REM sleep dysregulation in depression: state of the art

[Chronotherapy of affective disorders: principles and clinical aspects]

BACKGROUND

Chronobiological processes play a critical role in the initial manifestation and course of affective disorders. Chronotherapeutic agents aim to improve sleep-wake cycle disturbances and affective symptoms by modulating the chronobiological neuronal circuitry.

OBJECTIVE

To review the different chronotherapeutic procedures, the current evidence situation and recommendations for clinical applications.

METHOD

Narrative review.

RESULTS

Chronotherapeutic interventions for patients with affective disorders can be nonpharmacological, e.g., light therapy, sleep deprivation, sleep phase advance and dark therapy, pharmacological in the form of melatonin and psychological consisting of interpersonal and social rhythm therapy or cognitive behavioral therapy for insomnia modified for patients with bipolar disorder. Nearly all these interventions show promising data regarding their efficacy in acute depressive or manic episodes or as maintenance therapy. For melatonin, there is less evidence for improvement of affective symptoms than for stabilizing the sleep-wake cycle. Some interventions are well-suited for an outpatient setting, e.g., light therapy, dark therapy and psychotherapy, while others, such as triple chronotherapy consisting of sleep deprivation, sleep phase advance and light therapy, are more suited for in-patient treatment.

CONCLUSION

Chronotherapeutic interventions are versatile in their application and can be combined with each other and used concomitantly with classical psychopharmacotherapy. With a benign side effect profile and good evidence for efficacy, they could play an important role in the treatment of affective disorders; however, this potential is used too rarely in the clinical context.

Evening light environments can be designed to consolidate and increase the duration of REM-sleep

Evening exposure to short-wavelength light has disruptive effects on circadian rhythms and sleep. These effects can be mitigated by blocking short-wavelength (blue) frequencies, which has led to the development of evening blue-depleted light environments (BDLEs). We have previously reported that residing 5 days in an evening BDLE, compared with residing in a normal indoor light environment of similar photopic lux, advances circadian rhythms and increases the duration of rapid eye movement (REM) sleep in a randomized cross-over trial with twelve healthy participants. The current study extends these findings by testing whether residing in the evening BDLE affects the consolidation and microstructure of REM sleep in the same sample. Evening BDLE significantly reduces the fragmentation of REM sleep (p = 0.0003), and REM sleep microarousals in (p = 0.0493) without significantly changing REM density or the latency to first REM sleep episode. Moreover, the increased accumulation of REM sleep is not at the expense of NREM stage 3 sleep. BDLE further has a unique effect on REM sleep fragmentation (p = 0.0479) over and above that of circadian rhythms phase-shift, indicating a non-circadian effect of BDLE. If these effects can be replicated in clinical populations, this may have a therapeutic potential in disorders characterized by fragmented REM sleep.

Sleep, insomnia and mental health

While sleep serves important regulatory functions for mental health, sleep disturbances, in particular insomnia, may favour a state of allostatic overload impairing brain neuroplasticity and stress immune pathways, hence contributing to mental disorders. In this framework, the aim of this work was to link current understanding about insomnia mechanisms with current knowledge about mental health dysregulatory mechanisms. The focus of the present work was on mood, anxiety, and psychotic disorders, which represent important challenges in clinical practice. Literature searches were conducted on clinical, neurobiological, and therapeutic implications for insomnia comorbid with these mental disorders. Given the complexity and heterogeneity of the existing literature, we ended up with a narrative review. Insomnia may play an important role as a risk factor, a comorbid condition and transdiagnostic symptom for many mental disorders including mood/anxiety disorders and schizophrenia. Insomnia may also play a role as a marker of disrupted neuroplasticity contributing to dysregulation of different neurobiological mechanisms involved in these different mental conditions. In this framework, insomnia treatment may not only foster normal sleep processes but also the stress system, neuroinflammation and brain plasticity. Insomnia treatment may play an important preventive and neuroprotective role with cognitive behavioural therapy for insomnia being the treatment with important new evidence of efficacy for insomnia, psychopathology, and indices of disrupted neuroplasticity. On the other hand, pharmacological pathways for insomnia treatment in these mental conditions are still not well defined. Therapeutic options acting on melatonergic systems and new therapeutic options acting on orexinergic systems may represents interesting pathways of interventions that may open new windows on insomnia treatment in mental disorders.

Association of Depressive Symptoms with Sleep Disturbance: A Co-twin Control Study

BACKGROUND

Few studies have comprehensively evaluated the association of depression with sleep disturbance using a controlled twin study design.

PURPOSE

To cross-sectionally evaluate the association of depression with both objective and subjective sleep disturbance.

METHODS

We studied 246 members of the Vietnam Era Twin Registry. We measured depressive symptoms using the Beck Depression Inventory-II (BDI) and assessed major depression using structured clinical interviews. Twins underwent one-night polysomnography and 7-day actigraphy to derive measures of objective sleep and completed the Pittsburgh Sleep Quality Index for subjective sleep. Multivariable mixed-effects models were used to examine the association.

RESULTS

Twins were all male, mostly white (97%), with a mean (SD) age of 68 (2). The mean (SD) BDI was 5.9 (6.3), and 49 (20%) met the criteria for major depression. For polysomnography, each 5-unit higher BDI, within-pair, was significantly associated with 19.7 min longer rapid eye movement (REM) sleep latency, and 1.1% shorter REM sleep after multivariable adjustment. BDI was not associated with sleep architecture or sleep-disordered breathing. For actigraphy, a higher BDI, within-pair, was significantly associated with lower sleep efficiency, more fragmentation and higher variability in sleep duration. BDI was associated with almost all dimensions of self-reported sleep disturbance. Results did not differ by zygosity, and remained consistent using major depression instead of BDI and were independent of the presence of comorbid posttraumatic stress disorder and antidepressant use.

CONCLUSIONS

Depression is associated with REM sleep disruption in lab and sleep fragmentation and sleep variability at home, but not with sleep architecture or sleep-disordered breathing.

Prolonged Sleep Latency and Reduced REM Latency Are Associated with Depressive Symptoms in a Japanese Working Population

BACKGROUND

Examining the relationship between sleep and depression may be important for understanding the aetiology of affective disorders. Most studies that use electroencephalography (EEG) to objectively assess sleep have been conducted using polysomnography in the laboratory. Impaired sleep continuity, including prolonged sleep latency and changes in rapid eye movement (REM) sleep, have been reported to be associated with depression in clinical settings. Here, we aimed to use home EEG to analyse the association between sleep and depressive symptoms.

METHODS

We performed a cross-sectional epidemiological study in a large Japanese working population to identify the EEG parameters associated with depressive symptoms based on the results of a questionnaire survey and home EEG measurements using 1-channel (1-Ch) EEG.

RESULTS

The study included 650 Japanese patients (41.2% male, 44.7 ± 11.5 years) who underwent home EEG monitoring along with the Patient Health Questionnaire-9 (PHQ-9) to assess depressive symptoms. Logistic regression analysis revealed that depressive symptoms (PHQ-9 ≥ 10) were associated with sleep latency (odds ratio (OR) 1.02; 95% confidence interval (CI): 1.00-1.04) and REM latency (OR, 0.99; 95% CI: 0.99-1.00).

CONCLUSIONS

Our results suggest that depressive symptoms are associated with prolonged sleep latency and reduced REM latency in a Japanese working population. The 1-Ch EEG may be a useful tool to monitor sleep and screen depression/depressive symptoms in non-clinical settings.

Interactions between Sleep and Emotions in Humans and Animal Models

Recently, increased interest and efforts were observed in describing the possible interaction between sleep and emotions. Human and animal model studies addressed the implication of both sleep patterns and emotional processing in neurophysiology and neuropathology in suggesting a bidirectional interaction intimately modulated by complex mechanisms and factors. In this context, we aimed to discuss recent evidence and possible mechanisms implicated in this interaction, as provided by both human and animal models in studies. In addition, considering the affective component of brain physiological patterns, we aimed to find reasonable evidence in describing the two-way association between comorbid sleep impairments and psychiatric disorders. The main scientific literature databases (PubMed/Medline, Web of Science) were screened with keyword combinations for relevant content taking into consideration only English written papers and the inclusion and exclusion criteria, according to PRISMA guidelines. We found that a strong modulatory interaction between sleep processes and emotional states resides on the activity of several key brain structures, such as the amygdala, prefrontal cortex, hippocampus, and brainstem nuclei. In addition, evidence suggested that physiologically and behaviorally related mechanisms of sleep are intimately interacting with emotional perception and processing which could advise the key role of sleep in the unconscious character of emotional processes. However, further studies are needed to explain and correlate the functional analysis with causative and protective factors of sleep impairments and negative emotional modulation on neurophysiologic processing, mental health, and clinical contexts.

Eye movement patterns correlate with overt emotional behaviours in rapid eye movement sleep

Growing evidence suggests that sleep plays a key role in regulating emotions. Rapid eye movements (REMs) in REM sleep could be associated with dreams emotions, but supporting evidence is indirect. To highlight this association, we studied the REM sleep during video-polysomnography of 20 subjects with REM sleep behaviour disorder (RBD), a model of enacted dreams offering direct access to the emotional content of the sleeper (face expression, speeches, behaviour). Video and the electro-oculography recordings were divided into 3 s time intervals and classified as non-behavioural, or behavioural (neutral, positive or negative emotions), and as containing no eye movements (EMs), slow eye movements (SEMs) or REMs (isolated or bursts). Compared to the absence of EMs, neutral behaviours successively increased in the presence of SEMs (odd ratio, OR = 1.4), then isolated REMs (OR = 2.8) and then REM bursts (OR = 4.6). Positive behaviours increased with SEMs (OR = 2.8) but did not increase further with isolated REMs (OR = 2.8) and REM bursts (OR = 3). Negative behaviours were absent with SEMs, increased with isolated REMs (OR = 2.6) and further with REM bursts (OR = 10.1). These results support an association between REMs and SEMs, and dream emotions.

Association between the CLOCK gene polymorphism and depressive symptom mediated by sleep quality among non-clinical Chinese Han population

BACKGROUND

Depression is a common mental disorder associated with sleep problems and the circadian clock genes may underlie the relationship between the two in clinical samples. However, little is known about whether poor sleep quality is associated with depressive symptom in healthy individuals and whether is mediated by specific single-nucleotide polymorphisms (SNPs).

METHODS

Using a cross-sectional design, 444 university staff members were randomly recruited in Beijing. We used the Pittsburgh Sleep Quality Index (PSQI) to measure sleep quality, the Zung's Self-rating Depression Scale (SDS) to measure depressive symptom, and the Work Stress Scale to measure job stress. The CLOCK gene rs12649507 polymorphism was genotyped in 289 blood samples.

RESULTS

There were positive inter-correlations between job stress, PSQI and SDS (almost ps < 0.05). GG homozygotes of the SNP had higher PSQI and its sleep duration and daytime dysfunction scores than AA homozygotes (all Bonferroni corrected ps0.05). The SNP had no main effect on the SDS and did not interact with job stress to affect SDS, PSQI and its dimensions (all ps > 0.05). Interestingly, after controlling for job stress and covariates, the significant effect size of the SNP on the SDS mediated by the PSQI was 0.68 (95% CI [0.24, 1.35]).

LIMITATIONS

Some limitations included single professional background, cross-sectional study design, small sample size and potential confounding factors, which could be amended by future research.

CONCLUSIONS

Non-clinical Chinese carrying CLOCK gene rs12649507 G-allele may lead to poor sleep quality and further depression symptoms.

Sleep Disturbances and Depression Are Co-morbid Conditions: Insights From Animal Models, Especially Non-human Primate Model

The incidence rates of depression are increasing year by year. As one of the main clinical manifestations of depression, sleep disorder is often the first complication. This complication may increase the severity of depression and lead to poor prognosis in patients. In the past decades, there have been many methods used to evaluate sleep disorders, such as polysomnography and electroencephalogram, actigraphy, and videography. A large number of rodents and non-human primate models have reproduced the symptoms of depression, which also show sleep disorders. The purpose of this review is to examine and discuss the relationship between sleep disorders and depression. To this end, we evaluated the prevalence, clinical features, phenotypic analysis, and pathophysiological brain mechanisms of depression-related sleep disturbances. We also emphasized the current situation, significance, and insights from animal models of depression, which would provide a better understanding for the pathophysiological mechanisms between sleep disturbance and depression.

Multi-Level Processes and Retina-Brain Pathways of Photic Regulation of Mood

Light exerts powerful biological effects on mood regulation. Whereas the source of photic information affecting mood is well established at least via intrinsically photosensitive retinal ganglion cells (ipRGCs) secreting the melanopsin photopigment, the precise circuits that mediate the impact of light on depressive behaviors are not well understood. This review proposes two distinct retina–brain pathways of light effects on mood: (i) a suprachiasmatic nucleus (SCN)-dependent pathway with light effect on mood via the synchronization of biological rhythms, and (ii) a SCN-independent pathway with light effects on mood through modulation of the homeostatic process of sleep, alertness and emotion regulation: (1) light directly inhibits brain areas promoting sleep such as the ventrolateral preoptic nucleus (VLPO), and activates numerous brain areas involved in alertness such as, monoaminergic areas, thalamic regions and hypothalamic regions including orexin areas; (2) moreover, light seems to modulate mood through orexin-, serotonin- and dopamine-dependent pathways; (3) in addition, light activates brain emotional processing areas including the amygdala, the nucleus accumbens, the perihabenular nucleus, the left hippocampus and pathways such as the retina–ventral lateral geniculate nucleus and intergeniculate leaflet–lateral habenula pathway. This work synthetizes new insights into the neural basis required for light influence mood

Sleep disorders and non-sleep circadian disorders predict depression: a systematic review and meta-analysis of longitudinal studies

Patients with depression often suffer from sleep disorders and non-sleep circadian disorders. However, whether they precede and predict subsequent depression is unclear. We conducted a meta-analysis of studies on sleep disorders and non-sleep circadian disorders. We found insomnia, hypersomnia, short and long sleep duration, obstructive sleep apnea, restless legs syndrome and eveningness orientation at baseline all led to subsequent depression. Those with propensity to late meal patterns, heightened levels of cortisol in awakening response and low robustness of rest-activity rhythm at baseline had higher risks for later depression. Among insomnia subtypes, difficulty initiating sleep and difficulty maintaining sleep predicted future depression. Notably, persistent insomnia at baseline contributed to more than two-fold risk of incident depression compared to insomnia. Moreover, insomnia symptom numbers showed dose-dependent relationship with the incident depression. In conclusion, different types of sleep disorders and non-sleep circadian disorders were proven to be risk factors of subsequent depression, and mechanisms underlying the relationship between sleep disorders, non-sleep circadian disorders and subsequent depression should be further elucidated in the future.

The subthalamic corticotropin-releasing hormone neurons mediate adaptive REM-sleep responses to threat

When an animal faces a threatening situation while asleep, rapid arousal is the essential prerequisite for an adequate response. Here, we find that predator stimuli induce immediate arousal from REM sleep compared with NREM sleep. Using in vivo neural activity recording and cell-type-specific manipulations, we identify neurons in the medial subthalamic nucleus (mSTN) expressing corticotropin-releasing hormone (CRH) that mediate arousal and defensive responses to acute predator threats received through multiple sensory modalities across REM sleep and wakefulness. We observe involvement of the same neurons in the normal regulation of REM sleep and the adaptive increase in REM sleep induced by sustained predator stress. Projections to the lateral globus pallidus (LGP) are the effector pathway for the threat-coping responses and REM-sleep expression. Together, our findings suggest adaptive REM-sleep responses could be protective against threats and uncover a critical component of the neural circuitry at their basis.

Clinical Effectiveness of Muscarinic Receptor-Targeted Interventions in Neuropsychiatric Disorders: A Systematic Review

BACKGROUND

For decades, treatment of mood disorders, psychoses, anxiety and dementia have been confounded by limited efficacy and high rates of treatment resistance. Preclinical and clinical evidence have highlighted disruption of cholinergic signalling in several neuropsychiatric conditions and examined intervention strategies including acetylcholinesterase inhibitors and nicotinic receptor-targeted intervention. However, the effectiveness of these approaches is often curtailed by on-target side effects. Post mortem studies implicate muscarinic receptor dysregulation in neuropsychiatric pathophysiology; therefore, we conducted a systematic review and meta-analysis to investigate the therapeutic efficacy and safety of muscarinic receptor-targeted interventions in adults with neuropsychiatric disorders.

METHODS

PubMed, EMBASE, PsycINFO, EBSCO and Web of Science were searched using relevant keywords from database inception to 7 August 2022. Randomised, double-blind, placebo-controlled studies were included if they investigated the effect of muscarinic receptor-targeted intervention in adults with a diagnosis of a neuropsychiatric disorder and were published in English. A narrative synthesis approach was adopted to describe the findings. Wherever three or more studies with a similar intervention were available, effect sizes were calculated, and a meta-analysis was performed. Cochrane risk-of-bias-2 tool was utilised to assess the risk of bias, and sensitivity analyses were performed to identify publication bias. Certainty analysis (high, moderate, low and/or very low) was conducted using GRADE criteria.

RESULTS

Overall, 33 studies met the inclusion criteria and 5 were included in the meta-analysis. Despite a limited pool with several different interventions, we found therapeutic efficacy of xanomeline (M₁/M₄ agonist) in primary psychotic disorders plus behavioural and psychological symptoms of dementia. Scopolamine showed a significant antidepressant effect in a combined cohort of major depressive and bipolar disorders in the short-term outcome measure, but no effect following cessation of treatment. Results from bias assessments suggest "very low" certainty in the antidepressant effect of scopolamine. Critical limitations of the current literature included low power, high heterogeneity in the patient population and a lack of active comparators.

CONCLUSION

While the results are not definitive, findings on muscarinic receptor-targeted interventions in several mental disorders are promising in terms of efficacy and safety, specifically in treating schizophrenia, mood disorders, and behavioural and psychiatric symptoms of Alzheimer's disease. However, orthosteric muscarinic receptor-targeted interventions are associated with a range of peripheral adverse effects that are thought to be mediated via M₂/M₃ receptors. The orthosteric binding site of muscarinic acetylcholine receptors is remarkably conserved, posing a challenge for subtype-selective interventions; nonetheless allosteric ligands with biased signalling pathways are now in development. We conclude that adequately powered prospective studies with subtype-selective interventions are required to determine the clinical effectiveness of muscarinic-receptor targeted interventions for the treatment of neuropsychiatric disorders.

Development of Autonomic Nervous System Assays as Point-of-Care Tests to Supplement Clinical Judgment in Risk Assessment for Suicidal Behavior: A Review

PURPOSE OF REVIEW

A biomarker point-of-care (POC) test that supplements the psychiatric interview and improves detection of patients at risk for suicide would be of value, and assays of autonomic nervous system (ANS) activity would satisfy the logistical requirements for a POC test. We performed a selective review of the available literature of ANS assays related to risk for suicide.

RECENT FINDINGS

We searched PubMed and Web of Science with the strategy: "suicide OR suicidal" AND "electrodermal OR heart rate variability OR pupillometry OR pupillography." The search produced 119 items, 21 of which provided original data regarding ANS methods and suicide. These 21 studies included 6 for electrodermal activity, 14 for heart rate variability, and 1 for the pupillary light reflex. The 21 papers showed associations between ANS assays and suicide risk in a direction suggesting underlying hyperarousal in patients at risk for suicide. ANS assays show promise for future development as POC tests to supplement clinical decision making in estimating risk for suicide.

Sleep markers in psychiatry: do insomnia and disturbed sleep play as markers of disrupted neuroplasticity in mood disorders? A proposed model

INTRODUCTION

Since insomnia and disturbed sleep may affect neuroplasticity, we aimed at reviewing their potential role as markers of disrupted neuroplasticity involved in mood disorders.

METHOD

We performed a systematic review, according to PRIMA, on PubMed, PsycINFO and Embase electronic databases for literature regarding mood disorders, insomnia, sleep loss/deprivation in relation to different pathways involved in the impairment of neuroplasticity in mood disorders such as 1] alterations in neurodevelopment 2] activation of the stress system 3] neuroinflammation 4] neurodegeneration/neuroprogression, 4] deficit in neuroprotection.

RESULTS

Sixty-five articles were analyzed and a narrative/ theoretical review was conducted. Studies showed that insomnia, sleep loss and sleep deprivation might impair brain plasticity of those areas involved in mood regulation throughout different pathways. Insomnia and disrupted sleep may act as neurobiological stressors that by over-activating the stress and inflammatory systems may affect neural plasticity causing neuronal damage. In addition, disturbed sleep may favor a deficit in neuroprotection hence contributing to impaired neuroplasticity.

CONCLUSIONS

Insomnia and disturbed sleep may play a role as markers of alteration in brain plasticity in mood disorders. Assessing and targeting insomnia in the clinical practice may potentially play a neuroprotective role, contributing to "repairing" alterations in neuroplasticity or to the functional recovery of those areas involved in mood and emotion regulation.

Higher prevalence of geriatric depression, catastrophizing pain and sleep disorders in institutionalized elders: a cross-sectional study in Galle District, Sri Lanka

BACKGROUND

Population aging is a significant social problem in the twenty first century. Recent economic and social changes lead increasing number of elders to spend their lives in elderly homes. Institutionalized elders have to face many physical and psychological problems which negatively impact their quality of life. Geriatric depression (GD), catastrophizing pain (CP) and sleep disorders (SD) are some common problems among them.

METHODS

Present study was designed to assess the prevalence of GD, CP and SD and their correlations in institutionalized elders. A descriptive cross-sectional study was conducted in elderly homes (n = 20) in the Galle district of Sri Lanka enrolling 310 subjects. GD, CP and SD were assessed using validated Sinhala versions of Geriatric Depression Scale (GDS), Pain Catastrophizing Scale (PCS) and Pittsburgh Sleep Quality Index (PSQI) respectively. Data were analyzed using SPSS version 25.0 for windows by using descriptive statistics, the Pearson's chi-square test and Pearson's bivariate correlation (p < 0.05).

RESULTS

Among the participants (response rate: 95.7%), 34.8% (n = 108) and 65.2% (n = 202) were males and females respectively. Age range of the subjects was 60-103 years with the mean age of 74.97 years (SD 8.852). Most of the study subjects (n = 234, 75.5%) had spent five or less than 5 years in elderly homes at the time of the study and 52.8% (n = 164) of them were unmarried. GD was present in 76.5% (95% CI: 71.7-81.2) of subjects and of them 44% had moderate to severe depression. PCS revealed that 29% (95% CI: 24.0-34.1) had CP. SD were identified in 55.5% (95% CI: 49.5-61.0) of elders and according to PSQI, 86% (95% CI: 82.3-90.0) had poor quality sleep. Positive correlations between GD and CP (r = 0.24, p < 0.01), GD and SD (r = 0.13, p = 0.02), CP and SD (r = 0.32, p < 0.01) were statistically significant.

CONCLUSIONS

Prevalence of GD, CP and SD were significantly higher in this sample of institutionalized elders who were apparently healthy. Findings highlighted the importance of early screening of physical and psychological problems in institutionalized elders to assure better quality of life and to reduce the burden to health care system of the country.

Increased Serum Prolactin and Excessive Daytime Sleepiness: An Attempt of Proof-of-Concept Study

The objectives of this study were: (1) to identify subjects with hyperprolactinemia in a clinical sample of patients; (2) to compare the neurologic, psychiatric, and sleep conditions found in patients subgrouped by excessive daytime sleepiness (EDS) and hyperprolactinemia; and (3) to identify patients with hyperprolactinemia and EDS not supported by the presence of any other neurologic, psychiatric, or sleep disorder, or substance/medication use. A retrospective chart review of inpatients was carried out in order to identify all patients in whom the prolactin (PRL) serum levels were determined. A total of 130 subjects were retrieved: 55 had increased levels of PRL, while the remaining 75 participants had normal PRL levels. EDS was reported by 32 (58.2%) participants with increased PRL and 34 (45.3%) with normal PRL. Obstructive sleep apnea or other sleep or neurologic/psychiatric conditions could explain EDS in all participants with normal PRL. Among subjects with increased PRL, eight had no other neurologic/psychiatric or sleep disorder (or drug) potentially causing EDS; these participants, at polysomnography, had time in bed, sleep period time, and total sleep time longer than those with EDS associated to another condition. These findings can be considered as a preliminary indication of a role of hyperprolactinemia in EDS and represent a basis for future controlled studies able to test this hypothesis in a reliable, objective, and methodologically more appropriate way.

Increased Serum Prolactin and Excessive Daytime Sleepiness: An Attempt of Proof-of-Concept Study

The objectives of this study were: (1) to identify subjects with hyperprolactinemia in a clinical sample of patients; (2) to compare the neurologic, psychiatric, and sleep conditions found in patients subgrouped by excessive daytime sleepiness (EDS) and hyperprolactinemia; and (3) to identify patients with hyperprolactinemia and EDS not supported by the presence of any other neurologic, psychiatric, or sleep disorder, or substance/medication use. A retrospective chart review of inpatients was carried out in order to identify all patients in whom the prolactin (PRL) serum levels were determined. A total of 130 subjects were retrieved: 55 had increased levels of PRL, while the remaining 75 participants had normal PRL levels. EDS was reported by 32 (58.2%) participants with increased PRL and 34 (45.3%) with normal PRL. Obstructive sleep apnea or other sleep or neurologic/psychiatric conditions could explain EDS in all participants with normal PRL. Among subjects with increased PRL, eight had no other neurologic/psychiatric or sleep disorder (or drug) potentially causing EDS; these participants, at polysomnography, had time in bed, sleep period time, and total sleep time longer than those with EDS associated to another condition. These findings can be considered as a preliminary indication of a role of hyperprolactinemia in EDS and represent a basis for future controlled studies able to test this hypothesis in a reliable, objective, and methodologically more appropriate way.

Evaluation of Automated Hypnogram Analysis on Multi-Scored Polysomnographies

A new method for automated sleep stage scoring of polysomnographies is proposed that uses a random forest approach to model feature interactions and temporal effects. The model mostly relies on features based on the rules from the American Academy of Sleep Medicine, which allows medical experts to gain insights into the model. A common way to evaluate automated approaches to constructing hypnograms is to compare the one produced by the algorithm to an expert's hypnogram. However, given the same data, two expert annotators will construct (slightly) different hypnograms due to differing interpretations of the data or individual mistakes. A thorough evaluation of our method is performed on a multi-labeled dataset in which both the inter-rater variability as well as the prediction uncertainties are taken into account, leading to a new standard for the evaluation of automated sleep stage scoring algorithms. On all epochs, our model achieves an accuracy of 82.7%, which is only slightly lower than the inter-rater disagreement. When only considering the 63.3% of the epochs where both the experts and algorithm are certain, the model achieves an accuracy of 97.8%. Transition periods between sleep stages are identified and studied for the first time. Scoring guidelines for medical experts are provided to complement the certain predictions by scoring only a few epochs manually. This makes the proposed method highly time-efficient while guaranteeing a highly accurate final hypnogram.

Association of accelerometer-derived sleep measures with lifetime psychiatric diagnoses: A cross-sectional study of 89,205 participants from the UK Biobank

BACKGROUND

Sleep problems are both symptoms of and modifiable risk factors for many psychiatric disorders. Wrist-worn accelerometers enable objective measurement of sleep at scale. Here, we aimed to examine the association of accelerometer-derived sleep measures with psychiatric diagnoses and polygenic risk scores in a large community-based cohort.

METHODS AND FINDINGS

In this post hoc cross-sectional analysis of the UK Biobank cohort, 10 interpretable sleep measures-bedtime, wake-up time, sleep duration, wake after sleep onset, sleep efficiency, number of awakenings, duration of longest sleep bout, number of naps, and variability in bedtime and sleep duration-were derived from 7-day accelerometry recordings across 89,205 participants (aged 43 to 79, 56% female, 97% self-reported white) taken between 2013 and 2015. These measures were examined for association with lifetime inpatient diagnoses of major depressive disorder, anxiety disorders, bipolar disorder/mania, and schizophrenia spectrum disorders from any time before the date of accelerometry, as well as polygenic risk scores for major depression, bipolar disorder, and schizophrenia. Covariates consisted of age and season at the time of the accelerometry recording, sex, Townsend deprivation index (an indicator of socioeconomic status), and the top 10 genotype principal components. We found that sleep pattern differences were ubiquitous across diagnoses: each diagnosis was associated with a median of 8.5 of the 10 accelerometer-derived sleep measures, with measures of sleep quality (for instance, sleep efficiency) generally more affected than mere sleep duration. Effect sizes were generally small: for instance, the largest magnitude effect size across the 4 diagnoses was β = -0.11 (95% confidence interval -0.13 to -0.10, p = 3 × 10-56, FDR = 6 × 10-55) for the association between lifetime inpatient major depressive disorder diagnosis and sleep efficiency. Associations largely replicated across ancestries and sexes, and accelerometry-derived measures were concordant with self-reported sleep properties. Limitations include the use of accelerometer-based sleep measurement and the time lag between psychiatric diagnoses and accelerometry.

CONCLUSIONS

In this study, we observed that sleep pattern differences are a transdiagnostic feature of individuals with lifetime mental illness, suggesting that they should be considered regardless of diagnosis. Accelerometry provides a scalable way to objectively measure sleep properties in psychiatric clinical research and practice, even across tens of thousands of individuals.

Polysomnography in seasonal affective disorder: A systematic review and meta-analysis

BACKGROUND

. Although sleep disturbances are ubiquitous in depression, studies assessing sleep architecture lead to conflicting results, possibly because of the heterogeneity in this disorder. We aimed to focus on Seasonal Affective Disorder (SAD), which is directly associated with circadian and sleep homeostasis impairments.

METHODS

. A systematic search was conducted in July 2019. Original papers reporting data about night sleep architecture using polysomnography (PSG), in SAD or remitted-SAD and controls, were included.

RESULTS

. Seven studies were retained and included 183 individuals, including 109 patients with SAD and 74 healthy controls. The random-effects meta-analysis showed that rapid eye movement sleep (REM) was significantly increased in SAD compared to controls (REM amount: SMD=1[0.11,1.88], p = 0.027; REM percentage: SMD=0.71[0.02,1.40], p = 0.045). Remitted SAD patients, compared to controls, also had a significantly increased REM sleep (REM amount: SMD=1.84[0.78,2.90], p<0.001; REM percentage: SMD=1.27[0.51,2.03], p = 0.001) and a significantly decreased REM latency (SMD=-0.93[-1.73,-0.13], p = 0.022). No differences were observed for total sleep time, sleep efficiency, and slow-wave-sleep.

LIMITATIONS

. Most studies had small sample size, with no placebo group and with open designs.

CONCLUSIONS

. REM sleep amount and latency appear altered both during the acute and remitted phase of SAD, representing trait markers with interesting diagnosis and therapeutic implications.

Impact of Insomnia Symptoms on the Clinical Presentation of Depressive Symptoms: A Cross-Sectional Population Study

Objective: Insomnia and depression are prevalent disorders that often co-occur. This study aimed to investigate the impact of clinically significant insomnia symptoms on the prevalence and clinical presentation of clinically significant depressive symptoms and vice versa. Methods: This study used data from the Korean Headache-Sleep Study (KHSS), a nationwide cross-sectional population-based survey regarding headache and sleep. Clinically significant insomnia symptoms were defined as Insomnia Severity Index (ISI) scores ≥ 10 and clinically significant depressive symptoms were defined as Patient Health Questionnaire-9 (PHQ-9) scores ≥ 10, respectively. We referred clinically significant insomnia symptoms and clinically significant depressive symptoms as insomnia symptoms and depressive symptoms, respectively. Results: Of 2,695 participants, 290 (10.8%) and 116 (4.3%) were classified as having insomnia and depressive symptoms, respectively. The prevalence of depressive symptoms was higher among participants with insomnia symptoms than in those without insomnia symptoms (25.9 vs. 1.7%, respectively, P < 0.001). Among participants with depressive symptoms, the PHQ-9 scores were not significantly different between participants with and without insomnia symptoms (P = 0.124). The prevalence of insomnia symptoms was significantly higher among participants with depressive symptoms than in those without depressive symptoms (64.7 vs. 8.3%, respectively, P < 0.001). The ISI scores were significantly higher among participants with insomnia and depressive symptoms than in participants with insomnia symptoms alone (P < 0.001). Conclusions: Participants with depressive symptoms had a higher risk of insomnia symptoms than did those without depressive symptoms. The severity of depressive symptoms did not significantly differ based on insomnia symptoms among participants with depressive symptoms; however, the severity of insomnia symptoms was significantly higher in participants with depressive symptoms than in those without depressive symptoms.

Chronic antidepressant treatment rescues abnormally reduced REM sleep theta power in socially defeated rats

The effects of chronic antidepressant (AD) treatment on sleep disturbances in rodent chronic stress models have not been thoroughly investigated. Here, we show that chronic social defeat stress (SDS) in rats induces prolonged social avoidance, alterations in sleep architecture (increased total rapid eye movement [REM] sleep duration, bout, and shortened REM latency), and contextual but not cued fear memory deficits, even 1 month after the last SDS. These abnormalities were associated with changes in electroencephalography (EEG) spectral powers, including reduced REM sleep theta power during the light phase. Chronic treatment with two different classes of antidepressants (ADs), imipramine and fluoxetine, significantly ameliorated these behavioral, sleep, and EEG abnormalities. Interestingly, REM theta power was normalized by chronic (1 month) but not 1 week AD administration and solely correlated with the ratio (an objective indicator) of social interaction 1 month after the last SDS. These data suggest that reductions in REM sleep theta power, an EEG parameter that has never been directly investigated in humans, is a core sleep symptom in socially defeated rats, and, potentially, also in patients with stress-related psychiatric disorders, including major depressive and posttraumatic stress disorders.

[Arousal and regulatory systems in the system of research domain criteria]

BACKGROUND

The RDoC (research domain criteria) domain arousal and regulatory systems plays an important role for psychiatric disorders.

OBJECTIVE

What is the association between physiology and function of arousal, sleep and circadian rhythms and psychiatric disorders? What are the therapeutic consequences?

MATERIAL AND METHOD

In this narrative review the most important findings related to the topic are presented briefly and concisely. First, the physiology and function of the systems are described. Then the association with various psychiatric disorders is elucidated and therapeutic approaches are discussed.

RESULTS

The treatment of disorders of the arousal system plays a role in a broad group of psychiatric disorders. It is especially important to incorporate the disturbance of the arousal system into therapeutic concepts of affective disorders, schizophrenia, attention deficit hyperactivity disorder (ADHD) and substance abuse.

CONCLUSION

The dimensional concept of RDoC is reflected in DSM‑5 in the simultaneous registration of sleep disturbances and psychiatric disorders, which has important therapeutic consequences. The relationship between sleep function and the development of psychiatric disorders needs continued intensive research.

Sex differences in sleep and influence of the menstrual cycle on women's sleep in junior endurance athletes

Previous research shows that female athletes sleep better according to objective parameters but report worse subjective sleep quality than male athletes. However, existing sleep studies did not investigate variations in sleep and sleep stages over longer periods and have, so far, not elucidated the role of the menstrual cycle in female athletes' sleep. To address these methodological shortcomings, we investigated sex differences in sleep and sleep stages over 61 continuous days in 37 men and 19 women and examined the role of the menstrual cycle and its phases in 15 women. Sleep was measured by a non-contact radar, and menstrual bleeding was self-reported. Associations were investigated with multilevel modeling. Overall, women tended to report poorer subjective sleep quality (p = .057), but objective measurements showed that women obtained longer sleep duration (p < .001), more light (p = .013) and rapid eye movement sleep (REM; hours (h): p < .001, %: p = .007), shorter REM latency (p < .001), and higher sleep efficiency (p = .003) than men. R2 values showed that sleep duration, REM and REM latency were especially affected by sex. Among women, we found longer time in bed (p = .027) and deep sleep (h: p = .036), and shorter light sleep (%: p = .021) during menstrual bleeding vs. non-bleeding days; less light sleep (h: p = .040), deep sleep (%: p = .013) and shorter REM latency (p = .011) during the menstrual than pre-menstrual phase; and lower sleep efficiency (p = .042) and more deep sleep (%: p = .026) during the follicular than luteal phase. These findings indicate that the menstrual cycle may impact the need for physiological recovery, as evidenced by the sleep stage variations. Altogether, the observed sex differences in subjective and objective sleep parameters may be related to the female athletes' menstrual cycle. The paper provides unique data of sex differences in sleep stages and novel insights into the role of the menstrual cycle in sleep among female athletes.

Nucleus Accumbens Medium Spiny Neuron Subtypes Differentially Regulate Stress-Associated Alterations in Sleep Architecture

BACKGROUND

Stress is implicated in the pathophysiology of major depression and posttraumatic stress disorder. These conditions share core features, including motivational deficits, heighted anxiety, and sleep dysregulation. Chronic stress produces these same features in rodents, with some individuals being susceptible or resilient, as seen in humans. While stress-induced neuroadaptations within the nucleus accumbens are implicated in susceptibility-related dysregulation of motivational and emotional behaviors, their effects on sleep are unclear.

METHODS

We used chemogenetics (DREADDs [designer receptors exclusively activated by designer drugs]) to examine the effects of selective alterations in activity of nucleus accumbens medium spiny neurons expressing dopamine D₁ receptors (D1-MSNs) or dopamine D₂ receptors (D2-MSNs) on sleep-related end points. Mice were implanted with wireless transmitters enabling continuous collection of data to quantify vigilance states over a 20-day test period. Parallel cohorts were examined in behavioral tests assessing stress susceptibility.

RESULTS

D1- and D2-MSNs play dissociable roles in sleep regulation. Stimulation of inhibitory or excitatory DREADDs expressed in D1-MSNs exclusively affects rapid eye movement sleep, whereas targeting D2-MSNs affects slow wave sleep. The combined effects of D1-MSN inhibition and D2-MSN activation on sleep resemble those of chronic social defeat stress. Alterations in D1-MSN function also affect stress susceptibility in social behavior tests. Elevation of CREB (cAMP response element-binding protein) within D1-MSNs is sufficient to produce stress-like effects on rapid eye movement sleep.

CONCLUSIONS

In addition to regulation of motivational and emotional behaviors, the nucleus accumbens also influences sleep, an end point with high translational relevance. These findings provide a neural basis for comorbidity in key features of stress-related illness.

The effect of sleep deprivation and restriction on mood, emotion, and emotion regulation: three meta-analyses in one

STUDY OBJECTIVES

New theory and measurement approaches have facilitated nuanced investigation of how sleep loss impacts dimensions of affective functioning. To provide a quantitative summary of this literature, three conceptually related meta-analyses examined the effect of sleep restriction and sleep deprivation on mood, emotion, and emotion regulation across the lifespan (i.e. from early childhood to late adulthood).

METHODS

A total of 241 effect sizes from 64 studies were selected for inclusion, and multilevel meta-analytic techniques were used when applicable.

RESULTS

There was a moderate, positive effect of sleep loss on negative mood (g = 0.45), which was stronger for studies with younger samples, as well as a large, negative effect of sleep loss on positive mood (g = -0.94). For negative mood only, studies that used total sleep deprivation had larger effect sizes than studies that restricted sleep. After correcting for publication bias, a modest but significant negative effect for sleep loss on emotion (g = -0.11) was found; the valence of emotional stimuli did not change the direction of this effect, and type of sleep manipulation was also not a significant moderator. Finally, sleep restriction had a small, negative effect on adaptive emotion regulation (g = -0.32), but no significant impact on maladaptive emotion regulation (g = 0.14); all studies on adaptive emotion regulation were conducted with youth samples.

CONCLUSIONS

Sleep loss compromises optimal affective functioning, though the magnitude of effects varies across components. Findings underscore the importance of sleep for healthy affective outcomes.

Age-Related Cognitive and Motor Decline in a Mouse Model of CDKL5 Deficiency Disorder is Associated with Increased Neuronal Senescence and Death

CDKL5 deficiency disorder (CDD) is a severe neurodevelopmental disease caused by mutations in the X-linked CDKL5 gene. Children affected by CDD display a clinical phenotype characterized by early-onset epilepsy, intellectual disability, motor impairment, and autistic-like features. Although the clinical aspects associated with CDKL5 mutations are well described in children, adults with CDD are still under-characterized. Similarly, most animal research has been carried out on young adult Cdkl5 knockout (KO) mice only. Since age represents a risk factor for the worsening of symptoms in many neurodevelopmental disorders, understanding age differences in the development of behavioral deficits is crucial in order to optimize the impact of therapeutic interventions. Here, we compared young adult Cdkl5 KO mice with middle-aged Cdkl5 KO mice, at a behavioral, neuroanatomical, and molecular level. We found an age-dependent decline in motor, cognitive, and social behaviors in Cdkl5 KO mice, as well as in breathing and sleep patterns. The behavioral decline in older Cdkl5 KO mice was not associated with a worsening of neuroanatomical alterations, such as decreased dendritic arborization or spine density, but was paralleled by decreased neuronal survival in different brain regions such as the hippocampus, cortex, and basal ganglia. Interestingly, we found increased β-galactosidase activity and DNA repair protein levels, γH2AX and XRCC5, in the brains of older Cdkl5 KO mice, which suggests that an absence of Cdkl5 accelerates neuronal senescence/death by triggering irreparable DNA damage. In summary, this work provides evidence that CDKL5 may play a fundamental role in neuronal survival during brain aging and suggests a possible worsening with age of the clinical picture in CDD patients.

The influence of antidepressants and actigraphy-derived sleep characteristics on pediatric multiple sleep latency testing

STUDY OBJECTIVES

Research evaluating the influence of rapid eye movement suppressing antidepressants (REMS-AD) on multiple sleep latency test (MSLT) results and the value of performing actigraphy prior to this test in children and adolescents is lacking. We examined the impact of REMS-AD and actigraphy parameters on mean sleep latency (MSL) and sleep-onset REM episodes (SOREMs) on MSLT in a pediatric clinical sample.

METHODS

This was a retrospective chart review at a quarternary referral center. We identified 164 MSLTs conducted in patients aged less than 18 years between 2014-2017. Correlations between REMS-AD, self-reported sleep duration, actigraphy parameters and each of the outcomes (MSL and SOREMs) were examined. Regression analyses accounting for clinical characteristics were performed.

RESULTS

Mean age of the sample was 11.9±4.19 years, 62% were female, 28 (17%) were on REMS-AD (48% of whom were able to discontinue these medications prior to MSLT) and mean pediatric daytime sleepiness score was 21.7±6.1. MSL was 11.27±5.77 min and mean number of SOREMs 0.55±1.04. Patients on a REMS-AD at initial assessment had fewer SOREMs compared to those not taking these medications (0.17±0.19 versus 0.62±0.09; p=0.04); no difference was noted in MSL (10.36±1.10 versus 11.47±0.50; p=0.36). Increased time in bed on actigraphy (TIBa) correlated with a longer MSL and fewer SOREMs (r=0.23; p=0.04 and r=0.316; p=0.004 respectively). Following regression analyses, use of REMS-AD continued to remain associated with fewer SOREMs; greater TIBa, but not self-reported sleep duration, was associated with a longer MSL (all p<0.05).

CONCLUSIONS

Clinicians should account for the use of REMS-AD and utilize actigraphy to determine time in bed while interpreting the results of a pediatric MSLT.

Sleep and Memory Consolidation Dysfunction in Psychiatric Disorders: Evidence for the Involvement of Extracellular Matrix Molecules

Sleep disturbances and memory dysfunction are key characteristics across psychiatric disorders. Recent advances have revealed insight into the role of sleep in memory consolidation, pointing to key overlap between memory consolidation processes and structural and molecular abnormalities in psychiatric disorders. Ongoing research regarding the molecular mechanisms involved in memory consolidation has the potential to identify therapeutic targets for memory dysfunction in psychiatric disorders and aging. Recent evidence from our group and others points to extracellular matrix molecules, including chondroitin sulfate proteoglycans and their endogenous proteases, as molecules that may underlie synaptic dysfunction in psychiatric disorders and memory consolidation during sleep. These molecules may provide a therapeutic targets for decreasing strength of reward memories in addiction and traumatic memories in PTSD, as well as restoring deficits in memory consolidation in schizophrenia and aging. We review the evidence for sleep and memory consolidation dysfunction in psychiatric disorders and aging in the context of current evidence pointing to the involvement of extracellular matrix molecules in these processes.

EEG and Sleep Effects of Tramadol Suggest Potential Antidepressant Effects with Different Mechanisms of Action

Tramadol is a widely used, centrally acting, opioid analgesic compound, with additional inhibitory effects on the synaptic reuptake of serotonin and noradrenaline, as well as on the 5-HT₂ and NMDA receptors. Preclinical and clinical evidence also suggests its therapeutic potential in the treatment of depression and anxiety. The effects of most widely used antidepressants on sleep and quantitative electroencephalogram (qEEG) are well characterized; however, such studies of tramadol are scarce. Our aim was to characterize the effects of tramadol on sleep architecture and qEEG in different sleep–wake stages. EEG-equipped Wistar rats were treated with tramadol (0, 5, 15 and 45 mg/kg) at the beginning of the passive phase, and EEG, electromyogram and motor activity were recorded. Tramadol dose-dependently reduced the time spent in rapid eye movement (REM) sleep and increased the REM onset latency. Lower doses of tramadol had wake-promoting effects in the first hours, while 45 mg/kg of tramadol promoted sleep first, but induced wakefulness thereafter. During non-REM sleep, tramadol (15 and 45 mg/kg) increased delta and decreased alpha power, while all doses increased gamma power. In conclusion, the sleep-related and qEEG effects of tramadol suggest antidepressant-like properties, including specific beneficial effects in selected patient groups, and raise the possibility of a faster acting antidepressant action.

Selective activation of serotoninergic dorsal raphe neurons facilitates sleep through anxiolysis

A role for the brain's serotoninergic (5HT) system in the regulation of sleep and wakefulness has been long suggested. Yet, previous studies employing pharmacological, lesion and genetically driven approaches have produced inconsistent findings, leaving 5HT's role in sleep-wake regulation incompletely understood. Here we sought to define the specific contribution of 5HT neurons within the dorsal raphe nucleus (DRN5HT) to sleep and arousal control. To do this, we employed a chemogenetic strategy to selectively and acutely activate DRN5HT neurons and monitored sleep-wake using electroencephalogram recordings. We additionally assessed indices of anxiety using the open field and elevated plus maze behavioral tests and employed telemetric-based recordings to test effects of acute DRN5HT activation on body temperature and locomotor activity. Our findings indicate that the DRN5HT cell population may not modulate sleep-wake per se, but rather that its activation has apparent anxiolytic properties, suggesting the more nuanced view that DRN5HT neurons are sleep permissive under circumstances that produce anxiety or stress.

Relationship Between Major Depression Symptom Severity and Sleep Collected Using a Wristband Wearable Device: Multicenter Longitudinal Observational Study

BACKGROUND

Sleep problems tend to vary according to the course of the disorder in individuals with mental health problems. Research in mental health has associated sleep pathologies with depression. However, the gold standard for sleep assessment, polysomnography (PSG), is not suitable for long-term, continuous monitoring of daily sleep, and methods such as sleep diaries rely on subjective recall, which is qualitative and inaccurate. Wearable devices, on the other hand, provide a low-cost and convenient means to monitor sleep in home settings.

OBJECTIVE

The main aim of this study was to devise and extract sleep features from data collected using a wearable device and analyze their associations with depressive symptom severity and sleep quality as measured by the self-assessed Patient Health Questionnaire 8-item (PHQ-8).

METHODS

Daily sleep data were collected passively by Fitbit wristband devices, and depressive symptom severity was self-reported every 2 weeks by the PHQ-8. The data used in this paper included 2812 PHQ-8 records from 368 participants recruited from 3 study sites in the Netherlands, Spain, and the United Kingdom. We extracted 18 sleep features from Fitbit data that describe participant sleep in the following 5 aspects: sleep architecture, sleep stability, sleep quality, insomnia, and hypersomnia. Linear mixed regression models were used to explore associations between sleep features and depressive symptom severity. The z score was used to evaluate the significance of the coefficient of each feature.

RESULTS

We tested our models on the entire dataset and separately on the data of 3 different study sites. We identified 14 sleep features that were significantly (P<.05) associated with the PHQ-8 score on the entire dataset, among them awake time percentage (z=5.45, P<.001), awakening times (z=5.53, P<.001), insomnia (z=4.55, P<.001), mean sleep offset time (z=6.19, P<.001), and hypersomnia (z=5.30, P<.001) were the top 5 features ranked by z score statistics. Associations between sleep features and PHQ-8 scores varied across different sites, possibly due to differences in the populations. We observed that many of our findings were consistent with previous studies, which used other measurements to assess sleep, such as PSG and sleep questionnaires.

CONCLUSIONS

We demonstrated that several derived sleep features extracted from consumer wearable devices show potential for the remote measurement of sleep as biomarkers of depression in real-world settings. These findings may provide the basis for the development of clinical tools to passively monitor disease state and trajectory, with minimal burden on the participant.

Sleep, Narcolepsy, and Sodium Oxybate

Sodium oxybate (SO) has been in use for many decades to treat narcolepsy with cataplexy. It functions as a weak GABAB agonist but also as an energy source for the brain as a result of its metabolism to succinate and as a powerful antioxidant because of its capacity to induce the formation of NADPH. Its actions at thalamic GABAB receptors can induce slow-wave activity, while its actions at GABAB receptors on monoaminergic neurons can induce or delay REM sleep. By altering the balance between monoaminergic and cholinergic neuronal activity, SO uniquely can induce and prevent cataplexy. The formation of NADPH may enhance sleep’s restorative process by accelerating the removal of the reactive oxygen species (ROS), which accumulate during wakefulness. SO improves alertness in normal subjects and in patients with narcolepsy. SO may allay severe psychological stress - an inflammatory state triggered by increased levels of ROS and characterized by cholinergic supersensitivity and monoaminergic deficiency. SO may be able to eliminate the inflammatory state and correct the cholinergic/ monoaminergic imbalance.

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.

Aerobic Exercise and Stretching as Add-On to Inpatient Treatment for Depression Have No Differential Effects on Stress-Axis Activity, Serum-BDNF, TNF-Alpha and Objective Sleep Measures

(1) Background: While the antidepressant effects of aerobic exercise (AE) are well documented, fewer studies have examined impact of AE as an add-on treatment. Moreover, various effects on neurobiological variables have been suggested. This study examines effects of AE on Cortisol Awakening Reaction (CAR), serum Brain Derived Neurotrophic Factor (sBDNF), Tumor Necrosis Factor alpha (TNF-alpha) and sleep. (2) Methods: Inpatients with moderate-to-severe depression (N = 43) were randomly assigned to the AE or stretching condition (active control) taking place 3x/week for 6 weeks. CAR, sBDNF and TNF-alpha were assessed at baseline, after 2 weeks and post-intervention. The 17-item Hamilton Depression Rating Scale (HDRS17), subjective sleep quality measured by the Pittsburgh Sleep Quality Index (PSQI) and polysomnography (PSG) were obtained at baseline and post-intervention. (3) Results: Stress axis activity decreased in both groups from baseline to post-intervention. sBDNF showed a significant increase over time, whereas the number of awakenings significantly decreased. No significant time by group interactions were detected for any of the study variables. Correlational analyses showed that higher improvements in maximum oxygen capacity (VO₂max) from baseline to post-intervention were associated with reduced scores on the HDRS17, PSQI and REM-latency post-intervention. (4) Conclusions: While some neurobiological variables improved during inpatient treatment (CAR, sBDNF), no evidence was found for differential effects between AE and an active control condition (stretching). However, patients in which cardiorespiratory fitness increased showed higher improvements in depression severity and depression-related sleep-parameters.

The impact of antiseizure medications on polysomnographic parameters: a systematic review and meta-analysis

BACKGROUND

Oral antiseizure medications (ASMs) are first-line treatments for patients with epilepsy. However, ASMs may alter sleep architecture, adversely affecting patient outcomes. The meta-analysis aimed to elucidate the effect of ASMs on sleep architecture.

METHODS

PubMed, Embase, and Cochrane Central database (up to Febrary 2021) were searched for randomized control trials (RCT) with effects of ASMs on polysomnography parameters. A meta-analysis using a random-effects model was performed. We did not set limitation to the participants with underlying diagnosis of epilepsy.

RESULTS

Eighteen randomized-controlled trials fulfilled the eligibility criteria. The effects of five main groups of ASMs (sodium channel blockers, calcium channel blockers, GABA enhancers, synaptic vesicle glycoprotein 2A [SV2A] ligand, and broad-spetrum ASMs) on slow-wave sleep (SWS), rapid eye movement (REM) sleep, and sleep efficiency (SE) were analyzed. Compared with placebo, calcium channel blockers and GABA enhancers significantly increased SWS. GABA enhancers also decreased REM sleep percentage, whereas calcium channel blockers significantly increased SE. Sodium channel blockers, SV2A ligand and broad-spectrum ASMs did not affect SWS, REM sleep, or SE. The subgroup analysis revealed that gabapentin, pregabalin, and tiagabine increased the percentage of SWS. Tiagabine also decreased REM sleep, whereas pregabalin increased SE. Finally, levetiracetam did not affect SWS, REM sleep, and SE.

CONCLUSIONS

This meta-analysis indicated that ASMs can have a statistically significant effect on sleep parameters; the effect differs between ASMs.

Biological rhythms and chronotherapeutics in depression

Depressive syndromes are frequent and heterogeneous brain conditions with more than 90% of patients suffering from sleep complaints. Better characterizing this "sleep" domain may allow to both better treat acute episodes with existing chronotherapeutics, but also to prevent the manifestation or recurrences of mood disorders. This work aims to i) review theoretical and fundamental data of chronotherapeutics, and ii) provide practical recommendations. Light therapy (LT) can be used as a first-line monotherapy of moderate to severe depression of all subtypes. LT can be also used as a combination with antidepressant to maximize patients' response rates, which has a clear superiority to antidepressant alone. Sleep deprivation (SD) is a rapid and powerful chronotherapeutic with antidepressant responses within hours in 45-60% of patients with unipolar or bipolar depression. Different strategies should be combined to stabilize the SD antidepressant effect, including concomitant medications, repeated SD, combination with sleep phase advance and/or LT (triple chronotherapy). Melatonin treatment is of interest in remitted patients with mood disorder to prevent relapses or recurrences, if a complaint of insomnia, poor sleep quality or phase delay syndrome is associated. During the acute phase, melatonin could be used as an adjuvant treatment for symptoms of insomnia associated with depression. The cognitive behavioral therapy for insomnia (CBT-I) can be recommend to treat insomnia during euthymic phases. The Interpersonal and social rhythm therapy (IPSRT) is indicated for the acute treatment of bipolar depression and for the prevention of mood episodes. Chronotherapeutics should always be associated with behavioral measures for healthy sleep.

Cariprazine modulates sleep architecture in rats

BACKGROUND

Cariprazine is a dopamine D₃-preferring D₃/D₂ receptor partial agonist compound recently introduced to treat schizophrenia and bipolar disorder. Although cariprazine is clinically classified as a low-somnolence drug, to date no detailed polysomnographic study is available on its effect on sleep.

AIMS

This study examined the acute systemic effects of cariprazine on the rat sleep architecture and electroencephalography spectral power.

METHODS

Sprague Dawley rats were recorded during their normal sleep period for four hours, and their sleep stages were classified.

RESULTS

Cariprazine (0.3 mg/kg i.p.) reduced the time spent in rapid eye movement (REM) sleep and increased REM latency. This dose of cariprazine decreased the gamma (40-80 Hz) band frequency oscillations and increased the theta (4-9 Hz) and alpha (9-15 Hz) frequencies during the wake periods but not during slow-wave sleep. The 0.03 mg/kg dose of cariprazine only increased the alpha power during the wake periods, while the 0.003 mg/kg dose was without any effect.

CONCLUSION

Taken together, the present results suggest that the REM-suppressing effect of cariprazine may be related to its effectiveness in improving depressive symptoms, as various drugs with similar REM-reducing properties effectively treat the depressive state, whereas the gamma power-reducing effect of cariprazine may be indicative of its efficacy in schizophrenia or mania, as similar effects have been observed with other D₂ and 5-HT₂ receptor antagonist drugs. These data contribute to our understanding of the complex mechanism of action that may stand behind the clinical efficacy of cariprazine.

Exercise improves the quality of slow-wave sleep by increasing slow-wave stability

Exercise can improve sleep by reducing sleep latency and increasing slow-wave sleep (SWS). Some studies, however, report adverse effects of exercise on sleep architecture, possibly due to a wide variety of experimental conditions used. We examined the effect of exercise on quality of sleep using standardized exercise parameters and novel analytical methods. In a cross-over intervention study we examined the effect of 60 min of vigorous exercise at 60% [Formula: see text]max on the metabolic state, assessed by core body temperature and indirect calorimetry, and on sleep quality during subsequent sleep, assessed by self-reported quality of sleep and polysomnography. In a novel approach, envelope analysis was performed to assess SWS stability. Exercise increased energy expenditure throughout the following sleep phase. The subjective assessment of sleep quality was not improved by exercise. Polysomnography revealed a shorter rapid eye movement latency and reduced time spent in SWS. Detailed analysis of the sleep electro-encephalogram showed significantly increased delta power in SWS (N3) together with increased SWS stability in early sleep phases, based on delta wave envelope analysis. Although vigorous exercise does not lead to a subjective improvement in sleep quality, sleep function is improved on the basis of its effect on objective EEG parameters.

Longitudinal Changes in Sleep: Associations with Shifts in Circulating Cytokines and Emotional Distress in a Cancer Survivor Population

BACKGROUND

Sleep disturbances are associated with numerous mood disorders. Similarly, anxiety and depression are associated with modulation of the psychoneuroimmune (PNI) axis. This study hypothesized that changes in both monitored and self-reported measures of sleep would relate to changes in circulating cytokine levels in an emotionally distressed population of cervical cancer survivors.

METHODS

Biospecimens, patient-reported outcome (PRO) measures, and actigraphy were collected from cervical cancer survivors enrolled in a biobehavioral clinical trial. Longitudinal changes over a 4-month period were examined. Sleep time measured by actigraphy and PRO were analyzed for correlative changes with emotional distress and serum cytokines (n = 71).

RESULTS

Longitudinal change in the actigraph measure of sleep time was inversely associated with changes in depression and anxiety (test for linear trend, p = 0.02 and p = 0.05 respectively), as well as acute-phase response/pro-inflammatory cytokines (test for linear trend, p = 0.003, interleukin (IL)-2; 0.022, IL-1β; 0.0002, IL-6; and 0.049, tumor necrosis factor α). Conversely, changes in self-reported sleep problems were related to an increase in depression and anxiety (p = 0.001 and p = 0.01 respectively), the T helper 2 (Th2) cytokine IL-5 (p = 0.027), and the counter-regulatory cytokine IL-10 (0.016).

CONCLUSION

This study showed that an increase in sleep time or decrease in sleep problems corresponded with a reduction in self-reported emotional distress and attenuation of pro-inflammatory, Th2, and counter-regulatory cytokines. Our results support sleep measurement as a meaningful biobehavioral variable in cancer survivorship. This study also indicates that sleep investigators should be aware that choice of methodology might influence concordance with different classes of immune parameters.

Is moderate depression associated with sleep stage architecture in adolescence? Testing the stage type associations using network and transition probability approaches

BACKGROUND

Depression even at the subclinical level is often accompanied by sleep disturbances, but little is known about the dynamics of the sleep stages in relation to depressive symptoms. We examined whether the amount, associations, and transition probabilities of various sleep stages were associated with depressive symptoms in a community sample of adolescents.

METHODS

The participants (N = 172, 59% girls, mean age 16.9 years) underwent overnight polysomnography and provided data on depressive symptoms (Beck Depression Inventory II). The association between depression status and total duration of each stage type was analyzed using ANOVA and survival analyses. The associations between the number of different sleep stage types were analyzed using graphical Gaussian models, mixed graphical models, and relative importance networks. A Markov chain algorithm was used to estimate the transition probabilities between each state and these probabilities were further compared between depression status groups.

RESULTS

The associations between N1 and N3 were significantly stronger in both directions of the association (p-values for interactions 0.012 and 0.006) in those with more depressive symptoms. Similarly, a stronger association was observed from N1 to wake stage in those with more depressive symptoms (p-value for interaction 0.002). In those with more depressive symptoms, it was more likely to transition from N2 to N3 and from REM to N2 compared to others.

CONCLUSIONS

These findings indicate that changes in sleep architecture are not limited to clinical depression and that the transitional dynamics of sleep stages are an important marker of subclinical depression.

Sleep disturbances in obsessive-compulsive disorder: influence of depression symptoms and trait anxiety

BACKGROUND

Sleep disturbances have been reported in obsessive-compulsive disorder (OCD) patients, with heterogeneous results. The aim of our study was to assess sleep function in OCD and to investigate the relationship between sleep and the severity of obsessive-compulsive (OC) symptoms, depressive symptoms and trait anxiety.

METHODS

Sleep quality was measured in 61 OCD patients and 100 healthy controls (HCs) using the Pittsburgh Sleep Quality Index (PSQI). Multiple linear regression was conducted to explore the association between sleep and psychopathological measures; a mediation analysis was also performed.

RESULTS

OCD patients showed poor sleep quality and more sleep disturbances compared to HCs. The severity of depression, trait anxiety and OC symptomatology were correlated with poor sleep quality. Multiple linear regression analyses controlling for potential confounders revealed that the severity of depression and trait anxiety were independently related to poor sleep quality in OCD. A mediation analysis showed that both the severity of trait anxiety and depression mediate the relationship between the severity of OC symptoms and poor sleep quality among patients with OCD.

CONCLUSIONS

Our findings support the existence of sleep disturbances in OCD. Trait anxiety and depression play a key role in sleep quality among OCD patients.

Differential Co-Occurring Patterns Between Depressive Symptomatology and Sleep-Wake-Related Disturbances in Mood Disorders

PURPOSE

This study aimed to elucidate the various co-occurring patterns of depressive symptomatology and sleep-wake-related disturbances (SWRDs) in patients with mood disorders.

PATIENTS AND METHODS

Individuals in non-acute states of major depressive disorder or bipolar disorder were recruited. The Beck Depression Inventory II (BDI-II) was utilized to evaluate depressive symptoms. BDI-II items were classified into three domains: cognitive, affective, and somatic. Between-domain differences with various SWRDs were examined. Latent class analysis was used to empirically classify participants using BDI-II items as indicator variables. Co-occurring patterns between domains of BDI-II items and SWRDs were re-examined in each subgroup to elucidate inter-individual differences.

RESULTS

In total, 657 participants were enrolled. Of participants, 66.8% were female, and 52.4% were diagnosed with major depressive disorder. Each BDI-II domain exhibited different co-occurring patterns. The somatic domain was most likely to co-occur with various SWRDs. Three subgroups were derived from latent class analysis and were designated as poor sleep quality and high insomnia (n=150), poor sleep quality and moderate insomnia (n=248), and poor sleep quality and low insomnia (n=159). The group with more severe insomnia presented with more severe depressive and anxiety symptoms. The three subgroups further differed in co-occurring patterns. From the low insomnia to high insomnia group, the associations with various SWRDs appeared in the sequence of somatic, affective, and cognitive domains.

CONCLUSION

Co-occurring patterns between domains of depressive symptomatology with various SWRDs differ and may vary among individuals.

Rapid Eye Movement Sleep Deprivation Combined With Fluoxetine Protects Against Depression-Induced Damage and Apoptosis in Rat Hippocampi via A1 Adenosine Receptor

Background: Rapid eye movement sleep deprivation (REMSD) and fluoxetine affect depression, yet the detailed molecular mechanisms were not clear. Methods: Rat depression chronic unpredictable stress was constructed, and the body weight of rats was measured. The efficacy of REMSD and fluoxetine on the pleasure experience, exploration, and cognition of rats with depression was determined by the Sucrose preference test, the open field test, and Morris water task, respectively. The effects of REMSD and fluoxetine on depression-induced damage and apoptosis in rat hippocampi were detected using hematoxylin-eosin staining and terminal transferase-mediated biotin 2'-deoxyuridine, 5'-triphosphate nick end labeling. A1 adenosine receptor content was measured by immunohistochemistry. Relative expressions of the A1 adenosine receptor, proteins related to apoptosis (B Bcl-2-associated X protein; B-cell lymphoma 2), phosphoinositide 3-kinase, P38 mitogen-activated protein kinase, cFos, and adenosine deaminase RNA specific two were quantified by quantitative real-time polymerase chain reaction and Western blot as needed. Results: Depression decreased rat weight. REMSD combined with fluoxetine increased body weight, prompted rat behavior, alleviated depression-induced damage, attenuated apoptosis, and promoted A1 adenosine receptor level in rat hippocampi. Furthermore, the combined therapy upregulated expressions of A1 adenosine receptor, B-cell lymphoma 2, and phosphoinositide 3-kinase but downregulated those of B-cell lymphoma 2-associated X protein, P38 mitogen-activated protein kinase, cFos, and adenosine deaminase RNA specific 2 in the hippocampi of rats with depression. Conclusion:REMSD combined with fluoxetine protected rats against depression-induced damage and apoptosis in the hippocampus via the A1 adenosine receptor, providing a possible treatment strategy for depression.

Resilience as the Mediating Factor in the Relationship Between Sleep Disturbance and Post-stroke Depression of Stroke Patients in China: A Structural Equation Modeling Analysis

Background: Stroke patients may suffer from a variety of symptoms which can result in sleep disturbance and post-stroke depression (PSD). Whereas, resilience can alleviate sleep disturbance and help maintain well-being after stroke. Objective: The aim of this study is to explore whether resilience plays a mediating role in the relationship between sleep disturbance and PSD of stroke patients in China. Methods: A cross-sectional study with a multi-stage sampling was carried out in Liaoning Rehabilitation Center and the Third People's Hospital of Chongqing in China from May to September 2019. A total of 353 stroke patients were enrolled in this study. Structural equation model (SEM) was used to test the mediating effect of resilience on the relationship between sleep disturbance and PSD. Results: The prevalence of PSD of stroke patients was 34.56%. Sleep disturbance contributed most to the variance of PSD and had a significantly positive association with PSD among stroke patients (P < 0.01). Resilience was negatively associated with PSD, and acted as a mediator between sleep disturbance and PSD (a ^* b = 0.201, BCa 95% CI: 0.156~0.254). Conclusions: The prevalence of PSD was high among the Chinese stroke patients. Sleep disturbance was highly associated with PSD, resulting in the increased risk of PSD. Furthermore, resilience has a mediating effect on the relationship between sleep disturbance and PSD, and could reduce the negative effect of sleep disturbance on the development of PSD.

Using EEG to Predict Clinical Response to Electroconvulsive Therapy in Patients With Major Depression: A Comprehensive Review

Introduction: An important approach to improve the therapeutic effect of electroconvulsive therapy (ECT) may be to early characterize patients who are more likely to respond. Our objective was to explore whether baseline electroencephalography (EEG) settings before the beginning of ECT treatment can predict future clinical response to ECT in patients with depressive disorder. Methods: We conducted a systematic search in the MEDLINE, EMBASE, PsycINFO, Web of Science, and Cochrane Central Register of Controlled Trials (CENTRAL) databases to identify studies using EEG in adults with depressive disorder treated by ECT. To investigate the predictive value of baseline EEG on clinical outcomes of ECT, we extracted from the retrieved studies and qualitatively described the association between the baseline EEG markers characteristics and the rates of future responders and/or remitters to ECT. Results: The primary search yielded 2,531 potentially relevant citations, and 12 articles were selected according to inclusion criteria. Most of the studies were prospective studies with small sample size. Sociodemographic and clinical characteristics of patients, ECT settings, EEG settings, and outcomes were heterogeneous. Event-related potential (ERP) paradigms were used in three studies, polysomnography was used in three studies, and the six other studies used EEG to measure cerebral connectivity and activity. Conclusions: P300 amplitude, coherence, and connectivity measures were correlated with remission in patients with depression treated by ECT. Sleep EEG recordings seemed not to be correlated with remission after ECT. Further prospective studies with large sample size are needed to determine optimal EEG parameters associated with clinical response to ECT in depressive disorder. Systematic Review Registration: PROSPERO CRD42020181978.

Sleep Monitoring Using WatchPAT Device to Predict Recurrence of Major Depression in Patients at High Risk for Major Depression Disorder Recurrence: A Case Report

Background: Major depressive disorders are strongly correlated with alterations in sleep pattern and architecture, including changes in the Rapid Eye Movement (REM) phase. However, it is still unknown whether sleep alterations precede other depression-related symptoms, particularly in patients with recurrent depressive episodes at relapse risk. Case Presentation: We initiated a study aimed at examining the value of ambulatory sleep monitoring using a WatchPAT device, in predicting recurrence of Major depression. Depression was assessed monthly with the Beck Depression Inventory version II (BDI-II). Here we present the case of a 63 years old woman, with a history of recurrent depressive episodes. AT the time of recruitment, she was asymptomatic, she experienced recurrence of Major depression 3 months into the study. We observed a significant reduction of the Rem Latency parameters 5 weeks prior to BDI-II score increase, reflecting major depressive episode recurrence. Conclusion: Though our results are preliminary, they suggest that ambulatory sleep monitoring can be used as a simple and accessible tool, predicting recurrence of Major Depressive episodes in patients at high risk, thus enabling early treatment intervention.

REM density is associated with treatment response in major depression: Antidepressant pharmacotherapy vs. psychotherapy

Major depression is one of the most common psychiatric illnesses. Interestingly, a few studies have indicated the existence of depression subgroups, which respond differently to the available treatment options. Previously, sleep abnormalities have been suggested to indicate amenability to different treatment regimens. Thereby, especially REM-sleep parameters seem to play a prominent role, and REM-sleep dysregulation has been repeatedly discussed as a potential endophenotype of depression. With that said, estimating therapy outcome in order to choose the best line of treatment is of utmost importance to patients suffering from depression. The present study looks deeper into these clues by investigating the capability of polysomnographic sleep parameters to predict treatment response in depressed patients to either pharmacotherapy or psychotherapy. Moderately to severely depressed patients (n = 38) were randomly assigned to either psychotherapy (i.e. interpersonal psychotherapy) or pharmacotherapy (i.e., monotherapy with selective serotonin reuptake inhibitors, SSRI, or selective serotonin noradrenalin reuptake inhibitors, SSNRI). Prior to treatment, all patients underwent polysomnography in the sleep laboratory. After treatment, responders and non-responders of both treatment groups were compared regarding their baseline sleep parameters. Higher baseline REM density, i.e. the amount of rapid eye movements during REM sleep, predicted better response to antidepressant pharmacotherapy. In the psychotherapy group, the effect seemed reversed but was not statistically significant. No other sleep parameter predicted treatment response. Our findings support the notion that REM-sleep dysregulation is indeed indicative of a distinct endophenotype of depression and that pharmacotherapy with SSRI/SSNRI might be superior to psychotherapy in these patients.

The Effects of Daytime Psilocybin Administration on Sleep: Implications for Antidepressant Action

Serotonergic agonist psilocybin is a psychedelic with antidepressant potential. Sleep may interact with psilocybin’s antidepressant properties like other antidepressant drugs via induction of neuroplasticity. The main aim of the study was to evaluate the effect of psilocybin on sleep architecture on the night after psilocybin administration. Regarding the potential antidepressant properties, we hypothesized that psilocybin, similar to other classical antidepressants, would reduce rapid eye movement (REM) sleep and prolong REM sleep latency. Moreover, we also hypothesized that psilocybin would promote slow-wave activity (SWA) expression in the first sleep cycle, a marker of sleep-related neuroplasticity. Twenty healthy volunteers (10 women, age 28–53) underwent two drug administration sessions, psilocybin or placebo, in a randomized, double-blinded design. Changes in sleep macrostructure, SWA during the first sleep cycle, whole night EEG spectral power across frequencies in non-rapid eye movement (NREM) and REM sleep, and changes in subjective sleep measures were analyzed. The results revealed prolonged REM sleep latency after psilocybin administration and a trend toward a decrease in overall REM sleep duration. No changes in NREM sleep were observed. Psilocybin did not affect EEG power spectra in NREM or REM sleep when examined across the whole night. However, psilocybin suppressed SWA in the first sleep cycle. No evidence was found for sleep-related neuroplasticity, however, a different dosage, timing, effect on homeostatic regulation of sleep, or other mechanisms related to antidepressant effects may play a role. Overall, this study suggests that potential antidepressant properties of psilocybin might be related to changes in sleep.