Effects of REM sleep during a daytime nap on emotional perception in individuals with and without depression

Sociodemographic predictors of the association between self-reported sleep duration and depression

A growing interest has been recently reported in exploring sleep duration within psychology context in particular to its relation to some mental chronic diseases such as depression. The aim of this study is to investigate the association between self-reported sleep hours as an outcome and self-perceived depression among Emirati adults, after adjusting for sociodemographic factors such as age, gender, marital status, and employment status. We performed a cross-sectional analysis using 11,455 participants baseline data of the UAE Healthy Future Study (UAEHFS). Univariate and multivariate logistic regression models were performed with self-reported sleep hours as an outcome. The predictors were the self-reported depression by measuring the PHQ-8 score, sociodemographic factors (age, gender, marital status, and employment status) Odds ratios with 95% confidence intervals (CI) were reported. In a sensitivity analysis, a multivariate imputation by chained equations (MICE) procedure was applied with classification and Regression Trees (CART) to impute missing values. Overall, 11,455 participants were included in the final analysis of this study. Participants' median age was 32.0 years (Interquartile-Range: 24.0, 39.0). There were 6,217 (54.3%) males included in this study. In total, 4,488 (63.6%) of the participants reported sleep duration of more than 7 hours. Statistically significant negative association was observed between the total PHQ-8 score as a measure for depression and binarized self-reported sleep, OR = 0.961 (95% CI: 0.948, 0.974). For one unit increase in age and BMI, the odds ratio of reporting shorter sleep was 0.979 (95% CI: 0.969, 0.990) and 0.987 (95% CI: 0.977, 0.998), respectively. The study findings indicate a correlation between self-reported depression and an increased probability of individuals reporting shorter self-perceived sleep durations especially when considering the sociodemographic factors as predictors. There was a variation in the effect of depression on sleep duration among different study groups. In particular, the association between reported sleep duration and reported depression, students and unemployed individuals have reported longer sleep hours as compared to employed participants. Also, married individuals reported a higher percentage of longer sleep duration as compared to single and unmarried ones when examined reported depression as a predictor to sleep duration. However, there was no gender differences in self-perceived sleep duration when associated with reported depression.

Overnight neuronal plasticity and adaptation to emotional distress

Expressions such as 'sleep on it' refer to the resolution of distressing experiences across a night of sound sleep. Sleep is an active state during which the brain reorganizes the synaptic connections that form memories. This Perspective proposes a model of how sleep modifies emotional memory traces. Sleep-dependent reorganization occurs through neurophysiological events in neurochemical contexts that determine the fates of synapses to grow, to survive or to be pruned. We discuss how low levels of acetylcholine during non-rapid eye movement sleep and low levels of noradrenaline during rapid eye movement sleep provide a unique window of opportunity for plasticity in neuronal representations of emotional memories that resolves the associated distress. We integrate sleep-facilitated adaptation over three levels: experience and behaviour, neuronal circuits, and synaptic events. The model generates testable hypotheses for how failed sleep-dependent adaptation to emotional distress is key to mental disorders, notably disorders of anxiety, depression and post-traumatic stress with the common aetiology of insomnia.

Interventions for deficits in recognition of emotions in facial expressions in major depressive disorder: An updated systematic review of clinical trials

The recognition of emotions in facial expressions (REFE) is a core construct of social cognition. In the last decades, studies have showed that REFE is altered in major depressive disorder (MDD), but the evidence is conflicting. Thus, we conducted a systematic review of clinical trials involving therapeutic interventions in MDD and any evaluation of REFE to update (2018-2023) and systematically evaluate the evidence derived from controlled clinical trials on the effects of therapeutic strategies to MDD on the REFE. Eleven studies were included in the final review. Some interventions, including drugs (ketamine, bupropion, psylocibin) and non-pharmacological strategies (psychotherapy) seem to be able to reduce pre-existing REFE biases in MDD patients. However, there was a high heterogeneity in the evaluated studies, in terms of sample, interventions, tasks and results. Further studies and more consistent evaluation tools are highly needed to better understand nuanced deficits and specific actions of different treatment options.

Inman C, Shahawy OE, Weitzman M, Schmidt AM, Sherman S, Abdulle A, Ahmad A, Ali R. Association between depression, happiness, and sleep duration: data from the UAE healthy future pilot study

BACKGROUND

The United Arab Emirates Healthy Future Study (UAEHFS) is one of the first large prospective cohort studies and one of the few studies in the region which examines causes and risk factors for chronic diseases among the nationals of the United Arab Emirates (UAE). The aim of this study is to investigate the eight-item Patient Health Questionnaire (PHQ-8) as a screening instrument for depression among the UAEHFS pilot participants.

METHODS

The UAEHFS pilot data were analyzed to examine the relationship between the PHQ-8 and possible confounding factors, such as self-reported happiness, and self-reported sleep duration (hours) after adjusting for age, body mass index (BMI), and gender.

RESULTS

Out of 517 participants who met the inclusion criteria, 487 (94.2%) participants filled out the questionnaire and were included in the statistical analysis using 100 multiple imputations. 231 (44.7%) were included in the primary statistical analysis after omitting the missing values. Participants' median age was 32.0 years (Interquartile Range: 24.0, 39.0). In total, 22 (9.5%) of the participant reported depression. Females have shown significantly higher odds of reporting depression than males with an odds ratio = 3.2 (95% CI:1.17, 8.88), and there were approximately 5-fold higher odds of reporting depression for unhappy than for happy individuals. For one interquartile-range increase in age and BMI, the odds ratio of reporting depression was 0.34 (95% CI: 0.1, 1.0) and 1.8 (95% CI: 0.97, 3.32) respectively.

CONCLUSION

Females are more likely to report depression compared to males. Increasing age may decrease the risk of reporting depression. Unhappy individuals have approximately 5-fold higher odds of reporting depression compared to happy individuals. A higher BMI was associated with a higher risk of reporting depression. In a sensitivity analysis, individuals who reported less than 6 h of sleep per 24 h were more likely to report depression than those who reported 7 h of sleep.

Preferential consolidation of emotional reactivity during sleep: A systematic review and meta-analysis

Many studies have investigated whether sleep affects cognitively unmodulated reactivity to emotional stimuli. These studies operationalize emotion regulation by using subjective and/or objective measures to compare pre- and post-sleep reactivity to the same emotional stimuli. Findings have been inconsistent: some show that sleep attenuates emotional reactivity, whereas others report enhanced or maintained reactivity. Across-study methodological differences may account for discrepant findings. To resolve the questions of whether sleep leads to the attenuation, enhancement, or maintenance of emotional reactivity, and under which experimental conditions particular effects are observed, we undertook a synthesized narrative and meta-analytic approach. We searched PubMed, PsycINFO, PsycARTICLES, Web of Science, and Cochrane Library databases for relevant articles, using search terms determined a priori and search limits of language = English, participants = human, and dates = January 2006–June 2021. Our final sample included 24 studies that investigated changes in emotional reactivity in response to negatively and/or positively valenced material compared to neutral material over a period of sleep compared to a matched period of waking. Primary analyses used random effects modeling to investigate whether sleep preferentially modulates reactivity in response to emotional stimuli; secondary analyses examined potential moderators of the effect. Results showed that sleep (or equivalent periods of wakefulness) did not significantly affect psychophysiological measures of reactivity to negative or neutral stimuli. However, self-reported arousal ratings of negative stimuli were significantly increased post-sleep but not post-waking. Sub-group analyses indicated that (a) sleep-deprived participants, compared to those who slept or who experienced daytime waking, reacted more strongly and negatively in response to positive stimuli; (b) nap-exposed participants, compared to those who remained awake or who slept a full night, rated negative pictures less negatively; and (c) participants who did not obtain substantial REM sleep, compared to those who did and those exposed to waking conditions, had attenuated reactivity to neutral stimuli. We conclude that sleep may affect emotional reactivity, but that studies need more consistency in methodology, commitment to collecting both psychophysiological and self-report measures, and should report REM sleep parameters. Using these methodological principles would promote a better understanding of under which conditions particular effects are observed.

Effect of napping on a bean bag chair on sleep stage, muscle activity, and heart rate variability

Background

Although ample evidence has demonstrated that daytime napping is beneficial for health and cognitive performance, bedding for napping has not yet been scientifically investigated.

Objectives

To explore the effect of a bean bag chair on daytime napping and physiological parameters related to sleep.

Methods

Fourteen healthy participants were enrolled within the context of a randomized, single-blind, crossover study to evaluate the effects of a bean bag chair in comparison with those of a urethane chair manufactured to have a similar shape. Electroencephalogram, electromyogram, and heart rate variability were recorded and compared between wakefulness and napping.

Results

Electroencephalogram analyses revealed no significant differences in sleep architecture or frequency components; however, a significant decrease was found in electromyogram recordings in the trapezius muscle, which represents the neck region (p = 0.019). Additionally, a significant main effect of bedding in the low-frequency/high-frequency ratio (F[1,20] = 4.314, p = 0.037) was revealed.

Conclusions

These results suggest that napping in a bean bag chair may provide a comfortable napping environment involving muscle relaxation and proper regulation of the autonomic nervous function.

Sleep and Inhibitory Control Over Mood-Congruent Information in Emerging Adults With Depressive Disorder

OBJECTIVE

Accumulating evidence has suggested bidirectionality between sleep problems and depression, but the underlying mechanism is unclear. We assessed the role of sleep in inhibitory control ability with emotional stimuli, which has been shown to be suboptimal among individuals with depression and proposed to perpetuate depressive symptoms.

METHODS

Emerging adults (aged 18-25 years, 64.6% female) were screened for depressive and other mental disorders by structured clinical interview and questionnaire. Individuals with depressive disorders were assigned to have a polysomnography-monitored daytime sleep opportunity (Sleep-Dep, n = 20), whereas nondepressed individuals were randomized to either have daytime sleep (Sleep-Ctrl, n = 27) or stay awake (Wake-Ctrl, n = 18). Participants completed the Affective Go/No-Go Task two times, separated by experimental conditions.

RESULTS

A factorial model with a between-subject factor (Sleep-Dep/Sleep-Ctrl/Wake-Ctrl) and a within-subject factor (test 1/test 2) was used to assess if the groups differed in inhibitory control across test sessions, as inferred by changes in d-prime and false alarm rates (FA). Results from mixed factorial models showed a significant interaction effect between time and group on FA in the block with neutral faces as the target and happy faces as the nontarget (F(2,61) = 5.15, pfdr = .045). Although Sleep-Dep had decreased FA after sleep (t(19) = 2.94, pfdr = .050), Sleep-Ctrl and Wake-Ctrl had no significant between-session changes (p values > .05). Postsleep improvement in FA in Sleep-Dep correlated with longer stage 2 sleep (r(20) = 0.788, pfdr < .001) and stage 2 fast spindle number at O1 (r(18) = 0.692, pfdr = .015).

CONCLUSIONS

Sleep gain, particularly stage 2 sleep and related physiology, potentially enhances inhibitory control ability responding to emotional information among individuals with depressive disorders.

Go to Bed and You MIGHT Feel Better in the Morning—the Effect of Sleep on Affective Tone and Intrusiveness of Emotional Memories

Purpose of Review

It is important to examine what effect sleep has after an emotional experience. More knowledge about this topic could help inform us whether there are any potential sleep interventions that could help make sure that memories of negative emotional experiences are processed in the most adaptive manner possible.

Recent Findings

Findings on the role of sleep in altering reactivity to emotional stimuli have been highly varied, with significant findings in opposite directions. A new exciting development in the field is several studies finding that sleep seems to make memories of negative experiences less intrusive.

Summary

This review has mainly aimed to give an overview of the field, and of which issues need to be resolved. We argue for there being a strong need for standardization of how data are analyzed and presented, as well as for better methods for determining to what extent the effects of sleep are specific for a particular memory, or represent general changes in emotional reactivity.