleep quality, sleep habits, health behavior, and psychological morbidity.

RESULTS

Psychological morbidity was not associated with the relationship between excessive daytime sleepiness and sleep quality, but was associated, with statistical significance, in the relationship between sleep habits and health behaviors. These results emphasize the role of psychological morbidity in adolescent health behaviors.

CONCLUSION

Analyzing the symptoms of depression and anxiety in pediatric patients may help in a more accurate diagnosis, especially in relation to sleep problems and health behaviors.

Prospective study of predictors and consequences of insomnia: personality, lifestyle, mental health, and work-related stressors

OBJECTIVE

To prospectively investigate the reciprocal relationships between personality traits, lifestyle factors, mental health, sleepiness, and work-related stressors against insomnia.

METHODS

A total of 799 Norwegian shift-working nurses (mean age 33.2 years, 90% female) participated in this prospective cohort study. They were assessed on self-report instruments (Bergen Insomnia Scale, Diurnal Type Scale, Hospital Anxiety and Depression Scale, Negative Acts Questionnaire-Revised, Work-Family Interface Scale, among others) in 2008/2009 (wave 1) and 2011 (wave 3). Structural equation modeling was employed to investigate the bidirectional relationship between a wide range of individual and work-related variables and insomnia.

RESULTS

Languidity (β = 0.18***), anxiety (β = 0.11**), depression (β = 0.14***), exposure to bullying behavior (β = 0.08*), and negative spillover between work and family life (work to family, β = 0.08*; family to work, β = 0.07*) predicted increased symptoms of insomnia over time. Morningness (β = -0.09*) and positive spillover from work to family (β = -0.11**) predicted less symptoms of insomnia over time. No support was found for night work as a predictor of increased insomnia. Insomnia was a precursor for anxiety (β = 0.11**), but not for depression (*p <0.05, **p <0.01, ***p <0.001).

CONCLUSION

The data suggested that insomnia more often emerges as a consequence of individual and work-related factors than as a precursor to them. The scope of factors causing insomnia, and factors protecting against it, should be further investigated. Insomnia should be considered in prediction models for mental illnesses and as an outcome of adverse work-related experiences.

Social Relationships and Sleep Quality

BACKGROUND

The quality of social relationships and social support appears to be associated with physical health outcomes and sleep quality. Almost all previous research in this area focuses on positive aspects of relationships.

PURPOSE

The present study thus intended to examine the links between supportive, aversive, ambivalent, and indifferent network ties and sleep quality.

METHODS

Relationship data, Pittsburgh Sleep Quality Index (PSQI)-assessed sleep quality, and depression were examined in 175 middle-aged and older adults.

RESULTS

Consistent with hypotheses, supportive ties were positively related to sleep quality, while aversive ties predicted worse sleep quality, associations that were primarily seen for close relationships. Ambivalent and indifferent ties were not significant predictors of sleep quality. Importantly, depression was found to mediate the link between relationship quality and sleep quality.

CONCLUSIONS

These data suggest the more specific types of social relationships that may be linked to poor sleep quality and that depression appears to underlie these associations.

Increased frontal sleep slow wave activity in adolescents with major depression

Sleep slow wave activity (SWA), the major electrophysiological characteristic of deep sleep, mirrors both cortical restructuring and functioning. The incidence of Major Depressive Disorder (MDD) substantially rises during the vulnerable developmental phase of adolescence, where essential cortical restructuring is taking place. The goal of this study was to assess characteristics of SWA topography in adolescents with MDD, in order to assess abnormalities in both cortical restructuring and functioning on a local level. All night high-density EEG was recorded in 15 patients meeting DSM-5 criteria for MDD and 15 sex- and age-matched healthy controls. The actual symptom severity was assessed using the Children's Depression Rating Scale-Revised (CDRS-R). Topographical power maps were calculated based on the average SWA of the first non-rapid eye movement (NREM) sleep episode. Depressed adolescents exhibited significantly more SWA in a cluster of frontal electrodes compared to controls. SWA over frontal brain regions correlated positively with the CDRS-R subscore "morbid thoughts". Self-reported sleep latency was significantly higher in depressed adolescents compared to controls whereas sleep architecture did not differ between the groups. Higher frontal SWA in depressed adolescents may represent a promising biomarker tracing cortical regions of intense use and/or restructuring.

Opening the Debate: How to Fulfill the Need for Physicians' Training in Circadian-Related Topics in a Full Medical School Curriculum

BACKGROUND

Circadian rhythms are daily changes in our physiology and behavior that are manifested as patterns of brain wave activity, periodic hormone production, recurring cell regeneration, and other oscillatory biological activities. Their importance to human health is becoming apparent; they are deranged by shift work and jet-lag and in disparate conditions such as insomnia, sleep syndromes, coronary heart attacks, and depression, and are endogenous factors that contribute to cancer development and progression.

DISCUSSION

As evidence of the circadian connection to human health has grown, so has the number of Americans experiencing disruption of circadian rhythms due to the demands of an industrialized society. Today, there is a growing work force that experiences night shift work and time-zone shifts shaping the demands on physicians to best meet the needs of patients exposed to chronic circadian disruptions. The diverse range of illness associated with altered rhythms suggests that physicians in various fields will see its impact in their patients. However, medical education, with an already full curriculum, struggles to address this issue.

SUMMARY

Here, we emphasize the need for incorporating the topic of circadian rhythms in the medical curriculum and propose strategies to accomplish this goal.

Bidirectional relationship between sleep and optimism with depressive mood as a mediator: A longitudinal study of Chinese working adults

OBJECTIVE

Sleep and optimism are important psycho-biological and personality constructs, respectively. However, very little work has examined the causal relationship between them, and none has examined the potential mechanisms operating in the relationship. This study aimed to understand whether sleep quality was a cause or an effect of optimism, and whether depressive mood could explain the relationship.

METHOD

Internet survey data were collected from 987 Chinese working adults (63.4% female, 92.4% full-time workers, 27.0% married, 90.2% Hong Kong residents, mean age=32.59 at three time-points, spanning about 19 months). Measures included a Chinese attributional style questionnaire, the Pittsburgh Sleep Quality Index, and the Depression Anxiety Stress Scale.

RESULTS

Cross-sectional analyses revealed moderate correlations among sleep quality, depressive mood, and optimism. Cross-lagged analyses showed a bidirectional causality between optimism and sleep. Path analysis demonstrated that depressive mood fully mediated the influence of optimism on sleep quality, and it partially mediated the influence of sleep quality on optimism.

CONCLUSION

Optimism improves sleep. Poor sleep makes a pessimist. The effects of sleep quality on optimism could not be fully explained by depressive mood, highlighting the unique role of sleep on optimism. Understanding the mechanisms of the feedback loop of sleep quality, mood, and optimism may provide insights for clinical interventions for individuals presented with mood-related problems.

Sleep restriction and delayed sleep associate with psychological health and biomarkers of stress and inflammation in women

STUDY OBJECTIVES

Despite strong associations between sleep duration and health, there is no clear understanding of how volitional chronic sleep restriction (CSR) alters the physiological processes that lead to poor health in women. We focused on biochemical and psychological factors that previous research suggests are essential to uncovering the role of sleep in health.

DESIGN

Cross-sectional study.

SETTING

University-based.

PARTICIPANTS

Sixty female participants (mean age, 19.3; SD, 2.1 years).

MEASUREMENTS

We analyzed the association between self-reported volitional CSR and time to go to sleep on a series of sleep and psychological health measures as well as biomarkers of immune functioning/inflammation (interleukin [IL]-1β), stress (cortisol), and sleep regulation (melatonin).

RESULTS

Across multiple measures, poor sleep was associated with decreased psychological health and a reduced perception of self-reported physical health. Volitional CSR was related to increased cortisol and increased IL-1β levels. We separately looked at individuals who experienced CSR with and without delayed sleep time and found that IL-1β levels were significantly elevated in CSR alone and in CSR combined with a late sleep time. Cortisol, however, was only elevated in those women who experienced CSR combined with a late sleep time. We did not observe any changes in melatonin across groups, and melatonin levels were not related to any sleep measures.

CONCLUSIONS

New to our study is the demonstration of how an increase in a proinflammatory process and an increase in hypothalamic-pituitary-adrenal axis activity both relate to volitional CSR, with and without a delayed sleep time. We further show how these mechanisms relate back to psychological and self-reported health in young adult women.

The effects of galantamine and buspirone on sleep structure: Implications for understanding sleep abnormalities in major depression

RATIONALE

The serotonergic and cholinergic systems are jointly involved in regulating sleep, but this balance is theorized to be disturbed in depressed individuals.

OBJECTIVE

The goal of this study was to use biological probes in healthy participants, to model the serotonergic/cholinergic imbalance of depression and its associated abnormalities in sleep structure.

METHODS

We tested 20 healthy female participants 18-30 years of age on four non-consecutive nights. Participants were given galantamine (a cholinergic agent), buspirone (a serotonergic agonist), both drugs together, or placebo before sleeping.

RESULTS

Buspirone suppressed tonic rapid eye movement (REM): There was a significant increase in REM latency (p < 0.001). Galantamine increased tonic REM sleep, leading to more time spent in REM (p < 0.001) and shorter REM latency (p < 0.01). Galantamine and buspirone given together were not significantly different from the placebo night by REM sleep measures, but disrupted sleep more than either drug alone.

CONCLUSIONS

These findings are partially consistent with the cholinergic literature about sleep in depression, notably short REM latency, higher percentage of total sleep time spent in REM and increased sleep fragmentation. The prolonged REM latency and reduced percentage of REM with buspirone resembled the effect of selective serotonin reuptake inhibitor antidepressants on REM sleep.

A Comparison of Sleep Difficulties among Iraq/Afghanistan Theater Veterans with and without Mental Health Diagnoses

STUDY OBJECTIVES

Sleep disturbance is among the most common complaints of veterans and military personnel who deployed to the conflicts in Iraq and Afghanistan. A growing body of research has examined cross-sectional and longitudinal relationships between sleep disturbance and mental health symptoms and specific diagnoses in this population. However, prior research has not examined these relationships in terms of the presence or absence of any mental health diagnosis. The objective of the current study is to characterize the sleep complaints (sleep characteristics, sleep quality, insomnia symptoms, and distressing dreams and nightmares) of previously deployed military personnel in terms of the presence or absence of a mental health disorder, diagnosed using structured clinical diagnostic interviews.

METHODS

Participants (n = 1,238) were veterans and active duty military personnel serving in the military since September 11, 2001, and deployed at least once. Scale scores and item-level data from the Pittsburgh Sleep Quality Index (PSQI), the PSQI-Addendum, the Davidson Trauma Scale, and the Symptom Checklist-90 were used to compare sleep across mental health status (with/without mental health disorder).

RESULTS

As expected, self-reported sleep impairments were worse among those meeting criteria for a mental health disorder. However, findings also revealed very poor sleep among those without a mental health diagnosis as well. Mean values for both groups were suggestive of short sleep duration, low sleep efficiency, long sleep onset latencies, poor sleep quality, frequent insomnia symptoms, and nightmare frequencies that are well above norms for the general population.

CONCLUSIONS

Given the evidence for adverse mental and physical health sequelae of untreated sleep disturbance, increased attention to sleep in this population may serve as a primary prevention strategy.

24-HOUR ACTIVITY RHYTHM AND SLEEP DISTURBANCES IN DEPRESSION AND ANXIETY: A POPULATION-BASED STUDY OF MIDDLE-AGED AND OLDER PERSONS

BACKGROUND

Disturbed circadian rhythms have been associated with depression and anxiety, but it is unclear if disturbances in the 24-hr activity rhythm and sleep are independently and specifically related to these disorders.

METHODS

In 1,714 middle-aged and elderly participants of the Rotterdam Study, we collected actigraphy recordings of at least 96 hr (138 ± 14 hr, mean ± standard deviation). Activity rhythms were quantified calculating the fragmentation of the rhythm, stability of the rhythm over days, and timing of the rhythm. Total sleep time, sleep onset latency, and wake after sleep onset were also estimated with actigraphy. Depressive symptoms were assessed with the Center for Epidemiologic Studies Depression scale, persons with clinically relevant depressive symptoms were interviewed to diagnose DSM-IV-depressive disorder. Anxiety disorders were determined with the Munich version of the Composite International Diagnostic Interview.

RESULTS

More fragmented rhythms were associated with clinically relevant depressive symptoms (odds ratio (OR): 1.27, 95% confidence interval (CI): 1.04;1.54) and anxiety disorders (OR: 1.39, 95% CI: 1.14;1.70) after covariate adjustment. Less stable rhythms, longer sleep onset latency, and more wake after sleep onset were related to clinically relevant depressive symptoms or anxiety disorders only if not adjusted for covariates and other activity rhythm and sleep indicators.

CONCLUSIONS

Our study in middle-aged and elderly persons suggests that fragmentation of the 24-hr activity rhythm is associated with depression and anxiety. Moreover, this association also largely accounts for the effect of disturbed sleep on these psychiatric disorders.

Sleep spindle and K-complex detection using tunable Q-factor wavelet transform and morphological component analysis

A novel framework for joint detection of sleep spindles and K-complex events, two hallmarks of sleep stage S2, is proposed. Sleep electroencephalography (EEG) signals are split into oscillatory (spindles) and transient (K-complex) components. This decomposition is conveniently achieved by applying morphological component analysis (MCA) to a sparse representation of EEG segments obtained by the recently introduced discrete tunable Q-factor wavelet transform (TQWT). Tuning the Q-factor provides a convenient and elegant tool to naturally decompose the signal into an oscillatory and a transient component. The actual detection step relies on thresholding (i) the transient component to reveal K-complexes and (ii) the time-frequency representation of the oscillatory component to identify sleep spindles. Optimal thresholds are derived from ROC-like curves (sensitivity vs. FDR) on training sets and the performance of the method is assessed on test data sets. We assessed the performance of our method using full-night sleep EEG data we collected from 14 participants. In comparison to visual scoring (Expert 1), the proposed method detected spindles with a sensitivity of 83.18% and false discovery rate (FDR) of 39%, while K-complexes were detected with a sensitivity of 81.57% and an FDR of 29.54%. Similar performances were obtained when using a second expert as benchmark. In addition, when the TQWT and MCA steps were excluded from the pipeline the detection sensitivities dropped down to 70% for spindles and to 76.97% for K-complexes, while the FDR rose up to 43.62 and 49.09%, respectively. Finally, we also evaluated the performance of the proposed method on a set of publicly available sleep EEG recordings. Overall, the results we obtained suggest that the TQWT-MCA method may be a valuable alternative to existing spindle and K-complex detection methods. Paths for improvements and further validations with large-scale standard open-access benchmarking data sets are discussed.

Effects of a Multi-Component Behavioral Intervention (MCI) for Insomnia on Depressive and Insomnia Symptoms in Individuals with High and Low Depression

Insomnia and depression are prevalent and co-occurring conditions that are associated with significant impairment of life. Previous research indicates that cognitive-behavioral interventions for insomnia (CBT-I) can improve both insomnia and depressive symptoms. The aim of the authors in this study was to determine whether a multi-component behavioral intervention (MCI) improved both insomnia and depressive symptoms in persons presenting with insomnia and high levels of depression. The sample consisted of 321 individuals with insomnia who participated in a trial of insomnia treatments; 106 participants had high levels of depression (score ≥ 16 on CES-D) at baseline. Participants either received the MCI or a control treatment (sleep education and hygiene booklet). At post-test, participants with high and low levels of depressive symptoms showed significant improvement in insomnia symptoms. Those with high depression also had significant reductions in depressive symptoms. It can be concluded that for individuals with depression and insomnia, CBT-I is a viable intervention for managing depressive symptoms, which complements other approaches for treating depression.

Glial dysfunction in the mouse habenula causes depressive-like behaviors and sleep disturbance

The lateral habenula (LHb) regulates the activity of monoaminergic neurons in the brainstem. This area has recently attracted a surge of interest in psychiatry because studies have reported the pathological activation of the habenula in patients with major depression and in animal models. The LHb plays a significant role in the pathophysiology of depression; however, how habenular neurons are activated to cause various depression symptoms, such as reduced motivation and sleep disturbance, remain unclear. We hypothesized that dysfunctional astrocytes may cause LHb hyperactivity due to the defective uptake activity of extracellular glutamate, which induces depressive-like behaviors. We examined the activity of neurons in habenular pathways and performed behavioral and sleep analyses in mice with pharmacological and genetic inhibition of the activity of the glial glutamate transporter GLT-1 in the LHb. The habenula-specific inhibition of GLT-1 increased the neuronal firing rate and the level of c-Fos expression in the LHb. Mice with reduced GLT-1 activity in the habenula exhibited a depressive-like phenotype in the tail suspension and novelty-suppressed feeding tests. These animals also displayed increased susceptibility to chronic stress, displaying more frequent avoidant behavior without affecting locomotor activity in the open-field test. Intriguingly, the mice showed disinhibition of rapid eye movement sleep, which is a characteristic sleep pattern in patients with depression. These results provide evidence that disrupting glutamate clearance in habenular astrocytes increases neuronal excitability and depressive-like phenotypes in behaviors and sleep.

The effects of ethnic/racial discrimination and sleep quality on depressive symptoms and self-esteem trajectories among diverse adolescents

Ethnic/racial discrimination has persistent negative implications for both physical and mental health. The current study employs a risk and resilience framework to explore the joint effects of ethnic/racial discrimination and sleep disturbance on psychosocial outcomes among adolescents. In a sample of 146 minority and White adolescents (70% female), changes in depressive symptoms, anxiety, and self-esteem over 3 years are explored using growth curve models. Regardless of ethnic background, adolescents reporting high levels of ethnic/racial discrimination and poor sleep also reported a corresponding increase in depressive symptoms and lower levels of self-esteem over time. Adolescents reporting all other combinations of sleep quality and ethnic/racial discrimination reported more positive adjustment over time. The joint effects of sleep and ethnic/racial discrimination on adolescent psychosocial development are discussed.

Interaction between 5-HTTLPR genotype and cognitive stress vulnerability on sleep quality: effects of sub-chronic tryptophan administration

BACKGROUND

Abundant evidence suggests that allelic variation in the serotonin transporter-linked polymorphic region (5-HTTLPR) influences susceptibility to stress and its affective consequences due to brain serotonergic vulnerability. Based on recent assumptions, the present study examined whether the 5-HTTLPR genotype may also interact with a vulnerability to chronic stress experience (conceptualized by trait neuroticism) in order to influence sleep quality and, additionally, whether this is influenced by brain serotonergic manipulations.

METHODS

In a well-balanced experimental design, homozygous S-allele (n = 57) and L-allele (n = 54) genotypes with high and low chronic stress vulnerability (neuroticism) were first assessed for general past sleep quality during a month before onset of the experiment. Then subjects were assessed for sleep quality following 7 days of tryptophan (3.0g/day) or placebo intake.

RESULTS

Although high neuroticism was significantly related to a higher frequency of stressful life events and daily hassles, it did not interact with the 5-HTTLPR genotype on general past sleep quality. However, as expected, a 7 day period of tryptophan administration was exclusively associated with better sleep quality scores in the S'/S' genotype with high trait neuroticism.

CONCLUSIONS

Current findings suggest that 5-HTTLPR does not directly interact with stress vulnerability in order to influence sleep quality. Instead, based on current and previous findings, it is suggested that the S'/S' 5-HTTLPR genotype promotes the risk for stress-related sleep disturbances because of an increased susceptibility to the depressogenic consequences of stress. Accordingly, by way of reducing depressive symptomatology, tryptophan augmentation may particularly improve sleep quality in stress-vulnerable individuals carrying the 5-HTTLPR S-allele.

REM sleep and memory reorganization: Potential relevance for psychiatry and psychotherapy

Sleep can foster the reorganization of memory, i.e. the emergence of new memory content that has not directly been encoded. Current neurophysiological and behavioral evidence can be integrated into a model positing that REM sleep particularly promotes the disintegration of existing schemas and their recombination in the form of associative thinking, creativity and the shaping of emotional memory. Particularly, REM sleep related dreaming might represent a mentation correlate for the reconfiguration of memory. In a final section, the potential relevance for psychiatry and psychotherapy is discussed.

Linking emotional distress to unhealthy sleep duration: analysis of the 2009 National Health Interview Survey

OBJECTIVE

The objective of the study was to examine the independent association of emotional distress with unhealthy sleep duration (defined as <7 or >8 hours).

METHODS

Data from the 2009 National Health Interview Survey (NHIS), a cross-sectional household survey, were analyzed to investigate the associations of emotional distress with unhealthy sleep durations, adjusting for sociodemographic factors, health risks, and chronic diseases through hierarchical multiple logistic regression analysis.

PARTICIPANTS

A total of 27,731 participants (age range 18-85 years) from the NHIS 2009 dataset were interviewed.

MEASURES

Unhealthy sleep duration is defined as sleep duration <7 or >8 hours, whereas healthy sleep is defined as sleep duration lasting for 7-8 hours. Emotional distress is based on the Kessler 6 Non-Specific Distress Battery, which assesses the frequency of feeling sad, nervous, restless, hopeless, worthless, and burdened, over a 30-day period.

RESULTS

Of the sample, 51.7% were female; 83.1% were white and 16.9% were black. Eleven percent experienced emotional distress and 37.6% reported unhealthy sleep. Adjusted logistic regression analysis revealed that individuals with emotional distress had 55% greater odds of reporting unhealthy sleep (odds ratio [OR] =1.55, 95% confidence interval [CI] =1.42, 1.68, P<0.001).

CONCLUSION

Emotional distress, an important proxy for poor psychological health, was a significant predictor of unhealthy sleep, independent of the influences of several factors including demographic (age, education, sex, race/ethnicity, and family income), health risks (alcohol consumption and smoking status), and chronic diseases/conditions (diabetes, obesity, hypertension, heart disease, cancer, and arthritis).

Association between depressive symptoms and changes in sleep condition in the grieving process

PURPOSE

Bereaved families often suffer from insomnia and depression. However, the associations between depressive state and changes in sleep condition during the grieving process have not been investigated. This study aimed to clarify the prevalence of insomnia symptoms and to explore associations between present depressive state and changes in sleep condition in the grieving process in bereaved families of Japanese patients with cancer.

METHODS

A cross-sectional, multicenter survey was conducted in 103 certified palliative care units. A questionnaire asking insomnia symptoms and depressive symptoms by the Center for Epidemiological Studies Depression Scale (CES-D) was mailed to bereaved families (N = 987). The association between present depressive state (CES-D ≥7) and sleep conditions in the grieving process were analyzed.

RESULTS

A total of 561 families were enrolled for analysis. Fifty-three percent of family members were considered to be in a depressive state at the time of the investigation. Prevalence of past insomnia was 86.5% at "within a few weeks before the patient's death" (T1) and 84.5% at "within 6 months after the patient's death" (T2) in all bereaved family members. However, in contrast to decreased severity of insomnia between T1 and T2 in the non-depressive group (p < 0.05), severity of insomnia was unchanged in the depressive group during this period (p = 0.139).

CONCLUSIONS

Insomnia symptoms are highly prevalent and may be associated with posthumous depressive state in bereaved Japanese families. These results suggest the need for careful observation of changes in sleep condition during the grieving process.

Chronic escitalopram treatment attenuated the accelerated rapid eye movement sleep transitions after selective rapid eye movement sleep deprivation: a model-based analysis using Markov chains

Background

Shortened rapid eye movement (REM) sleep latency and increased REM sleep amount are presumed biological markers of depression. These sleep alterations are also observable in several animal models of depression as well as during the rebound sleep after selective REM sleep deprivation (RD). Furthermore, REM sleep fragmentation is typically associated with stress procedures and anxiety. The selective serotonin reuptake inhibitor (SSRI) antidepressants reduce REM sleep time and increase REM latency after acute dosing in normal condition and even during REM rebound following RD. However, their therapeutic outcome evolves only after weeks of treatment, and the effects of chronic treatment in REM-deprived animals have not been studied yet.

Results

Chronic escitalopram- (10 mg/kg/day, osmotic minipump for 24 days) or vehicle-treated rats were subjected to a 3-day-long RD on day 21 using the flower pot procedure or kept in home cage. On day 24, fronto-parietal electroencephalogram, electromyogram and motility were recorded in the first 2 h of the passive phase. The observed sleep patterns were characterized applying standard sleep metrics, by modelling the transitions between sleep phases using Markov chains and by spectral analysis.

Based on Markov chain analysis, chronic escitalopram treatment attenuated the REM sleep fragmentation [accelerated transition rates between REM and non-REM (NREM) stages, decreased REM sleep residence time between two transitions] during the rebound sleep. Additionally, the antidepressant avoided the frequent awakenings during the first 30 min of recovery period. The spectral analysis showed that the SSRI prevented the RD-caused elevation in theta (5–9 Hz) power during slow-wave sleep. Conversely, based on the aggregate sleep metrics, escitalopram had only moderate effects and it did not significantly attenuate the REM rebound after RD.

Conclusion

In conclusion, chronic SSRI treatment is capable of reducing several effects on sleep which might be the consequence of the sub-chronic stress caused by the flower pot method. These data might support the antidepressant activity of SSRIs, and may allude that investigating the rebound period following the flower pot protocol could be useful to detect antidepressant drug response. Markov analysis is a suitable method to study the sleep pattern.

The impact of sleep, stress, and depression on postpartum weight retention: a systematic review

OBJECTIVE

To review the impact of sleep, stress, and/or depression on postpartum weight retention.

METHODS

We searched three electronic databases, PubMed, ISI Web of Science, and PsycInfo. Studies were included if they were published between January 1990 and September 2013 in English, measured sleep, stress, and/or depression in the postpartum period, and assessed the association of these factors with postpartum weight retention. Two reviewers reviewed included articles and rated study quality using a modified version of the Downs and Black scale.

RESULTS

Thirteen studies met our pre-defined eligibility criteria, reporting on 9 study samples. Two were cross-sectional studies and eleven were longitudinal studies. The study sample size ranged from 74 to 37,127. All four studies examining short sleep duration and postpartum weight retention reported a positive association. The four studies examining postpartum stress and weight retention reported non-significant associations only. Of 7 studies examining postpartum depression and weight retention, 3 reported non-significant associations, and 4 reported positive associations.

CONCLUSION

Research investigating the impact of postpartum sleep, stress, depression on weight retention is limited. Future longitudinal studies are needed.

A change in sleep pattern may predict Alzheimer disease

OBJECTIVE

Sleep problems may adversely affect neuronal health. We examined a subjective report of change (reduced duration and/or depth) in sleep pattern in relation to subsequent risk of incident all-cause dementia and Alzheimer disease (AD) over 9 years.

METHODS

This longitudinal study used data from a population-based sample of 214 Swedish adults aged 75 and over who were dementia-free both at baseline and at first follow-up (3 years later). The sample was 80% female and, on average, 83.4 years of age at baseline. All participants underwent a thorough clinical examination to ascertain all-cause dementia and AD.

RESULTS

Forty percent of participants reported a change in sleep duration at baseline. Between the 6th and 9th year after baseline, 28.5% were diagnosed with all-cause dementia, 22.0% of whom had AD. Reduced sleep was associated with a 75% increased all-cause dementia risk (hazard ratio: 1.75; 95% confidence interval: 1.04-2.93; Wald = 4.55, df = 1, p = 0.035) and double the risk of AD (hazard ratio: 2.01; 95% confidence interval: 1.12-3.61; Wald = 5.47, df = 1, p = 0.019) after adjusting for age, gender, and education. The results remained after adjusting for lifestyle and vascular factors but not after adjusting for depressive symptoms. No evidence supported a moderating effect of the use of sleeping pills, and the sleep-dementia relationship remained after controlling for the presence of the apolipoprotein E ε4 allele.

CONCLUSION

Self-reported sleep problems may increase the risk for dementia, and depressive symptoms may explain this relationship. Future research should determine whether treatment, in particular, behavioral or nonpharmacologic treatment, may represent one avenue toward reduction of dementia risk in late life.

Repeated exposure to conditioned fear stress increases anxiety and delays sleep recovery following exposure to an acute traumatic stressor

Repeated stressor exposure can sensitize physiological responses to novel stressors and facilitate the development of stress-related psychiatric disorders including anxiety. Disruptions in diurnal rhythms of sleep-wake behavior accompany stress-related psychiatric disorders and could contribute to their development. Complex stressors that include fear-eliciting stimuli can be a component of repeated stress experienced by human beings, but whether exposure to repeated fear can prime the development of anxiety and sleep disturbances is unknown. In the current study, adult male F344 rats were exposed to either control conditions or repeated contextual fear conditioning for 22 days followed by exposure to no, mild (10), or severe (100) acute uncontrollable tail shock stress. Exposure to acute stress produced anxiety-like behavior as measured by a reduction in juvenile social exploration and exaggerated shock-elicited freezing in a novel context. Prior exposure to repeated fear enhanced anxiety-like behavior as measured by shock-elicited freezing, but did not alter social exploratory behavior. The potentiation of anxiety produced by prior repeated fear was temporary; exaggerated fear was present 1 day but not 4 days following acute stress. Interestingly, exposure to acute stress reduced rapid eye movement (REM) and non-REM (NREM) sleep during the hours immediately following acute stress. This initial reduction in sleep was followed by robust REM rebound and diurnal rhythm flattening of sleep/wake behavior. Prior repeated fear extended the acute stress-induced REM and NREM sleep loss, impaired REM rebound, and prolonged the flattening of the diurnal rhythm of NREM sleep following acute stressor exposure. These data suggest that impaired recovery of sleep/wake behavior following acute stress could contribute to the mechanisms by which a history of prior repeated stress increases vulnerability to subsequent novel stressors and stress-related disorders.

[Insomnia--state of the science]

Diagnostic systems such as the international classification of diseases (ICD-10) or the diagnostic and statistical manual of mental disorders (DSM IV) have frequently been criticized as not adequately reflecting the complexity and heterogeneity of insomnia. Progress was made through the introduction of the international classification of sleep disorders (ICSD-2) and the research diagnostic criteria (RDC). The DSM-5 introduced the new category of insomnia disorder, thus relinquishing the traditional dichotomy of primary versus secondary insomnia. Recent basic research indicates that genetic and epigenetic factors are involved in the etiology of insomnia; the so-called three P model (i.e. predisposing, precipitating and perpetuating factors) and the hyperarousal concept have gained much attention in trying to explain the pathophysiology of insomnia. With respect to the cognitive-behavioral therapy of insomnia (CBT-I), a plethora of empirical evidence supports the first-line character of this type of treatment for insomnia. Unfortunately, CBT-I is still administered to only a minority of afflicted patients, probably due to a lack of resources in the healthcare system. As a consequence, stepped-care models to improve insomnia therapy encompass self-help programs, internet-based treatment avenues, community-centered activities (specially trained nurses) and as a last resort medical specialists/psychotherapists and sleep experts to deal with insomnia.