REM sleep dysregulation in depression: state of the art

REM density predicts rapid antidepressant response to ketamine in individuals with treatment-resistant depression

Abnormalities during rapid eye movement (REM) sleep contribute to the pathophysiology of major depressive disorder (MDD), but few studies have explored the relationship between REM sleep and treatment-resistant depression (TRD). In MDD, REM sleep abnormalities often manifest as alterations in total night REM Density (RD), RD in the first REM period (RD1), and REM Latency (RL). Among these, RD1 is notably considered a potential endophenotype of depression. This study compared REM sleep markers between 63 drug-free individuals with TRD (39 F/24 M) and 41 healthy volunteers (25 F/16 M). It also investigated the effects of ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, on these REM sleep variables. Specifically, the study investigated whether RD1 could predict antidepressant response to ketamine. TRD participants showed higher RD1 and shorter RL at baseline compared to HVs, as assessed via non-parametric tests, but Total Night RD did not differ between the two groups. Ketamine treatment decreased RD1 in TRD participants but did not affect Total Night RD or RL. As assessed via the Support Vector Machine (SVM) algorithm, baseline RD1 level moderately predicted antidepressant response to ketamine versus non-response (area under the receiver operating characteristic (ROC) curve (AUC) = 0.73, with a median accuracy of 0.75), wherein TRD participants with higher baseline RD1 were more likely to respond to ketamine. These results underscore the utility of RD1 for identifying individuals most likely to benefit from ketamine treatment, enabling more targeted and effective therapeutic strategies. Clinical Trials Identifier: NCT00088699, NCT01204918.

The impact of childhood emotional abuse and depressive symptoms on sleep macro-architecture and cortical thickness

BACKGROUND

Adverse childhood events and especially emotional abuse (EA) is consistently associated with poor psychiatric outcomes in adulthood, with depressive symptoms being one of the most prevalent. Both EA and depression are frequently associated with poorer sleep quality and cortical structural abnormalities. Interestingly, some individuals who experienced early-life EA are resilient against the development of psychiatric illness in adulthood and are believed to possess distinct neurobiology that confer more effective coping mechanisms.

METHODS

682 subjects from a population-based cohort underwent polysomnography (PSG), whole-body magnetic resonance imaging (MRI) and completed the Childhood Trauma Questionnaire (CTQ) and Patient Health Questionnaire (PHQ-9). Linear regressions were used to model joint EA and depressive symptoms effects with sleep macro-architecture and cortical thickness; and path analyses were used to investigate mediation effects.

RESULTS

Considering depressive symptoms as a product variable with EA (EA×depression), we observed the strongest effect in EA×depression with percentage spent in SWS (%SWS), where %SWS increased with EA in non-depressed subjects. We observed increased thicknesses in three cortical regions in emotionally-abused, non-depressed individuals from structural MRI. Mediation analysis demonstrated that %SWS significantly mediated the association of EA×depression with cortical thickness in two of the three regions.

LIMITATIONS

We are not able to infer any causal role of sleep in our cross-sectional design. Self-report questionnaires are also subject to recall-bias.

CONCLUSIONS

Higher regional cortical thicknesses in emotionally-abused, non-depressed individuals can partially be explained by increased %SWS, suggesting a potentially protective role of SWS against brain volume loss associated with EA and depression.

Subclinically Depressed Individuals Showed Less Trust after a Night of Sleep Deprivation

Insufficient sleep's impact on cognitive and emotional function is well-documented, but its effects on social functioning remain understudied. This research investigates the influence of depressive symptoms on the relationship between sleep deprivation (SD) and social decision-making. Forty-two young adults were randomly assigned to either the SD or sleep control (SC) group. The SD group stayed awake in the laboratory, while the SC group had a normal night's sleep at home. During the subsequent morning, participants completed a Trust Game (TG) in which a higher monetary offer distributed by them indicated more trust toward their partners. They also completed an Ultimatum Game (UG) in which a higher acceptance rate indicated more rational decision-making. The results revealed that depressive symptoms significantly moderated the effect of SD on trust in the TG. However, there was no interaction between group and depressive symptoms found in predicting acceptance rates in the UG. This study demonstrates that individuals with higher levels of depressive symptoms display less trust after SD, highlighting the role of depressive symptoms in modulating the impact of SD on social decision-making. Future research should explore sleep-related interventions targeting the psychosocial dysfunctions of individuals with depression.

World Sleep Society recommendations for the use of wearable consumer health trackers that monitor sleep

Wearable consumer health trackers (CHTs) are increasingly used for sleep monitoring, yet their utility remains debated within the sleep community. To navigate these perspectives, we propose pragmatic, actionable recommendations for users, clinicians, researchers, and manufacturers to support CHT usage and development. We provide an overview of the evolution of multi-sensor CHTs, detailing common sensors and sleep-relevant metrics. We advocate for standardized 'fundamental sleep measures' across manufacturers, distinguishing these from proprietary exploratory metrics with future potential. We outline best practices for using CHT-derived sleep data in healthy individuals while addressing current device limitations. Additionally, we explore their role in evaluating and managing individuals at risk for or diagnosed with insomnia, sleep apnea, or circadian rhythm sleep-wake disorders. Guidance is provided on device selection to align with their intended use and on conducting and interpreting performance evaluation studies. Collaboration with manufacturers is needed to balance feature comprehensiveness with clinical utility and usability. Finally, we examine challenges in integrating heterogeneous sleep data into clinical health records and discuss medical device certification for specific wearable CHT features. By addressing these issues, our recommendations aim to inform the usage of CHTs in the global community and to begin bridging the gap between consumer technology and clinical application, maximizing the potential of CHTs to enhance both personal and community sleep health.

Long sleep duration, cognitive performance, and the moderating role of depression: A cross-sectional analysis in the Framingham Heart Study

INTRODUCTION

We investigated whether depression modified the associations between sleep duration and cognitive performance.

METHODS

We examined the associations between sleep duration and cognition in 1853 dementia-and-stroke-free participants (mean age 49.8 years, [range 27-85]; 42.7% male). Participants were categorized into four groups: no depressive symptoms, no antidepressants; depressive symptoms without antidepressant use; antidepressant use without depressive symptoms; and depressive symptoms and antidepressant use.

RESULTS

Long sleep was associated with reduced overall cognitive function (β ± standard error = -0.25 ± 0.07, p < 0.001), with strongest effects in those with depressive symptoms using (-0.74 ± 0.30, p = 0.017) and not using antidepressants (-0.60 ± 0.26, p = 0.024). Weaker but significant effects were observed in those without depressive symptoms (-0.18 ± 0.09, p = 0.044). No significant associations were observed in participants using antidepressants without depressive symptoms.

DISCUSSION

Associations between sleep duration and cognitive performance are strongest in individuals with depressive symptoms, regardless of antidepressant use. Future research should elucidate underlying mechanisms and temporal relationships.

HIGHLIGHTS

Sleeping ≥ 9 hours/night was associated with worse cognitive performance. This association was stronger among those with depression. Long sleepers were more likely to report symptoms of depression. Sleep may be a modifiable risk for cognitive decline in people with depression.

REM sleep and mental disorders on the 70th anniversary of the discovery of REM sleep

The discovery of rapid eye movement sleep in 1953 led to numerous studies investigating the relationship between rapid eye movement sleep abnormalities and psychiatric disorders. The most salient findings were the association of rapid eye movement sleep alterations-reduced rapid eye movement sleep latency, increased rapid eye movement sleep volume of total sleep, and increased rapid eye movement density-with major depression. This paper briefly reviews the history of rapid eye movement sleep research in psychiatry with a focus on the work related to major depressive disorder and some of the various theories that have been proposed to explain the associated rapid eye movement sleep abnormalities. Given the increasing evidence that rapid eye movement sleep is important for emotional processing, memory and cognition, a better understanding of the underlying mechanisms for the relationship between rapid eye movement sleep and mood disorders could lead to improved treatments for these common and disabling illnesses.

Sleep alterations in major depressive disorder and insomnia disorder: A network meta-analysis of polysomnographic studies

Major depressive disorder (MDD) and Insomnia disorder (ID) are characterized by sleep alterations. To define their polysomnographic profiles, we conducted a Network Meta-Analysis comparing MDD and ID patients versus healthy controls (HCs). The literature search, conducted from 2008 up to January 2023 and following PRISMA guidelines, covered PubMed, Web of Science, Scopus, and Embase databases. We addressed publication bias using funnel plot asymmetry inspection and Egger's test, evaluated statistical heterogeneity with I2, and local and global inconsistencies with the separate indirect from direct evidence method and Q between designs, respectively. Pairwise meta-analyses employed a fixed-effects model, while network analysis utilized a random-effect approach. We evaluated 86 ID and 17 MDD studies, comparing sleep parameters for 636 MDDs versus 491 HCs, and 3661 IDs versus 2792 HCs. The network meta-analysis reported that patients with MDD have greater rapid eye movement (REM) sleep duration and REMs density, and lower REM sleep latency compared to IDs. ID patients instead exhibited lower total sleep time and time in bed, and greater wake after sleep onset and non-REM sleep stage 3 than MDD patients. This work emphasized sleep depth and continuity alterations in both MDD and ID, with major involvement of REM sleep in MDD.

Using Wearable Technology to Evaluate Sleep and Stress for Physicians

OBJECTIVES

Physician stress and burnout are increasingly prevalent issues that often are exacerbated by chronic sleep deprivation. Poor sleep not only compromises the well-being of physicians but also can negatively affect patient care and safety. As wearable technology has become more advanced, the potential is growing to use these devices to monitor and analyze physiological metrics such as sleep and stress levels in real time. This systemic review aims to investigate the use of wearable technology to track sleep quality, stress, and burnout among physicians at various levels of training.

METHODS

A systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using Medline, Cochrane, and Embase to identify studies that used wearable technology to monitor sleep and stress outcomes in physicians. Inclusion criteria focused on studies that specifically measured sleep quality, stress, and burnout using wearable technology. Thirteen studies were included in this review. Data extracted from the included studies detailed study design, participant characteristics, type of wearable technology used, and measured sleep outcomes and heart rate variability (HRV) data.

RESULTS

The data of 540 physicians were included in this study, with Emergency Medicine and Trauma Surgery representing the largest proportion of specialties assessed. Physicians not on call slept an average of 398.3 ± 49.0 minutes per night, whereas those on call slept an average of 226.0 ± 71.3 minutes per night. Physicians also spent 82.5 ± 13.4 minutes in rapid eye movement sleep per night and 41.3 ± 21.8 minutes awake in bed before falling asleep. HRV measures showed an average standard deviation of the R-R intervals across studies of 62.7 ± 28.8 milliseconds.

CONCLUSIONS

Wearable technology data indicate that physicians sleep less than the recommended amount per night and have reduced sleep quality measures. HRV data indicate increased levels of stress and burnout. The data provided by wearable technology may improve physician well-being and ultimately patient care.

Sleep Disorders Are Associated with Mental Health, Quality of Life and Stigma in an Italian Cohort of People Living with HIV

Objectives: The aim of this study was to assess sleep quality in people living with HIV (PLWH), and to examine how the sleep sphere interacts with mental health, quality of life and internalized stigma. Methods: A total of 250 PLWH were consecutively enrolled during routine outpatient visits. Each participant completed a 67-item questionnaire. Sleep disturbances were measured using the Pittsburgh Sleep Quality Index (PSQI). The Depression, Anxiety and Stress Scale (DASS-21) was used to measure the mental health status. The Short Form 12 (SF-12) questionnaire was used to measure participants' quality of life. Internalized HIV-related stigma was evaluated using the modified six-item internalized AIDS-related stigma scale. Results: Many of the PLWH were male (69.2%) and the time between HIV diagnosis and first antiretroviral therapy (ART) was over 10 years (69.2% and 64%, respectively). The PSQI component most-cited as problematic by PLWH was habitual sleep efficiency (52.4%). In multivariate analysis models, a higher mean in the PSQI total score was significantly associated with internalized stigma (mean change 1.10), depression (mean change 6. 20), anxiety (mean change 12.15), stress (mean change 6.24), physical (mean change 7.54) and mental (mean change 3.56) quality of life, health status (mean change -6.04), ART adherence (mean change -5.08) and physical activity (mean change -6.20). Conclusions: Our results confirm the role of sleep quality in both mental and physical health and suggest that sleep disorders might also be a significant indicator of psychosocial challenges faced by PLWH.

GPR139, an Ancient Receptor and an Emerging Target for Neuropsychiatric and Behavioral Disorders

GPR139 is an orphan G-protein-coupled receptor that is predominantly expressed in several midbrain regions, e.g., the habenula, striatum, and hypothalamus. GPR139 gene is highly conserved across vertebrate phylogenetic taxa, suggesting its fundamental importance in neurophysiology. Evidence from both animal studies and human genetic association studies has demonstrated that dysregulation of GPR139 expression and function is linked to aberrant behaviors, cognitive deficits, alterations in sleep and alertness, and substance abuse and withdrawal. Animal knockout models suggest that GPR139 plays an anti-opioid role by modulating the signaling activity of the μ-opioid receptor (MOR), as well as the intensity of withdrawal symptoms and nociception in behavioral paradigms. Modulation of GPR139 activity by surrogate agonists such as TAK-041 and JNJ-63533054 has shown promising results in experimental models; however, the use of TAK-041 in clinical trials has produced heterogeneous effects and has not met the intended primary endpoint. Here, we highlight current in vitro and in vivo studies of GPR139, its potential physiological roles, and therapeutic potential in the pathophysiology of neuropsychiatric and behavioral disorders. This review aims to focus on the current knowledge gaps to facilitate future studies that will contribute to the understanding of GPR139 as a therapeutic target for neuropsychiatric and behavioral disorders.

The mediating role of cognitive arousal in the relationship between impulsivity and sleep quality among college students: a random intercept cross-lagged panel analysis

Impulsivity, cognitive arousal, and sleep quality are critical factors affecting college students' well-being and academic performance. While impulsivity negatively influences sleep quality, the mediating role of cognitive arousal remains underexplored. The present study assesses how impulsivity affects sleep quality through cognitive arousal. Specifically, it explores whether impulsive behavior heightens cognitive arousal, leading to impaired sleep quality, and whether these relationships hold over time. A longitudinal design was employed, collecting data from 521 college students across three waves over an academic year. Standardized questionnaires were administered to measure impulsivity, cognitive arousal, and sleep quality at each wave. Structural equation modeling and random-intercept cross-lagged panel models (RI-CLPMs) were utilized to analyze the associations, assessing both the direct effects and the mediating role of cognitive arousal over time. Impulsivity significantly predicted increased cognitive arousal over time, which in turn negatively affected sleep quality. Cognitive arousal was confirmed as a significant mediator in the relationship between impulsivity and sleep quality. These relationships remained consistent across the three-time points, with significant direct effects of impulsivity on cognitive arousal and cognitive arousal on sleep quality. Interventions to reduce cognitive arousal and impulsivity-related behaviors could improve sleep quality among college students. Future research should explore additional environmental and psychological factors influencing these relationships.

Exploring Crocin's Role in Alleviating Memory Impairments and Depression-like Behaviors Induced by REM Sleep Deprivation, Focusing on BDNF and GSK-3β in Male Rats

Rapid-eye movement sleep deprivation (REM SD) drastically alters behavioral functions and the mood state. Evidence demonstrates that the effects of REM SD on cognition and mood vary significantly based on the duration of deprivation. On the other hand, crocin (as a natural therapeutic compound found in Saffron) may be beneficial for the alleviation of SD effect. The present research aimed to explore the effects of REM SD of varying durations on behavioral functions and the expression levels of brain-derived neurotrophic factor (BDNF) and glycogen synthase kinase-3 beta (GSK-3β) in the prefrontal cortex. REM SD was conducted for 1, 5, or 10 days (6 h per day). Crocin was injected intraperitoneally at the dose of 50 mg/kg. The results showed that REM SD for 5- and 10-days increased locomotor activity and rearing, decreased pain threshold, and impaired passive avoidance memory performance. REM SD for 5- and 10-days increased the expression levels of GSK-3β, while only REM SD for 5 days decreased BDNF levels. Crocin (only in rats exposed to REM SD for 5 days) restored behavioral alterations, while in rats exposed to REM SD for 10 days had no effect. Interestingly, crocin in rats exposed to REM SD for 5- and 10-days attenuated GSK-3β upregulation. In addition, crocin in rats exposed to REM SD for 5 but not 10 days attenuated BDNF down regulation. In conclusion, the duration of REM SD is a crucial determinant of its impact on cognitive and mood functions.

Serotonergic psychedelics as potential therapeutics for post-COVID-19 syndrome (or Long COVID): A comprehensive review

RATIONALE

In our ongoing battle against the coronavirus 2019 (COVID-19) pandemic, a major challenge is the enduring symptoms that continue after acute infection. Also known as Long COVID, post-COVID-19 syndrome (PCS) often comes with debilitating symptoms like fatigue, disordered sleep, olfactory dysfunction, and cognitive issues ("brain fog"). Currently, there are no approved treatments for PCS. Recent research has uncovered that the severity of PCS is inversely linked to circulating serotonin levels, highlighting the potential of serotonin-modulating therapeutics for PCS. Therefore, we propose that serotonergic psychedelics, acting mainly via the 5-HT2A serotonin receptor, hold promise for treating PCS.

OBJECTIVES

Our review aims to elucidate potential mechanisms by which serotonergic psychedelics may alleviate the symptoms of PCS.

RESULTS

Potential mechanisms through which serotonergic psychedelics may alleviate PCS symptoms are discussed, with emphasis on their effects on inflammation, neuroplasticity, and gastrointestinal function. Additionally, this review explores the potential of serotonergic psychedelics in mitigating endothelial dysfunction, a pivotal aspect of PCS pathophysiology implicated in organ dysfunction. This review also examines the potential role of serotonergic psychedelics in alleviating specific PCS symptoms, which include olfactory dysfunction, cognitive impairment, sleep disturbances, and mental health challenges.

CONCLUSIONS

Emerging evidence suggests that serotonergic psychedelics may alleviate PCS symptoms. However, further high-quality research is needed to thoroughly assess their safety and efficacy in treating patients with PCS.

The effects of shared, depression-specific, and anxiety-specific internalizing symptoms on negative and neutral episodic memories following post-learning sleep

Emotional memory bias is a common characteristic of internalizing symptomatology and is enhanced during sleep. The current study employs bifactor S-1 modeling to disentangle depression-specific anhedonia, anxiety-specific anxious arousal, and the common internalizing factor, general distress, and test whether these internalizing symptoms interact with sleep to influence memory for emotional and neutral information. Healthy adults (N = 281) encoded scenes featuring either negative objects (e.g., a vicious looking snake) or neutral objects (e.g., a chipmunk) placed on neutral backgrounds (e.g., an outdoor scene). After a 12-hour period of daytime wakefulness (n = 140) or nocturnal sleep (n = 141), participants judged whether objects and backgrounds were the same, similar, or new compared with what they viewed during encoding. Participants also completed the mini version of the Mood and Anxiety Symptom Questionnaire. Higher anxious arousal predicted worse memory across all stimuli features, but only after a day spent being awake-not following a night of sleep. No significant effects were found for general distress and anhedonia in either the sleep or wake condition. In this study, internalizing symptoms were not associated with enhanced emotional memory. Instead, memory performance specifically in individuals with higher anxious arousal was impaired overall, regardless of emotional valence, but this was only the case when the retention interval spanned wakefulness (i.e., not when it spanned sleep). This suggests that sleep may confer a protective effect on general memory impairments associated with anxiety.

What radio waves tell us about sleep!

The ability to assess sleep at home, capture sleep stages, and detect the occurrence of apnea (without on-body sensors) simply by analyzing the radio waves bouncing off people's bodies while they sleep is quite powerful. Such a capability would allow for longitudinal data collection in patients' homes, informing our understanding of sleep and its interaction with various diseases and their therapeutic responses, both in clinical trials and routine care. In this article, we develop an advanced machine-learning algorithm for passively monitoring sleep and nocturnal breathing from radio waves reflected off people while asleep. Validation results in comparison with the gold standard (i.e. polysomnography; n = 880) demonstrate that the model captures the sleep hypnogram (with an accuracy of 80.5% for 30-second epochs categorized into wake, light sleep, deep sleep, or REM), detects sleep apnea (AUROC = 0.89), and measures the patient's Apnea-Hypopnea Index (ICC = 0.90; 95% CI = [0.88, 0.91]). Notably, the model exhibits equitable performance across race, sex, and age. Moreover, the model uncovers informative interactions between sleep stages and a range of diseases including neurological, psychiatric, cardiovascular, and immunological disorders. These findings not only hold promise for clinical practice and interventional trials but also underscore the significance of sleep as a fundamental component in understanding and managing various diseases.

The brain, rapid eye movement sleep, and major depressive disorder: A multimodal neuroimaging study

BACKGROUND

Evidence has established the prominent involvement of rapid eye movement (REM) sleep disturbance in major depressive disorder (MDD). However, the neural correlates of REM sleep in MDD and their clinical significance are less clear.

METHODS

Cross-sectional and longitudinal polysomnography and resting-state functional MRI data were collected from 131 MDD patients and 71 healthy controls to measure REM sleep and voxel-mirrored homotopic connectivity (VMHC). Correlation and mediation analyses were performed to examine the associations between REM sleep, VMHC, and clinical variables. Moreover, we conducted spatial correlations between the neural correlates of REM sleep and a multimodal collection of reference brain maps to facilitate genetic, structural and functional annotations.

RESULTS

MDD patients exhibited REM sleep abnormalities manifesting as higher REM sleep latency and lower REM sleep duration, which were correlated with decreased VMHC of the precentral gyrus and inferior parietal lobe and mediated their associations with more severe anxiety symptoms. Longitudinal data showed that VMHC increase of the inferior parietal lobe was related to improvement of depression symptoms in MDD patients. Spatial correlation analyses revealed that the neural correlates of REM sleep in MDD were linked to gene categories primarily involving cellular metabolic process, signal pathway, and ion channel activity as well as linked to cortical microstructure, metabolism, electrophysiology, and cannabinoid receptor.

CONCLUSION

These findings may add important context to the growing literature on the complex interplay between sleep and MDD, and more broadly may inform future treatment for depression via regulating sleep.

Fractal cycles of sleep, a new aperiodic activity-based definition of sleep cycles

Sleep cycles are defined as episodes of non-rapid eye movement (non-REM) sleep followed by an episode of REM sleep. Fractal or aperiodic neural activity is a well-established marker of arousal and sleep stages measured using electroencephalography. We introduce a new concept of 'fractal cycles' of sleep, defined as a time interval during which time series of fractal activity descend to their local minimum and ascend to the next local maximum. We assess correlations between fractal and classical (i.e. non-REM - REM) sleep cycle durations and study cycles with skipped REM sleep. The sample comprised 205 healthy adults, 21 children and adolescents and 111 patients with depression. We found that fractal and classical cycle durations (89±34 vs 90±25 min) correlated positively (r=0.5, p<0.001). Children and adolescents had shorter fractal cycles than young adults (76±34 vs 94±32 min). The fractal cycle algorithm detected cycles with skipped REM sleep in 91-98% of cases. Medicated patients with depression showed longer fractal cycles compared to their unmedicated state (107±51 vs 92±38 min) and age-matched controls (104±49 vs 88±31 min). In conclusion, fractal cycles are an objective, quantifiable, continuous and biologically plausible way to display sleep neural activity and its cycles.

Temporal ablation of the ciliary protein IFT88 alters normal brainwave patterns

The primary cilium is a hair-like organelle that hosts molecular machinery for various developmental and homeostatic signaling pathways. Its alteration can cause rare ciliopathies such as the Bardet-Biedl and Joubert syndromes, but is also linked to Alzheimer's disease, clinical depression, and autism spectrum disorder. These afflictions are caused by disturbances in a wide variety of genes but a common phenotype amongst them is cognitive impairment. While cilia-mediated neural function has been widely examined in early neurodevelopment, their function in the adult brain is not well understood. To help elucidate the role of cilia in neural activity, we temporally induced the ablation of IFT88, a gene encoding the intraflagellar transport 88 protein which is neccessary for ciliogenesis, in adult mice before performing memory-related behavioral assays and electroencephalogram/electromyogram (EEG/EMG) recordings. Inducible IFT88 KO mice exhibited severe learning deficits in trace fear conditioning and Morris water maze tests. They had strongly affected brainwave activity both under isoflurane induced anesthesia and during normal activity. And additionally, inducible IFT88 KO mice had altered sleep architecture and attenuated phase-amplitude coupling, a process that underlies learning and memory formation. These results highlight the growing significance of primary cilia for healthy neural function in the adult brain.

The application of artificial intelligence in insomnia, anxiety, and depression: A bibliometric analysis

Background

Mental health issues like insomnia, anxiety, and depression have increased significantly. Artificial intelligence (AI) has shown promise in diagnosing and providing personalized treatment.

Objective

This study aims to systematically review the application of AI in addressing insomnia, anxiety, and depression, identifying key research hotspots, and forecasting future trends through bibliometric analysis.

Methods

We analyzed a total of 875 articles from the Web of Science Core Collection (2000-2024) using bibliometric tools such as VOSviewer and CiteSpace. These tools were used to map research trends, highlight international collaboration, and examine the contributions of leading countries, institutions, and authors in the field.

Results

The United States and China lead the field in terms of research output and collaborations. Key research areas include "neural networks," "machine learning," "deep learning," and "human-robot interaction," particularly in relation to personalized treatment approaches. However, challenges around data privacy, ethical concerns, and the interpretability of AI models need to be addressed.

Conclusions

This study highlights the growing role of AI in mental health research and identifies future priorities, such as improving data quality, addressing ethical challenges, and integrating AI more seamlessly into clinical practice. These advancements will be crucial in addressing the global mental health crisis.

REM disruption and REM vagal activity predict extinction recall in trauma-exposed individuals

BACKGROUND

Accumulating evidence suggests that rapid eye movement sleep (REM) supports the consolidation of extinction memory. REM is disrupted in posttraumatic stress disorder (PTSD), and REM abnormalities after traumatic events increase the risk of developing PTSD. Therefore, it was hypothesized that abnormal REM in trauma-exposed individuals may pave the way for PTSD by interfering with the processing of extinction memory. In addition, PTSD patients display reduced vagal activity. Vagal activity contributes to the strengthening of memories, including fear extinction memory, and recent studies show that the role of vagus in memory processing extends to memory consolidation during sleep. Therefore, it is plausible that reduced vagal activity during sleep in trauma-exposed individuals may be an additional mechanism that impairs extinction memory consolidation. However, to date, the contribution of sleep vagal activity to the consolidation of extinction memory or any emotional memory has not been investigated.

METHODS

Trauma-exposed individuals (n = 113) underwent a 2-day fear conditioning and extinction protocol. Conditioning and extinction learning phases were followed by extinction recall 24 h later. The association of extinction recall with REM characteristics and REM vagal activity (indexed as heart rate variability) during the intervening consolidation night was examined.

RESULTS

Consistent with our hypotheses, REM disruption was associated with poorer physiological and explicit extinction memory. Furthermore, higher vagal activity during REM was associated with better explicit extinction memory, and physiological extinction memory in males.

CONCLUSIONS

These findings support the notion that abnormal REM, including reduced REM vagal activity, may contribute to PTSD by impairing the consolidation of extinction memory.

Sleep and Depressive Symptoms in Sedentary Community-Dwelling Older Adults With Sleep Complaints: Findings From Ambulatory Sleep EEG

BACKGROUND

There is limited and inconsistent evidence on the association between electroencephalography (EEG) measured sleep and depressive symptoms among community-dwelling older adults. This study aimed to investigate the cross-sectional association between EEG-measured sleep and depressive symptoms.

METHODS

Using baseline data from a randomized clinical trial, we included 66 sedentary community-dwelling older adults with sleep complaints (≥ 1 self-reported insomnia symptom). Sleep was measured using an in-home sleep EEG (Sleep Profiler™) for 2 nights and the Geriatric Depression Scale (GDS-15) was used to measure depressive symptoms. Multiple linear regression analyses were conducted with each sleep parameter as the primary predictor and GDS score as the outcome, adjusting for age, sex, race, education, marital status, chronic conditions, and Montreal Cognitive Assessment (MoCA) score.

RESULTS

Several sleep variables were associated with depressive symptoms (GDS score), including a higher percentage of sleep stage N1 (B = 0.11, 95% confidence interval [CI]: 0.02 - 0.20) and N2 (B = 0.04, 95% CI: 0.00 - 0.08), a lower percentage of N3 sleep (B = -0.04, 95% CI: -0.08 to -0.01), greater wake after sleep onset (B = 0.01, 95% CI: 0.00 - 0.02), and a greater number of awakenings ≥90s/hour (B = 0.87, 95% CI: 0.21-1.53).

CONCLUSIONS

Our study reveals that among sedentary community-dwelling older adults with sleep complaints, more lighter sleep (stage N1, N2), less deep (N3) sleep, and increased awakenings are associated with more depressive symptoms. Sleep interventions aimed at enhancing sleep architecture may also help alleviate depressive symptoms in this population.

Network structure of REM sleep behavior disorder symptoms in iRBD patients

OBJECTIVE

Employing the REM Sleep Behavior Disorder Questionnaire-Hong Kong (RBDQ-HK) to investigate symptoms and their severity in rapid eye movement (REM) sleep behavior disorder (RBD) patients, this study delves into the construct of RBD through the RBDQ-HK and its links to depression and sleep quality.

METHODS

Data from the RBDQ-HK, the Geriatric Depression Scale (GDS), and the Pittsburgh Sleep Quality Index (PSQI) were compiled from individuals with isolated RBD (iRBD) confirmed by polysomnography. We constructed a network analysis of the RBDQ-HK, measured the centrality of each symptom (node), conducted Exploratory Graph Analysis (EGA) to unveil the dimension structure of the questionnaire, and calculated bridge expected influence (BEI) to identifying critical bridge. Multivariate linear regression was also employed to discover relationships between RBDQ-HK dimensions and variables such as PSQI and GDS.

RESULTS

In our cohort of 455 iRBD patients (299 males), the items in the RBDQ-HK were divided into three dimensions: dream, movement, and SRI/violence. The symptoms identified as most central to RBD were 'shouting or yelling in sleep', 'dream-enacting movements', and 'talking during sleep'. The highest (BEI) was 'violent and aggressive dreams', which has the potential to bridge three dimensions within the symptom network. Depression was significantly correlated with the movement and dream dimensions of RBD, and sleep quality was predominantly related to the dream dimension score.

CONCLUSION

Our findings verify that the principal symptoms of the RBDQ-HK align with the established diagnostic criteria and reveal a three-dimensional structure within RBD symptoms. The relationships between the RBD symptoms, depression, and sleep quality need to be identified for the effective management of RBD patients.

Temporal Ablation of the Ciliary Protein IFT88 Alters Normal Brainwave Patterns

The primary cilium is a hair-like organelle that hosts molecular machinery for various developmental and homeostatic signaling pathways. Its alteration can cause rare ciliopathies such as the Bardet-Biedl and Joubert syndromes, but is also linked to Alzheimer's disease, clinical depression, and autism spectrum disorder. These afflictions are caused by disturbances in a wide variety of genes but a common phenotype amongst them is cognitive impairment. While cilia-mediated neural function has been widely examined in early neurodevelopment, their function in the adult brain is not well understood. To help elucidate the role of cilia in neural activity, we temporally induced the ablation of IFT88, a gene encoding the intraflagellar transport 88 protein which is neccessary for ciliogenesis, in adult mice before performing memory-related behavioral assays and electroencephalogram/electromyogram (EEG/EMG) recordings. Inducible IFT88 KO mice exhibited severe learning deficits in trace fear conditioning and Morris water maze tests. They had strongly affected brainwave activity both under isoflurane induced anesthesia and during normal activity. And additionally, inducible IFT88 KO mice had altered sleep architecture and attenuated phase-amplitude coupling, a process that underlies learning and memory formation. These results highlight the growing significance of primary cilia for healthy neural function in the adult brain.

Using the Complex Network Model to Associate Nutritional, Psychological, and Physical Parameters and Aspects of Sleep with Depression Symptoms

Background/Objectives: Major depressive disorder is a significant public health concern linked to factors such as a low-quality diet, a sedentary lifestyle, and poor sleep quality, all of which contribute to its development; nevertheless, the existing literature lacks a comprehensive framework to effectively integrate these interrelated influences. Methods: To address this gap, we conducted a questionnaire-based study involving 411 individuals aged 18 to 74 and employed a weighted complex network model to clarify the associations among nutritional factors, physical activity levels, psychological parameters, and sleep profiles and depression. In addition to constructing networks that encompass distinct subgroups based on general context, sex differences (female vs. male), and four age categories, our network was designed with a clearly defined target: the score from the Beck Depression Inventory. Results: In all networks studied, psychological parameters (e.g., tension, depression, hostility, fatigue, confusion, and total mood disturbance) emerged as the most influential nodes in relation to the targeted node (Eigenvector centrality of approximately 0.30). Additionally, sleep quality was identified as the next most relevant parameter for the general network (Eigenvector = 0.25), while nutritional factors-particularly carbohydrates-demonstrated greater prestige within the male network (Eigenvector = 0.06). Nutritional parameters had a stronger influence on depressive symptoms among individuals aged 29-39 years (Eigenvectors = 0.09, 0.09, and 0.14 for energy, carbohydrates, and fat, respectively). Conclusions: This novel approach allowed for a clearer visualization of how the studied parameters impact depressive symptoms, revealing significant differences when certain aspects are examined independently across distinct groups.

Classics in Chemical Neuroscience: Deliriant Antihistaminic Drugs

Antihistaminic drugs are widely used clinically and have long been primarily known for their use to treat severe allergic conditions caused by histamine release. Antihistaminic drugs also exert central nervous system (CNS) effects, acting as anxiolytics, hypnotics, and neuroleptics. However, these drugs also have multiple serious neuropharmacological side-effects, inducing delirium, hyperarousal, disorganized behavior, and hallucinations. Due to their robust CNS effects, antihistamines are also increasingly abused, with occasional overdoses and life-threatening toxicity. Here, we discuss chemical and neuropharmacological aspects of antihistaminic drugs in both human and animal (experimental) models and outline their current societal and mental health importance as neuroactive substances.

The effect of weighted blankets on sleep quality and mental health symptoms in people with psychiatric disorders in inpatient and outpatient settings: A systematic review and meta-analysis

There is limited synthesized evidence for weighted blankets usage in psychiatric patients. We performed a PRISMA compliant systematic review and meta-analysis of the effects of weighted blankets on sleep and mental health outcomes in psychiatric patients. MEDLINE, EMBASE, Cochrane Library, and PsycINFO were searched up to December 15th, 2023. Randomized controlled trials (RCT) or cohort studies reporting objective outcome scales of sleep and mental health were included. Standardized mean difference (SMD) measured effect size. Q and I2 tests measured heterogeneity. Cochrane Risk of Bias Tool 2 and NIH Quality Assessment Tool assessed risk of bias. Nine studies of 553 psychiatric inpatients and outpatients with diagnoses including depression, bipolar disorder, ADHD, and autism. 289 participants received weighted blankets and 264 were in control groups. Intervention length ranged from 5 min to one year. Four studies reported evidence for weighted blankets in improving insomnia, total sleep time, and sleep onset latency. Six studies reported evidence for reducing anxiety symptoms. When compared to placebo, those using weighted blankets had improvements to anxiety symptoms (SMD = -0.47, 95% CI: -0.68 to -0.25, p < 0.001). One RCT had low risk of bias, 3 had some concerns, 1 was high risk. Three cohort studies were "fair" and one was "poor" in quality. It was found that weighted blankets can be effective in reducing anxiety in psychiatric patients. However, the literature is limited by heterogeneity of outcome reporting, lack of well designed RCTs, and small sample sizes. Highlighting the need for higher quality studies.

Anxiolytic-like effects of acute serotonin-releasing agents in zebrafish models of anxiety: experimental study and systematic review

Though commonly used to model affective disorders, zebrafish display notable differences in terms of the structure and function of the brain serotonin system, including responses to pharmacological interventions, as compared to mammals. For example, elevation of brain serotonin following acute administration of serotonin reuptake inhibitors (SRIs) generally has anxiogenic effects, both in the clinical situation and in rodent models of anxiety, but previous research has indicated the opposite in zebrafish. However, several issues remain unresolved. We conducted a systematic review of SRI effects in zebrafish models of anxiety and, on the basis of these results, performed a series of experiments further investigating the influence of serotonin-releasing agents on anxiety-like behaviour in zebrafish, with sex-segregated wild-type animals being administered either escitalopram, or the serotonin releaser fenfluramine, in the light-dark test. In the systematic review, we find that the available literature indicates an anxiolytic-like effect of SRIs in the novel-tank diving test. Regarding the light-dark test, most studies reported no behavioural effects of SRIs, although the few that did generally saw anxiolytic-like responses. In the experimental studies, consistent anxiolytic-like effects were observed with neither sex nor habituation influencing treatment response. We find that the general effect of acute SRI administration in zebrafish indeed appears to be anxiolytic-like, indicating, at least partly, differences in the functioning of the serotonin system as compared to mammals and that caution is advised when using zebrafish to model affective disorders.

Psychometric evaluation of the Chinese version of the hospital-acquired insomnia scale (HAIS) and analysis of influencing factors

BACKGROUND

Adequate sleep and rest are essential for patient recovery; however, lack of sleep has become a common problem faced by Chinese patients during hospital stays. Reduced sleep is often associated with a higher risk of disease progression and is strongly associated with increased hospital stay. However, there is no specific tool in China to assess short-term insomnia caused by hospitalization. This study aimed to translate the Hospital-acquired Insomnia Scale (HAIS) into Chinese, test its applicability to Chinese inpatients through reliability and validity indicators, and investigate the potential influencing factors of hospital-acquired insomnia.

METHODS

Psychometric analysis from a sample of 679 hospitalized patients to whom the HAIS questionnaire was applied. The structural validity was assessed by exploratory factor analysis (EFA) and confirmatory factor analysis (CFA), and the content validity of the scale was assessed using the content validity index. Cronbach's alpha coefficient, split-half reliability and test-retest reliability were calculated to evaluate the internal consistency of the scale. Multiple stepwise linear regression analysis was conducted to determine the potential correlates of hospital-acquired insomnia.

RESULTS

EFA supported a four-factor structure with factor loadings for all dimensions greater than 0.40. CFA showed good indicators of model fit. The content validity index of the scale was 0.94. the Cronbach's alpha of the scale was 0.915, the split-half reliability coefficient was 0.819, and the retest reliability was 0.844. Gender, age, total hours of sleep during the night, medical insurance, length of hospital stay, perceived stress level, and perceptions about sleep explained 46.2% of the variance in hospital-acquired insomnia.

CONCLUSION

The Chinese version of HAIS has good psychometric characteristics and is an effective instrument for evaluating hospital-acquired insomnia. In addition, hospital-acquired insomnia is more common in women, of younger age, less than 5 h of sleep a night, without medical insurance, stressed, and patients with more misconceptions about sleep.

Assessment of sleep characteristics using Fitbit Charge 4 in head and neck cancer patients undergoing palliative chemotherapy and radiotherapy: a prospective observational study

Background

Sleep disturbance is prevalent among cancer patients. The quantification of this sleep disturbance is missing, especially in palliative care settings.

Aim

The aim of this study was to study the sleep patterns of the patients undergoing palliative chemotherapy and radiotherapy for head and neck cancer (HNC) using a Fitbit Charge 4 sleep-tracking device.

Design

Prospective observational study.

Setting

A total of 110 HNC patients undergoing palliative chemotherapy and radiotherapy at a tertiary care teaching hospital in Central India.

Results

Forty-four percent of patients had a poor sleep score (less than 60). Average sleep duration was 218.66 ± 139.05 min; non-rapid eye movement (NREM) sleep duration 197.7 ± 115.91 (light NREM 171.36 ± 104 and deep NREM 23.36 ± 16.73); REM sleep duration was 30.44 ± 34.14 min. The Pittsburgh Sleep Quality Index was 10.23 ± 3.45, which indicated sleep deprivation over the past 1 month. Moderate levels of anxiety, depression, confusion, and distress existed in the cohort. Statistically significant but weak correlation existed between sleep score, anxiety, and depression. Strong correlation existed between distress score and sleep score. Confusion score did not have a significant correlation with sleep score.

Conclusion

HNC patients in palliative care settings were chronically sleep deprived. Sleep architecture was also disturbed. Moderate levels of anxiety, depression, confusion, and distress existed in the studied cohort; these psychosocial disturbances had a weak correlation with the sleep score and are likely to be multifactorial.

Trial registration

Institutional Ethics Committee number: IHEC-LOP/2020/IM0349. The study has been registered with clinical trial registry of India with registration number CTRI/2021/03/032400 (http://www.ctri.in).

Sleep quality in eating disorders: A systematic review and meta-analysis

Eating disorders (ED) are psychological disorders characterized by dangerous eating behaviours, including protracted fasting and binge eating. Mental disorders comorbidities (e.g., anxiety and depression), as well as sleep difficulties, are common and might interfere with treatment response. This work investigated sleep quality, circadian preferences, and sleep disorders in ED patients compared to healthy controls (HC) and the impact of ED treatment on patients' sleep. A literature search on Pubmed, Web of Science, Medline, and PsychInfo included 27 studies. Random effect analyses were performed (sample eating disorders = 711; sample healthy controls = 653) and subgroup analyses were calculated based on the ED subgroups: Anorexia Nervosa, Bulimia Nervosa, Binge Eating Disorder. Whole sample analyses showed poorer physiological and subjective sleep quality in patients. Subgroup analyses showed that poorer physiological sleep was present only in anorexia nervosa. Two studies reporting circadian preferences and sleep disorders showed higher evening preference in patients and no differences in apnea prevalence between patients and healthy controls, respectively. Some studies suggested that specialized eating disorder treatments (e.g., Cognitive Behavioural Therapy for ED) can improve sleep quality in patients. Although these findings highlight poorer sleep in patients with ED compared to healthy controls, the mechanisms underlying sleep alterations in eating disorders remain to be identified.

Therapeutic sleep deprivation for major depressive disorder: A randomized controlled trial

BACKGROUND

Major depressive disorder (MDD) is treated primarily using antidepressant drugs, but clinical effects may be delayed for weeks to months. This study investigated the efficacy of brief therapeutic sleep deprivation (TSD) for inducing rapid improvements in MDD symptoms.

METHODS

From November 2020 to February 2023, 54 inpatients with MDD were randomly allocated to TSD and Control groups. The TSD group (23 cases) remained awake for 36 h, while the Control group (31 cases) maintained regular sleep patterns. All participants continued regular drug therapy. Mood was assessed using the 24-item Hamilton Depression Scale (HAMD-24) at baseline and post-intervention in both groups. In the TSD group, the Visual Analogue Scale (VAS) was utilized to evaluate subjective mood during and after the intervention. Cognitive function was assessed at baseline and post-intervention using the Montreal Cognitive Assessment (MoCA). Objective sleep parameters were recorded in the TSD group by polysomnography. The follow-up period spanned one week.

RESULTS

HAMD-24 scores did not differ between groups at baseline or post-intervention. However, the clinical response rate was 34.8 % higher in the TSD group on day 3 post-intervention compared to the Control group (3.2 %), but not sustained by day 7. Moreover, responders demonstrated a faster improvement in the VAS score during TSD than non-responders (p = 0.047). There were no significant differences in MoCA scores or objective sleep parameters between the groups.

LIMITATIONS

Small sample size and notable attrition rate.

CONCLUSIONS

Therapeutic sleep deprivation can rapidly improve MDD symptoms without influencing sleep parameters or cognitive functions. Assessment of longer-term effects and identification of factors predictive of TSD response are warranted.

The dynamic responses of mood and sleep physiology to chronic sleep restriction and subsequent recovery sleep

Healthy sleep of sufficient duration preserves mood and disturbed sleep is a risk factor for a range of psychiatric disorders. As adults commonly experience chronic sleep restriction (SR), an enhanced understanding of the dynamic relationship between sleep and mood is needed, including whether susceptibility to SR-induced mood disturbance differs between sexes. To address these gaps, data from N = 221 healthy adults who completed one of the two multi-day laboratory studies with identical 9-day SR protocols were analyzed. Participants randomized to the SR (n = 205) condition underwent 5 nights of SR to 4 hours of time-in-bed and were then randomized to one of the seven sleep doses that ranged from 0 to 12 hours in 2 hours increments; participants randomized to the control (n = 16) condition received 10 hours time-in-bed on all study nights. The Profile of Mood States (POMS) was used to assess mood every 2 hours during wakefulness and markers of sleep homeostasis (EEG slow-wave activity (SWA)) were derived via polysomnography. Mood progressively deteriorated across SR with marked disturbances in somatic mood components. Altered sleep physiology contributed to mood disturbance whereby increased EEG SWA was associated with increased POMS Total Mood Disturbance scores, a finding specific to males. The mood was restored in a dose-response fashion where improvements were greater with longer sleep doses. These findings suggest that when lifestyle and environmental factors are inhibited in the laboratory, the affective consequences of chronic sleep loss are primarily somatic mood disturbances. Altered sleep homeostasis may contribute to mood disturbance, yet sleep-dependent mechanisms may be sex-specific.

Inflammatory pain in mice induces light cycle-dependent effects on sleep architecture

As a syndrome, chronic pain comprises physical, emotional, and cognitive symptoms such as disability, negative affect, feelings of stress, and fatigue. A rodent model of long-term inflammatory pain, induced by complete Freund's adjuvant (CFA) injection, has previously been shown to cause anhedonia and dysregulated naturalistic behaviors, in a manner similar to animal models of stress. We examined whether this extended to alterations in circadian rhythms and sleep, such as those induced by chronic social defeat stress, using actigraphy and wireless EEG. CFA-induced inflammatory pain profoundly altered sleep architecture in male and female mice. Injection of the hind paw, whether with CFA or saline, reduced some measures of circadian rhythmicity such as variance, period, and amplitude. CFA increased sleep duration primarily in the dark phase, while sleep bout length was decreased in the light and increased in the dark phase. Additionally, CFA reduced wake bout length, especially during the dark phase. Increases in REM and SWS duration and bouts were most significant in the dark phase, regardless of whether CFA had been injected at its onset or 12 hours prior. Taken together, these results indicate that inflammatory pain acutely promotes but also fragments sleep.

Mental health: The REM sleep paradox in depression

The relationship between mental disorders and sleep remains unclear. Two new studies show that the lateral habenula, a brain region associated with value-guided behavior, controls REM sleep and promotes emotional stability but also contributes to REM sleep disinhibition in depression.

A REM-active basal ganglia circuit that regulates anxiety

Rapid eye movement (REM) sleep has been hypothesized to promote emotional resilience, but any neuronal circuits mediating this have not been identified. We find that in mice, somatostatin (Som) neurons in the entopeduncular nucleus (EPSom)/internal globus pallidus are predominantly active during REM sleep. This unique REM activity is both necessary and sufficient for maintaining normal REM sleep. Inhibiting or exciting EPSom neurons reduced or increased REM sleep duration, respectively. Activation of the sole downstream target of EPSom neurons, Vglut2 cells in the lateral habenula (LHb), increased sleep via the ventral tegmental area (VTA). A simple chemogenetic scheme to periodically inhibit the LHb over 4 days selectively removed a significant amount of cumulative REM sleep. Chronic, but not acute, REM reduction correlated with mice becoming anxious and more sensitive to aversive stimuli. Therefore, we suggest that cumulative REM sleep, in part generated by the EP → LHb → VTA circuit identified here, could contribute to stabilizing reactions to habitual aversive stimuli.

Sleep disturbances and incident risk of major depressive disorder in a population-based cohort

Sleep disturbances are well-known symptoms of major depressive disorder (MDD). However, the prospective risk of MDD in the presence of sleep disturbances in a general population-based cohort is not well known. This study investigated associations between both polysomnography (PSG)-based or subjective sleep features and incident MDD. Participants representative of the general population who had never had MDD completed sleep questionnaires (n = 2000) and/or underwent PSG (n = 717). Over 8 years' follow-up, participants completed psychiatric interviews enabling the diagnosis of MDD. Survival Cox models were used to analyze associations between sleep features and MDD incidence. A higher Epworth Sleepiness Scale and presence of insomnia symptoms were significantly associated with a higher incidence of MDD (hazard ratio [HR] [95 % confidence interval (CI)]: 1.062 [1.022-1.103], p = 0.002 and 1.437 [1.064-1.940], p = 0.018, respectively). Higher density of rapid eye movements in rapid eye movement (REM) sleep was associated with a higher incidence of MDD in men (HR 1.270 [95 % CI 1.064-1.516], p = 0.008). In women, higher delta power spectral density was associated with a lower MDD incidence (HR 0.674 [95 % CI 0.463-0.981], p = 0.039). This study confirmed the associations between subjective and objective sleep features and the incidence of MDD in a large community dwelling cohort.

Dopamine agonists in restless leg syndrome treatment and their effects on sleep parameters: A systematic review and meta-analysis

BACKGROUND

Dopamine agonists (DAs) constitute the standard therapeutic scheme for restless leg syndrome (RLS) because they have been proven to be effective. However, DAs may change sleep parameters, thus having adverse effects on patient condition. This meta-analysis clarified the effects of DAs used in RLS treatment on the sleep architecture.

METHODS

PubMed, Embase, and Cochrane Central databases were searched for randomized control trials (RCT) (up to October 2023) that discussed the effects of DAs on sleep architecture in patients with RLS. A meta-analysis employing a random-effects model was conducted. The patients were divided into subgroups according to individual DAs and treatment duration (1 day or ≥4 weeks).

RESULTS

Thirteen eligible randomized placebo-controlled trials were included in the assessment. The effects of three DAs (i.e., pramipexole, ropinirole, and rotigotine) on rapid eye movement (REM) sleep, slow-wave sleep (SWS), and sleep efficiency (SE) were analyzed. Overall, pramipexole significantly improved SE but decreased the percentage of REM sleep among treated patients. Ropinirole also enhanced SE compared with the placebo group. Rotigotine did not affect SE and REM sleep. Subgroup analysis found that pramipexole used for 1 day and ≥4 weeks significantly diminished the percentage of REM sleep. Ropinirole used for 1 day showed similar REM sleep patterns. Finally, none of the three DAs affected SWS.

CONCLUSIONS

This meta-analysis demonstrated that DAs significantly affect sleep parameters.

The effect of REM-sleep disruption on affective processing: A systematic review of human and animal experimental studies

Evidence on the importance of rapid-eye-movement sleep (REMS) in processing emotions is accumulating. The focus of this systematic review is the outcomes of experimental REMS deprivation (REMSD), which is the most common method in animal models and human studies on REMSD. This review revealed that variations in the applied REMSD methods were substantial. Animal models used longer deprivation protocols compared with studies in humans, which mostly reported acute deprivation effects after one night. Studies on animal models showed that REMSD causes aggressive behavior, increased pain sensitivity, reduced sexual behavior, and compromised consolidation of fear memories. Animal models also revealed that REMSD during critical developmental periods elicits lasting consequences on affective-related behavior. The few human studies revealed increases in pain sensitivity and suggest stronger consolidation of emotional memories after REMSD. As pharmacological interventions (such as selective serotonin reuptake inhibitors [SSRIs]) may suppress REMS for long periods, there is a clear gap in knowledge regarding the effects and mechanisms of chronic REMS suppression in humans.

Homeostatic regulation of rapid eye movement sleep by the preoptic area of the hypothalamus

Rapid eye movement sleep (REMs) is characterized by activated electroencephalogram (EEG) and muscle atonia, accompanied by vivid dreams. REMs is homeostatically regulated, ensuring that any loss of REMs is compensated by a subsequent increase in its amount. However, the neural mechanisms underlying the homeostatic control of REMs are largely unknown. Here, we show that GABAergic neurons in the preoptic area of the hypothalamus projecting to the tuberomammillary nucleus (POAGAD2→TMN neurons) are crucial for the homeostatic regulation of REMs in mice. POAGAD2→TMN neurons are most active during REMs, and inhibiting them specifically decreases REMs. REMs restriction leads to an increased number and amplitude of calcium transients in POAGAD2→TMN neurons, reflecting the accumulation of REMs pressure. Inhibiting POAGAD2→TMN neurons during REMs restriction blocked the subsequent rebound of REMs. Our findings reveal a hypothalamic circuit whose activity mirrors the buildup of homeostatic REMs pressure during restriction and that is required for the ensuing rebound in REMs.

Deciphering the Link: Correlating REM Sleep Patterns with Depressive Symptoms via Consumer Wearable Technology

This study investigates the correlation between REM sleep patterns, as measured by the Apple Watch, and depressive symptoms in an undiagnosed population. Employing the Apple Watch for data collection, REM sleep duration and frequency were monitored over a specified period. Concurrently, participants' depressive symptoms were evaluated using standardized questionnaires. The analysis, primarily using Spearman's correlation, revealed noteworthy findings. A significant correlation was observed between an increased REM sleep proportion and higher depressive symptom scores, with a correlation coefficient of 0.702, suggesting a robust relationship. These results highlight the potential of using wearable technology, such as the Apple Watch, in early detection and intervention for depressive symptoms, suggesting that alterations in REM sleep could serve as preliminary indicators of depressive tendencies. This approach offers a non-invasive and accessible means to monitor and potentially preempt the progression of depressive disorders. This study's implications extend to the broader context of mental health, emphasizing the importance of sleep assessment in routine health evaluations, particularly for individuals exhibiting early signs of depressive symptoms.

Major depressive disorder with hypersomnolence complaint: A comparison study with non-depressed individuals examining objective biomarkers

BACKGROUND

Hypersomnolence is common in major depressive disorder (MDD), associated with more severe episodes, suicide and antidepressant resistance. Nevertheless, few studies used polysomnography (PSG) and multiple sleep latency test (MSLT) to characterize these patients. In this context, we compared patients visiting a sleep center for hypersomnolence complaint with MDD (HSC/MDD+) and without MDD (HSC/MDD-).

METHODS

HSC/MDD+ and HSC/MDD- groups were defined according to DSM-5 criteria and CES-D scale, and had a 30 h-PSG with ad libitum-sleep and PSG followed by MLST.

RESULTS

HSC/MDD+ had an increased self-declared total sleep time (sTST) of about 10 h30 similar to HSC/MDD- (630.8 ± 17.3 min-vs-616.5 ± 18.1 min, respectively, p = 0.39). Nevertheless, their objective TST (oTST) on ad libitum PSG was significantly longer and about 10 h50 (648.6 ± 23.9 min-vs-587.4 ± 19.0 min, respectively, p = 0.038). HSC/MDD+ also significantly better estimated their sleep duration, with a lower difference between their sTST and oTST compared to HSC/MDD- (10.0 ± 1.7 %-vs-17.4 ± 2.1 %, respectively, p = 0.009) and confirmed significantly more frequently the hypersomnia diagnosis -i.e. oTST>10H- (82.6 ± 8.1 %-vs-54.6 ± 10.9 %, respectively, p = 0.046). Using the Kupfer index (KI), we confirmed a reduced REM sleep latency in patients MDD/HSC+ (15.2 ± 10.0 %-vs-2.3 ± 2.3 %, respectively, p = 0.039). Both groups had comparable increased diurnal sleepiness assessed with the Epworth scale (14.1 ± 1.1-vs-14.8 ± 1.1, respectively, p = 0.65). HSC/MDD+ had less MSLT sleep latency <8 min (9.1 ± 5.1 %-vs-27.3 ± 6.8 %, respectively, p = 0.048).

LIMITATIONS

Retrospective cross-sectional study.

CONCLUSIONS

HSC/MDD+ accurately estimated their sleep duration, objectively confirmed hypersomnia and may specifically had a decreased Kupfer index.

Orexin Neurons to Sublaterodorsal Tegmental Nucleus Pathway Prevents Sleep Onset REM Sleep-Like Behavior by Relieving the REM Sleep Pressure

Proper timing of vigilance states serves fundamental brain functions. Although disturbance of sleep onset rapid eye movement (SOREM) sleep is frequently reported after orexin deficiency, their causal relationship still remains elusive. Here, we further study a specific subgroup of orexin neurons with convergent projection to the REM sleep promoting sublaterodorsal tegmental nucleus (OXSLD neurons). Intriguingly, although OXSLD and other projection-labeled orexin neurons exhibit similar activity dynamics during REM sleep, only the activation level of OXSLD neurons exhibits a significant positive correlation with the post-inter-REM sleep interval duration, revealing an essential role for the orexin-sublaterodorsal tegmental nucleus (SLD) neural pathway in relieving REM sleep pressure. Monosynaptic tracing reveals that multiple inputs may help shape this REM sleep-related dynamics of OXSLD neurons. Genetic ablation further shows that the homeostatic architecture of sleep/wakefulness cycles, especially avoidance of SOREM sleep-like transition, is dependent on this activity. A positive correlation between the SOREM sleep occurrence probability and depression states of narcoleptic patients further demonstrates the possible significance of the orexin-SLD pathway on REM sleep homeostasis.

REM disruption and REM Vagal Activity Predict Extinction Recall in Trauma-Exposed Individuals

Accumulating evidence suggests that rapid eye movement sleep (REM) supports the consolidation of extinction memory. REM is disrupted in PTSD, and REM abnormalities after traumatic events increase the risk of developing PTSD. Therefore, it was hypothesized that abnormal REM in trauma-exposed individuals may pave the way for PTSD by interfering with the processing of extinction memory. In addition, PTSD patients display reduced vagal activity. Vagal activity contributes to the strengthening of memories, including fear extinction memory, and recent studies show that the role of vagus in memory processing extends to memory consolidation during sleep. Therefore, it is plausible that reduced vagal activity during sleep in trauma-exposed individuals may be an additional mechanism that impairs extinction memory consolidation. However, to date, the contribution of sleep vagal activity to the consolidation of extinction memory or any emotional memory has not been investigated. To test these hypotheses, we examined the association of extinction memory with REM characteristics and REM vagal activity (indexed as heart rate variability) in a large sample of trauma-exposed individuals (n=113). Consistent with our hypotheses, REM disruption was associated with poorer physiological and explicit extinction memory. Furthermore, higher vagal activity during REM was associated with better explicit extinction memory, and physiological extinction memory in males. These findings support the notion that abnormal REM may contribute to PTSD by impairing the consolidation of extinction memory and indicate the potential utility of interventions that target REM sleep characteristics and REM vagal activity in fear-related disorders.

Polysomnographic features of insomnia occurring in major depressive disorder, generalized anxiety disorder and bipolar mania: Comparison with primary insomnia and association with metabolic indicators

BACKGROUND

Insomnia is very common in psychiatric disorders, but the polysomnographic (PSG) characteristics of insomnia in various psychiatric disorders are still not agreed upon. This study aimed to investigate the characteristics of PSG and its relationship with metabolic indicators in insomnia patients with affective disorders and primary insomnia (PI) patients.

METHODS

A total of 38 patients with PI, 44 major depressive disorder patients with insomnia (DI), 49 generalized anxiety disorder patients with insomnia (GI), and 19 bipolar mania patients with insomnia (BI) were included. PSG was used to detect sleep problems in subjects, and biochemical indicators were also collected.

RESULTS

The results of this study found that subjects with BI were lower on REM sleep latency (RL), awakenings number (AN), number of microarousals (NM), and apnea-hypopnea index (AHI) than those with DI and GI, and lower on RL and AN than those with PI. Subjects with PI had lower NM and AHI than those with DI and GI. Patients with DI had a higher RL than those with GI. All results passed Bonferroni correction (p < 0.00078). No differences in biochemical indices were found among the four groups of subjects. Also, AHI was found to be positively correlated with free triiodothyronine (FT3) and fasting blood glucose in subjects.

CONCLUSION

This study suggests that various psychiatric disorders may have their characteristics in terms of PSG parameters, which prompted us to focus on the PSG characteristics of these disorders when assessing them, as well as to focus on their biochemical indicators.

Recommended protocols for the Multiple Sleep Latency Test and Maintenance of Wakefulness Test in children: guidance from the American Academy of Sleep Medicine

The American Academy of Sleep Medicine commissioned a task force of clinical experts in pediatric sleep medicine to review published literature on performing the Multiple Sleep Latency Test (MSLT) and Maintenance of Wakefulness Test for diagnosis and management of central disorders of hypersomnolence among children and adolescents. This paper follows a format similar to that of the paper "Recommended protocols for the Multiple Sleep Latency Test and Maintenance of Wakefulness Test in adults: guidance from the American Academy of Sleep Medicine" that was published in 2021. Since there is insufficient evidence to specify a recommended protocol for the Maintenance of Wakefulness Test in children and adolescents, this paper focuses only on the MSLT protocol. This protocol paper provides guidance to health care providers who order, sleep specialists who interpret, and technical staff who administer the MSLT to pediatric patients. Similar to the adult protocol paper, this document provides guidance based on pediatric expert consensus and evidence-based data when available. Topics include patient preparation, evaluation of medication and substance use, sleep needs before testing, scheduling considerations, optimal test conditions for youth, and documentation. Specific changes recommended for pediatric MSLT protocols include (1) provision of a minimum of 7 hours of sleep (with a minimum 8-hour recording time) on polysomnography the night before the MSLT, ideally meeting age-based needs; (2) use of clinical judgment to guide the need for sleep-disordered breathing treatments before polysomnography-MSLT testing; and (3) shared patient-health care provider decision-making regarding modifications in the protocol for children and adolescents with neurodevelopmental/neurological disorders, young age, and/or delayed sleep phase.

CITATION

Maski KP, Amos LB, Carter JC, Koch EE, Kazmi U, Rosen CL. Recommended protocols for the Multiple Sleep Latency Test and Maintenance of Wakefulness Test in children: guidance from the American Academy of Sleep Medicine. J Clin Sleep Med. 2024;20(4):631-641.

Homeostatic regulation of REM sleep by the preoptic area of the hypothalamus

Rapid-eye-movement sleep (REMs) is characterized by activated electroencephalogram (EEG) and muscle atonia, accompanied by vivid dreams. REMs is homeostatically regulated, ensuring that any loss of REMs is compensated by a subsequent increase in its amount. However, the neural mechanisms underlying the homeostatic control of REMs are largely unknown. Here, we show that GABAergic neurons in the preoptic area of the hypothalamus projecting to the tuberomammillary nucleus (POAGAD2→TMN neurons) are crucial for the homeostatic regulation of REMs. POAGAD2→TMN neurons are most active during REMs, and inhibiting them specifically decreases REMs. REMs restriction leads to an increased number and amplitude of calcium transients in POAGAD2→TMN neurons, reflecting the accumulation of REMs pressure. Inhibiting POAGAD2→TMN neurons during REMs restriction blocked the subsequent rebound of REMs. Our findings reveal a hypothalamic circuit whose activity mirrors the buildup of homeostatic REMs pressure during restriction and that is required for the ensuing rebound in REMs.

Learning beyond sensations: How dreams organize neuronal representations

Semantic representations in higher sensory cortices form the basis for robust, yet flexible behavior. These representations are acquired over the course of development in an unsupervised fashion and continuously maintained over an organism's lifespan. Predictive processing theories propose that these representations emerge from predicting or reconstructing sensory inputs. However, brains are known to generate virtual experiences, such as during imagination and dreaming, that go beyond previously experienced inputs. Here, we suggest that virtual experiences may be just as relevant as actual sensory inputs in shaping cortical representations. In particular, we discuss two complementary learning principles that organize representations through the generation of virtual experiences. First, "adversarial dreaming" proposes that creative dreams support a cortical implementation of adversarial learning in which feedback and feedforward pathways engage in a productive game of trying to fool each other. Second, "contrastive dreaming" proposes that the invariance of neuronal representations to irrelevant factors of variation is acquired by trying to map similar virtual experiences together via a contrastive learning process. These principles are compatible with known cortical structure and dynamics and the phenomenology of sleep thus providing promising directions to explain cortical learning beyond the classical predictive processing paradigm.

Shorter total sleep time is associated with lower CD4+/CD8+ T cell ratios in virally suppressed men with HIV

Study Objectives

Although poor sleep quality is associated with lower CD4+ T cell counts among people living with HIV (PLWH), the association between objective sleep metrics and T lymphocyte subset counts is unknown. We evaluated the association between polysomnography (PSG) derived sleep metrics and T lymphocyte subpopulations in a cohort of men living with HIV.

Methods

Virally suppressed men living with HIV participating in the Multicenter AIDS Cohort Study underwent home overnight PSG. We assessed the association of PSG parameters with CD4+ and CD8+ T cell counts and the CD4+/CD8+ T cell ratio.

Results

Overall, 289 men with mean (±SD) age 55.3 ± 11.3 years and mean CD4+ T cell count 730 ± 308 cells/mm3 were evaluated. Total sleep time (TST) was significantly associated with CD8+ but not CD4+ T cell counts. After adjusting for age, race, depressive symptoms, antidepressant use, and non-nucleoside reverse transcriptase inhibitors use, every hour of shorter TST was associated with an additional 33 circulating CD8+ T cells/mm3 (p = 0.05) and a 5.6% (p = 0.0007) decline in CD4+/CD8+ T cell ratio. In adjusted models, every hour of shorter rapid eye movement (REM) sleep was associated with an additional 113 CD8+ T cells/mm3 (p = 0.02) and a 15.1% lower CD4+/CD8+ T cell ratio (p = 0.006). In contrast, measures of sleep efficiency and sleep-disordered breathing were not associated with differences in T lymphocyte subpopulations.

Conclusions

Our findings suggest that shorter TST and REM sleep durations are associated with differences in T lymphocyte subpopulations among men living with HIV. Addressing sleep may reflect a novel opportunity to improve immune function in PLWH.

Neural substrates underlying REM sleep duration in patients with major depressive disorder: A longitudinal study combining multimodal MRI data

INTRODUCTION

Prior studies have discussed rapid eye movement (REM) sleep disturbance as a potential endophenotype of major depressive disorder (MDD). However, the neural substrates underlying the percentage of REM sleep duration (REM%) and its association with disease progression in MDD remain unclear.

METHODS

One hundred and fourteen MDD patients and 74 healthy controls (HCs) underwent resting-state functional and perfusion magnetic resonance imaging (MRI) scans as well as overnight polysomnography examination to assess brain function and REM%, with 48 patients completing follow-up visits. Correlation and mediation analyses were conducted to investigate the associations among baseline REM%, multimodal brain imaging measures, and the improvement of depressive symptoms at follow-up in MDD.

RESULTS

We found voxel-wise correlations between baseline REM% and multimodal brain imaging metrics in many brain regions involved in sensorimotor, visual processing, emotion, and cognition in patients with MDD. Moreover, the baseline REM% was correlated with the improvement of depressive symptoms from acute to remitted status in patients through regulating brain activity in the left inferior temporal gyrus and cerebral blood flow in the bilateral paracentral lobule.

CONCLUSION

Our findings help to identify the neural underpinnings of REM% in depression and highlight REM% as a potential prognostic biomarker to predict disease progression. These may inform future novel interventions of MDD from the perspective of regulating REM sleep.