Hypersomnia and depressive symptoms: methodological and clinical aspects

Effects of Sleep Deficiency on Risk, Course, and Treatment of Psychopathology

This article reviews the literature on the relationship between sleep deficiency and unipolar and bipolar depression, anxiety disorders, and posttraumatic stress disorder. We consider the evidence for sleep as a contributory causal factor in the development of psychiatric disorders, as well as sleep as an influential factor related to the outcome and recurrence of psychopathology. A case for sleep deficiency being an important treatment target when sleep and psychiatric disorders are comorbid is also made. Our recommendation is that sleep deficiency is recognized as a means to positively impact the development and course of psychopathology and, as such, is routinely assessed and treated in clinical practice.

Sleep disorders and Parkinson's disease: is there a right direction?

In the last years, the hypothesis of a close relationship between sleep disorders (SDs) and Parkinson's disease (PD) has significantly strengthened. Whether this association is causal has been also highlighted by recent evidence demonstrating a neurobiological link between SDs and PD. Thus, the question is not whether these two chronic conditions are mutually connected, but rather how and when this relationship is expressed. Supporting this, not all SDs manifest with the same temporal sequence in PD patients. Indeed, SDs can precede or occur concomitantly with the onset of the clinical manifestation of PD. This review discusses the existing literature, putting under a magnifying glass the timing of occurrence of SDs in PD-neurodegeneration. Based on this, here, we propose two possible directions for studying the SDs-PD relationship: the first direction, from SDs to PD, considers SDs as potential biomarker/precursor of future PD-neurodegeneration; the second direction, from PD to SDs, considers SDs as concomitant symptoms in manifest PD, mainly related to primary PD-neuropathology and/or parkinsonian drugs. Furthermore, for each direction, we questioned SDs-PD relationship in terms of risk factors, neuronal circuits/mechanisms, and impact on the clinical phenotype and disease progression. Future research is needed to investigate whether targeting sleep may be the winning strategy to treat PD, in the context of a personalized precision medicine.

Depressive symptoms in patients with hypersomnia measured with Beck Depression Inventory

BACKGROUND

Patients with central hypersomnia (HCO) often show symptoms of depression. Despite of many studies conducted in this field, the link between these two disorders remains unclear. In order to contribute data to this research, we examined the question of which depressive symptoms characterize these patients. Furthermore, we investigated the differences between HCO who were more or less depressed regarding insomnia, sleep quality and daytime tiredness.

METHODS AND MATERIAL

The retrospective analysis assesses the presence and kind of depressive symptoms as measured by the Beck Depression Inventory (BDI) in 168 HCO including narcolepsy type I (NAR1), narcolepsy type II (NAR2) and idiopathic hypersomnia (HYP). Sleep parameters from one night of polysomnography, scores of questionnaires for insomnia and for daytime sleepiness, and data from sustained attention tests were compared between HCO with and without depression, as determined by BDI scores (cut off >12).

RESULTS

According to BDI scores 52% exhibited no depression. The BDI items pertaining to tiredness and work inhibition exhibited elevated scores, whereas those pertaining to suicidality showed low scores. No difference was found between depressed and non-depressed HCO with regard to daytime vigilance performance or daytime sleepiness. However, depression was associated with older age, higher insomnia scores, and a shorter sleep time on polysomnography.

CONCLUSION

A potential interpretation of our findings is that depressive symptoms in HCO may be a consequence of restricted life quality due to hypersomnia. Thus, therapeutical effort should focus more intensely on coping strategies.

Predicting Depression Among Chinese Patients with Narcolepsy Type 1: A Machine-Learning Approach

Objective

Depression is a common psychiatric issue among patients with narcolepsy type 1 (NT1). Effective management requires accurate screening and prediction of depression in NT1 patients. This study aims to identify relevant factors for predicting depression in Chinese NT1 patients using machine learning (ML) approaches.

Methods

A total of 203 drug-free NT1 patients (aged 5-61), diagnosed based on the ICSD-3 criteria, were consecutively recruited from the Sleep Medicine Center at Peking University People's Hospital between September 2019 and April 2023. Depression, daytime sleepiness, and impulsivity were assessed using the Center for Epidemiologic Studies Depression Scale for Children (CES-DC) or the Self-Rating Depression Scale (SDS), the Epworth Sleepiness Scale for adult or children and adolescents (ESS or ESS-CHAD), and the Barratt Impulse Scale (BIS-11). Demographic characteristics and objective sleep parameters were also analyzed. Three ML models-Logistic Regression (LR), Random Forest (RF), and Support Vector Machine (SVM)-were used to predict depression. Model performance was evaluated using receiver operating curve (AUC), accuracy, precision, recall, F1 score, and decision curve analysis (DCA).

Results

The LR model identified hallucinations (OR 2.21, 95% CI 1.01-4.90, p = 0.048) and motor impulsivity (OR 1.10, 95% CI 1.02-1.18, p = 0.015) as predictors of depression. Among the ML models, SVM showed the best performance with an AUC of 0.653, accuracy of 0.659, sensitivity of 0.727, and F1 score of 0.696, reflecting its effectiveness in integrating sleep-related and psychosocial factors.

Conclusion

This study highlights the potential of ML models for predicting depression in NT1 patients. The SVM model shows promise in identifying patients at high risk of depression, offering a foundation for developing a data-driven, personalized decision-making tool. Further research should validate these findings in diverse populations and include additional psychological variables to enhance model accuracy.

The electroretinography to identify biomarkers of idiopathic hypersomnia and narcolepsy type 1

Hypersomnia spectrum disorders are underdiagnosed and poorly treated due to their heterogeneity and absence of biomarkers. The electroretinography has been proposed as a proxy of central dysfunction and has proved to be valuable to differentiate certain psychiatric disorders. Hypersomnolence is a shared core feature in central hypersomnia and psychiatric disorders. We therefore aimed to identify biomarkers by studying the electroretinography profile in patients with narcolepsy type 1, idiopathic hypersomnia and in controls. Cone, rod and retinal ganglion cells electrical activity were recorded with flash-electroretinography in non-dilated eye of 31 patients with idiopathic hypersomnia (women 84%, 26.6 ± 5.9 years), 19 patients with narcolepsy type 1 (women 63%, 36.6 ± 12.7 years) and 43 controls (women 58%, 30.6 ± 9.3 years). Reduced cone a-wave amplitude (p = 0.039) and prolonged cone (p = 0.022) and rod b-wave (p = 0.009) latencies were observed in patients with narcolepsy type 1 as compared with controls, while prolonged photopic negative response-wave latency (retinal ganglion cells activity) was observed in patients with idiopathic hypersomnia as compared with controls (p = 0.033). The rod and cone b-wave latency clearly distinguished narcolepsy type 1 from idiopathic hypersomnia and controls (area under the curve > 0.70), and the photopic negative response-wave latency distinguished idiopathic hypersomnia and narcolepsy type 1 from controls with an area under the curve > 0.68. This first original study shows electroretinography anomalies observed in patients with hypersomnia. Narcolepsy type 1 is associated with impaired cone and rod responses, whereas idiopathic hypersomnia is associated with impaired retinal ganglion cells response, suggesting different phototransduction alterations in both hypersomnias. Although these results need to be confirmed with a larger sample size, the electroretinography may be a promising tool for clinicians to differentiate hypersomnia subtypes.

Dosing Optimization of Low-Sodium Oxybate in Narcolepsy and Idiopathic Hypersomnia in Adults: Consensus Recommendations

INTRODUCTION

Low-sodium oxybate (LXB) is approved for treatment of narcolepsy in patients aged 7 years and older and treatment of idiopathic hypersomnia in adults. LXB contains the same active moiety with 92% less sodium than sodium oxybate (SXB). As the indication for oxybate treatment in patients with idiopathic hypersomnia is new and allows for individualized dosing optimization, guidance for beginning LXB treatment is needed. In particular, clinicians may benefit from guidance regarding treatment initiation, dosing/regimen options, potential challenges, and treatment expectations. Additionally, pharmacokinetic profiles differ slightly between both treatments, and further guidance on transitioning from SXB to LXB in patients with narcolepsy may aid clinicians.

METHODS

An expert panel of five sleep specialists was convened to obtain consensus on recommendations for these topics using a modified Delphi process.

RESULTS

Across two virtual meetings, the panel agreed on 31 recommendations with a high degree of consensus that fell into four overarching topics: (1) introducing LXB to patients; (2) initiating LXB for adult narcolepsy and idiopathic hypersomnia; (3) addressing challenges in using LXB; and (4) transitioning from SXB to LXB. The panel recommended that clinicians provide a clear overview of how LXB works for treating symptoms in narcolepsy or idiopathic hypersomnia, as appropriate for their patients, explain safety aspects, and set expectations prior to initiating LXB treatment. Strategies for initial dosing and regimen are provided. Strategies for adjusting the dose, regimen, timing, and consideration of individual factors were developed for specific instances in which patients may have trouble staying asleep or waking up, as well as guidance for addressing potential adverse events, such as nausea, dizziness, anxiety, and depression. Discussion points based on existing literature and clinical experience were included as relevant for each statement.

CONCLUSION

Clinicians may use this resource to guide LXB dosing optimization with patients.

Sleepiness and comorbid sleep disorders in functional motor disorders: a comparative study with central hypersomnia

Sleep symptoms, including excessive sleepiness, are frequently reported by patients with functional motor disorders (FMD). We aimed to classify the comorbid sleep disorders in FMD, and to investigate the relationship between subjective sleepiness and objective measures of hypersomnia, comparing them with data from people with central hypersomnia. A total of 37 patients (mean [SD] age 46.4 [11.2] years) with clinically definite FMD, and 17 patients (mean [SD] age 41.1 [11.6] years) with central hypersomnia underwent structured medical and sleep history, neurological examination, polysomnography, multiple sleep latency test (MSLT), and questionnaires assessing sleepiness, fatigue, and depression. In all, 23 patients with FMD (62%) reported excessive daytime sleepiness. Evidence of specific sleep disorders was identified in our cohort, with 35% having restless legs syndrome; 49% obstructive sleep apnea; and 8% periodic limb movements in sleep; however, the presence of these disorders was not correlated with subjective sleepiness. Patients with FMD with self-reported sleepiness reported higher fatigue (p = 0.002), depression (p = 0.002), and had longer sleep latencies in the MSLT (p < 0.001) compared to the patients with central hypersomnia. No correlation was found between subjective and objective sleepiness in either group. Fatigue positively correlated with self-reported sleepiness in patients with FMD (p < 0.001). This study did not find objective correlates of increased sleepiness in patients with FMD. While sleep abnormalities were found to be common in FMD, they were not correlated with self-reports of excessive sleepiness. Positive correlations between self-reported sleepiness and fatigue support the current unified model of non-motor symptoms in FMD.

Prevalence and Course of Idiopathic Hypersomnia in the Wisconsin Sleep Cohort Study

BACKGROUND AND OBJECTIVES

Idiopathic hypersomnia (IH) is a CNS disorder of hypersomnolence of unknown etiology. Due to the requirement for objective sleep testing to diagnose the disorder, there are currently no population-based estimates of the prevalence of IH nor data regarding the longitudinal course of IH in naturalistic settings.

METHODS

Subjective and objective data from the Wisconsin Sleep Cohort study were used to identify cases with probable IH from participants with polysomnography and multiple sleep latency test data. Demographic, polysomnographic, and symptom-level data were compared between those with and without IH. Longitudinal trajectories of daytime sleepiness among those with IH were assessed to evaluate symptom persistence or remission over time.

RESULTS

From 792 cohort study participants with available polysomnography and multiple sleep latency test data, 12 cases with probable IH were identified resulting in an estimated prevalence of IH of 1.5% (95% CI 0.7-2.5, p < 0.0001). Consistent with inclusion/exclusion criteria, cases with IH had more severe sleepiness and sleep propensity, despite similar or longer sleep times. Longitudinal data (spanning 12.1 ± 4.3 years) demonstrated a chronic course of sleepiness for most of the cases with IH, though pathologic somnolence remitted in roughly 40% of cases.

DISCUSSION

These results demonstrate IH is more common in the working population than generally assumed with a prevalence on par with other common neurologic and psychiatric conditions. Further efforts to identify and diagnose those impaired by unexplained daytime somnolence may help clarify the causes of IH and the mechanisms underlying symptomatic remission.

Narcolepsies, update in 2023

Narcolepsy type 1 (NT1) and type 2 (NT2), also known as narcolepsy with and without cataplexy, are sleep disorders that benefited from major scientific advances over the last two decades. NT1 is caused by the loss of hypothalamic neurons producing orexin/hypocretin, a neurotransmitter regulating sleep and wake, which can be measured in the cerebrospinal fluid (CSF). A low CSF level of hypocretin-1/orexin-A is a highly specific and sensitive biomarker, sufficient to diagnose NT1. Orexin-deficiency is responsible for the main NT1 symptoms: sleepiness, cataplexy, disrupted nocturnal sleep, sleep-related hallucinations, and sleep paralysis. In the absence of a lumbar puncture, the diagnosis is based on neurophysiological tests (nocturnal and diurnal) and the presence of the pathognomonic symptom cataplexy. In the revised version of the International Classification of sleep Disorders, 3rd edition (ICSD-3-TR), a sleep onset rapid eye movement sleep (REM) period (SOREMP) (i.e. rapid occurrence of REM sleep) during the previous polysomnography may replace the diurnal multiple sleep latency test, when clear-cut cataplexy is present. A nocturnal SOREMP is very specific but not sensitive enough, and the diagnosis of cataplexy is usually based on clinical interview. It is thus of crucial importance to define typical versus atypical cataplectic attacks, and a list of clinical features and related degrees of certainty is proposed in this paper (expert opinion). The time frame of at least three months of evolution of sleepiness to diagnose NT1 was removed in the ICSD-3-TR, when clear-cut cataplexy or orexin-deficiency are established. However, it was kept for NT2 diagnosis, a less well-characterized disorder with unknown clinical course and absence of biolo biomarkers; sleep deprivation, shift working and substances intake being major differential diagnoses. Treatment of narcolepsy is nowadays only symptomatic, but the upcoming arrival of non-peptide orexin receptor-2 agonists should be a revolution in the management of these rare sleep diseases.

Eyelid Closure Behavior of Patients with Idiopathic and Nonorganic Hypersomnia, Narcolepsy-Cataplexy, and Healthy Controls in the Maintenance of Wakefulness Test

Purpose

Differential diagnosis of central disorders of hypersomnolence remains challenging, particularly between idiopathic (IH) and nonorganic hypersomnia (NOH). We hypothesized that eyelid closure behavior in the maintenance of wakefulness test (MWT) could be a valuable biomarker.

Patients and Methods

MWT recordings of patients with IH, NOH, narcolepsy-cataplexy (NC), and healthy sleep-deprived controls (H) were retrospectively analyzed (15 individuals per group). For each MWT trial, visual scoring of face videography for partial (50-80%) and full eyelid closure (≥80%) was performed from "lights off" to the first microsleep episode (≥3 s).

Results

In all groups, the frequency and cumulative duration of periods with partial and full eyelid closure gradually increased toward the first microsleep episode. On the group level, significant differences occurred for the latency to the first microsleep episode (IH 21 min (18-33), NOH 23 min (17-35), NC 11 min (7-19), H 10 min (6-25); p = 0.009), the ratio between partial and full eyelid closure duration (IH 2.2 (0.9-3.1), NOH 0.5 (0-1.2), NC 2.8 (1.1-5), H 0.7 (0.4-3.3); p = 0.004), and the difference between full and partial eyelid closure duration in the five minutes prior to the first microsleep episode (∆full - partial eyelid closure duration: IH -16 s (-35 to 28); NOH 46 s (9-82); NC -6 s (-26 to 5); H 10 s (-4 to 18); p = 0.007). IH and NOH significantly differed comparing the ratio between partial and full eyelid closure (p = 0.005) and the difference between ∆full - partial eyelid closure duration in the five minutes prior to the first microsleep episode (p = 0.006).

Conclusion

In the MWT, eyelid closure behavior (∆full - partial) in the period prior to the first microsleep episode could be of value for discriminating NOH from other etiologies of excessive daytime sleepiness, particularly IH.

Prevalence of Depressive Symptoms Among an Undergraduate Health Sciences Student Population: A Cross-Sectional Study

PURPOSE

Undergraduate health sciences students are irrefutably liable to intrapersonal tension that may provoke the almost imperceptible onset and incremental expansion of depressive symptoms. Mental health is often a deplorably neglected topic despite posing as a catalyst in many students' academic demise. Thus, the primary objective of this paper is to provide an insight into a multitude of variables that foster depressive symptoms. In doing so, the scope of subclinical depression that could be hindering a student's academic performance shall be illuminated.

METHODOLOGY

A cross-sectional study was conducted among health sciences students comprising both genders, any nationality, students 18 years of age or older, and students within their first three years of undergraduate study. The well-established Patient Health Questionnaire-9 was distributed along with a non-standardized questionnaire that inquires about additional risk factors. The chi-square test method was used to associate the dependent and independent variables, and statistical significance was done at p-value ≤ 0.05.

FINDINGS

It was observed that 34.8% of participants suffer depressive symptoms. Participants' sex and marital status, among many other factors, like age, program and year of study, are found to be statistically insignificant. Conversely, nationality, university-related workload, smoking, alcohol intake and more are noted to be significantly associated with the development of depressive symptoms.

ORIGINALITY

This study is an original work done by the authors to investigate the prevalence of depressive symptoms among undergraduate health sciences students. The non-standardized questionnaire employed has been reviewed to ensure that it is without discrimination of any gender or biased towards any stakeholders.

Associations between individual depressive symptoms and immunometabolic characteristics in major depression

Inflammation and metabolic dysregulations are likely to underlie atypical, energy-related depressive symptoms such as appetite and sleep alterations. Indeed, increased appetite was previously identified as a core symptom of an immunometabolic subtype of depression. The aim of this study was 1) to replicate the associations between individual depressive symptoms and immunometabolic markers, 2) to extend previous findings with additional markers, and 3) to evaluate the relative contribution of these markers to depressive symptoms. We analyzed data from 266 persons with major depressive disorder (MDD) in the last 12 months from the German Health Interview and Examination Survey for Adults and its mental health module. Diagnosis of MDD and individual depressive symptoms were determined by the Composite International Diagnostic Interview. Associations were analyzed using multivariable regression models, adjusting for depression severity, sociodemographic/behavioral variables, and medication use. Increased appetite was associated with higher body mass index (BMI), waist circumference (WC), insulin, and lower high-density lipoprotein. In contrast, decreased appetite was associated with lower BMI, WC, and fewer metabolic syndrome (MetS) components. Insomnia was associated with higher BMI, WC, number of MetS components, triglycerides, insulin, and lower albumin, while hypersomnia was associated with higher insulin. Suicidal ideation was associated with higher number of MetS components, glucose, and insulin. None of the symptoms were associated with C-reactive protein after adjustment. Appetite alterations and insomnia were most important symptoms associated with metabolic markers. Longitudinal studies should investigate whether the candidate symptoms identified here are predicted by or predict the development of metabolic pathology in MDD.

Shift work schedule and sleep patterns in relation to incident depression: Evidence from a prospective cohort study

This study aims to explore the joint associations of shift work and sleep patterns with incident depression. The present prospective cohort using data from UK biobank, included 220,651 participants aged 38 to 71 years recruited between 2006 and 2010. Every participant finished a self-completed touch-screen questionnaire. Hazards ratios (HRs) with corresponding 95% confidence intervals (CIs) of incident depression were reported for shift work and sleep patterns by Cox-proportional hazard models. The average follow-up time was 12.13±1.94 years and the incidence rate of depression was 2.95 (2.89-3.02) per 1000 person-years. After fully adjustment, the participants with irregular and permanent night shifts companied by any sleep pattern were significantly associated with increased risk of incident depression compared with no shift work companied by favorable sleep patterns. The females seemed to be more vulnerable when having night shifts and unfavorable sleep patterns compared with the males. The increased risk of incident depression associated with shift work regardless of night shifts and evening/weekend shifts was not able to offset by favorable sleep patterns. The workers with unhealthy sleep patterns, especially inappropriate sleep duration and insomnia companied by shift work schedule should be paid more attention considering higher risk of depression.

Prevalence of depression and anxiety, and associated factors, among Chinese primary and high school students: A cross-sectional, epidemiological study

INTRODUCTION

This study aimed to investigate the prevalence of depression and anxiety, and associated factors, among Chinese children and adolescents aged 8-18 years who attend primary or high school.

METHODS

A total of 23 005 primary and high school students were recruited from February to December, 2019 for this cross-sectional study. The questionnaire included demographic information, questions assessing suicidality, resilience, depression (Center for Epidemiological Studies Depression Scale for Children), and anxiety (Screen for Child Anxiety Related Disorders). Binary logistic regression was used to analyze the independent correlates of depression and anxiety.

RESULTS

Overall, 13.06% of participants experienced depressive symptoms, 22.34% experienced anxiety symptoms, 26.34% experienced transient suicidal ideation, 2.23% had serious suicidal ideation, and 1.46% had a history of suicide attempts. Anxiety (odds ratio [OR], 4.935; 95% confidence interval [CI][4.442-5.485]), suicidality (OR, 2.671; 95% CI[2.203-3.237]), skipping breakfast (OR, 1.920; 95% CI[1.348-2.736]), sleep duration (OR, 0.470; 95% CI[0.398-0.556]) and self-expectations (OR, 1.924; 95% CI[1.550-2.389]) were associated with depression (all p < .05). Depression (OR, 4.424; 95% CI[3.983-4.914]), female sex (OR, 1.903; 95% CI[1.759-2.060]), school-based traumatic experience(s) (OR, 1.905; 95% CI[1.747-2.077]), relationships with teachers (OR, 1.575; 95% CI[1.103-2.249]), and suicidality (OR, 1.467; 95% CI[1.218-1.766]) were associated with anxiety symptoms (all p < .05).

DISCUSSION

Depression and anxiety are common among school-age children and adolescents in China. Childhood school- and family-based traumatic experience(s), female sex, and lifestyle factors (eating breakfast, sleep duration, exercising, and Internet use) are significantly associated with mental health among children and adolescents. Developing interventions targeting these factors to protect students from depression and anxiety are needed.

Sleep disturbance as a transdiagnostic marker of psychiatric risk in children with neurodevelopmental risk genetic conditions

Children with rare neurodevelopmental genetic conditions (ND-GCs) are at high risk for a range of neuropsychiatric conditions. Sleep symptomatology may represent a transdiagnostic risk indicator within this patient group. Here we present data from 629 children with ND-GCs, recruited via the United Kingdom's National Health Service medical genetic clinics. Sibling controls (183) were also invited to take part. Detailed assessments were conducted to characterise the sleep phenotype of children with ND-GCs in comparison to controls. Latent class analysis was conducted to derive subgroups of children with an ND-GC based on sleep symptomatology. Assessment of cognition and psychopathology allowed investigation of whether the sleep phenotypic subgroup was associated with neuropsychiatric outcomes. We found that children with an ND-GC, when compared to control siblings, were at elevated risk of insomnia (ND-GC = 41% vs Controls = 17%, p < 0.001) and of experiencing at least one sleep symptom (ND-GC = 66% vs Controls = 39%, p < 0.001). On average, insomnia was found to have an early onset (2.8 years) in children with an ND-GC and to impact across multiple contexts. Children in subgroups linked to high sleep symptomatology were also at high risk of psychiatric outcomes (OR ranging from 2.0 to 21.5 depending on psychiatric condition). Our findings demonstrate that children with high genetic vulnerability for neurodevelopmental outcomes exhibit high rates of insomnia and sleep symptomatology. Sleep disruption has wide-ranging impacts on psychosocial function, and indexes those children at greater neuropsychiatric risk. Insomnia was found to onset in early childhood, highlighting the potential for early intervention strategies for psychiatric risk informed by sleep profile.

T-type Ca2+ channels and inward rectifier K+ channels contribute to the orexin-induced facilitation of GABAergic transmission onto pyramidal neurons in the prefrontal cortex of juvenile mice

Orexin is a neuropeptide restrictedly synthesized in the hypothalamus, but extensively modulates the whole brain region activity including prefrontal cortex (PFC), and involved in the pathophysiology of psychiatric disorders. GABAergic interneurons in the mPFC are a promising pharmacological target for developing antidepressant therapies. Here, we examined the effects of the orexin on GABAergic transmission onto pyramidal neurons in the deep layers of the mPFC. We found that bath application of orexin dose-dependently increased the amplitude of evoked IPSCs (eIPSCs). Orexin increased the frequency but not the amplitude of miniature IPSCs (mIPSCs). Ca²⁺ influx through T-type voltage-gated Ca²⁺ channels is required for orexin-induced increases in GABA release. We also found orexin increases GABA release probability and the number of releasable vesicles. Orexin depolarizes somatostatin (Sst) interneurons without effects on the firing rate of action potentials (APs) of Sst interneurons. Orexin-induced depolarization of Sst interneurons is independent of extracellular Na⁺, Ca²⁺ and T-type Ca²⁺ channels, but requires inward rectifier K⁺ channels (Kirs). The present study suggests that orexin enhances GABAergic transmission onto mPFC pyramidal neurons through inhibiting Kirs on Sst interneurons, which further depolarizes interneurons leading to increase in Ca²⁺ influx via T-type Ca²⁺ channels. Our results may provide a cellular and molecular mechanism that helps explain the physiological functions of orexin in the brain.

Central Disorders of Hypersomnolence: Association with Fatigue, Depression and Sleep Inertia Prevailing in Women

Fatigue, depression, and sleep inertia are frequently underdiagnosed manifestations in narcolepsy and idiopathic hypersomnia. Our cross-sectional study design included diagnostic interview accompanied by assessment instruments and aimed to explore how these factors influence disease severity as well as to elucidate any sex predisposition. One hundred and forty-eight subjects (female 63%) were divided into narcolepsy type 1 (NT1; n = 87, female = 61%), narcolepsy type 2 (NT2; n = 22, female = 59%), and idiopathic hypersomnia (IH; n = 39, female = 69%). All subjects completed a set of questionnaires: Epworth Sleepiness Scale (ESS), Hospital Anxiety and Depression Scales (HADS), Fatigue Severity Scale (FSS), and Sleep Inertia Questionnaire (SIQ). In narcoleptic subjects, questionnaire data were correlated with the Narcolepsy Severity Scale (NSS), and in subjects with idiopathic hypersomnia, with the Idiopathic Hypersomnia Severity Scale (IHSS). The highest correlation in narcoleptic subjects was found between NSS and ESS (r = 0.658; p < 0.0001), as well as FSS (r = 0.506; p < 0.0001), while in subjects with idiopathic hypersomnia, the most prominent positive correlations were found between IHSS and SIQ (r = 0.894; p < 0.0001), FSS (r = 0.812; p < 0.0001), HADS depression scale (r = 0.649; p = 0.0005), and HADS anxiety scale (r = 0.528; p < 0.0001). ESS showed an analogic correlation with disease severity (r = 0.606; p < 0.0001). HADS anxiety and depression scores were higher in females (p < 0.05 and p < 0.01), with similar results for FSS and SIQ scales (p < 0.05 for both), and a trend toward higher ESS values in females (p = 0.057). Our study illustrates that more attention should be focused on pathophysiological mechanisms and associations of fatigue, depression, as well as sleep inertia in these diseases; they influence the course of both illnesses, particularly in women.

Effects of Sleep Deficiency on Risk, Course, and Treatment of Psychopathology

This article reviews the literature on the relationship between sleep deficiency and unipolar and bipolar depression, anxiety disorders, and posttraumatic stress disorder. We consider the evidence for sleep as a contributory causal factor in the development of psychiatric disorders, as well as sleep as an influential factor related to the outcome and recurrence of psychopathology. A case for sleep deficiency being an important treatment target when sleep and psychiatric disorders are comorbid is also made. Our recommendation is that sleep deficiency is recognized as a means to positively impact the development and course of psychopathology and, as such, is routinely assessed and treated in clinical practice.

50th anniversary of the ESRS in 2022-JSR special issue

This article addresses the clinical presentation, diagnosis, pathophysiology and management of narcolepsy type 1 and 2, with a focus on recent findings. A low level of hypocretin-1/orexin-A in the cerebrospinal fluid is sufficient to diagnose narcolepsy type 1, being a highly specific and sensitive biomarker, and the irreversible loss of hypocretin neurons is responsible for the main symptoms of the disease: sleepiness, cataplexy, sleep-related hallucinations and paralysis, and disrupted nocturnal sleep. The process responsible for the destruction of hypocretin neurons is highly suspected to be autoimmune, or dysimmune. Over the last two decades, remarkable progress has been made for the understanding of these mechanisms that were made possible with the development of new techniques. Conversely, narcolepsy type 2 is a less well-defined disorder, with a variable phenotype and evolution, and few reliable biomarkers discovered so far. There is a dearth of knowledge about this disorder, and its aetiology remains unclear and needs to be further explored. Treatment of narcolepsy is still nowadays only symptomatic, targeting sleepiness, cataplexy and disrupted nocturnal sleep. However, new psychostimulants have been recently developed, and the upcoming arrival of non-peptide hypocretin receptor-2 agonists should be a revolution in the management of this rare sleep disease, and maybe also for disorders beyond narcolepsy.

Association between hospital-diagnosed sleep disorders and suicide: a nationwide cohort study

STUDY OBJECTIVES

Sleep disorders are related to mental disorders. Yet few studies have examined their association with suicide. We examined whether males and females diagnosed with sleep disorders had higher rates of suicide than individuals not diagnosed with sleep disorders.

METHODS

In a cohort study, nationwide data on all males and females aged over 15 years living in Denmark during 1980-2016 were analyzed. Sleep disorders were identified through diagnoses recorded during contacts to somatic hospitals. Incidence rate ratios (IRR) were estimated using Poisson regression models and adjusted for covariates.

RESULTS

In all, 3 674 563 males and 3 688 164 females were included, of whom 82 223 (2.2%, mean age: 50.2 years, SD: 17.5) males and 40 003 (1.1%, mean age: 50.6 years, SD: 19.9) females had sleep disorder diagnoses. Compared with those with no sleep disorders, the adjusted IRR for suicide were 1.6 (95% CI, 1.4 to 1.7) and 2.2 (95% CI, 1.8 to 2.6) for males and females with sleep disorders, respectively. Excess rates for narcolepsy were found for males (IRR: 1.2, 95% CI, 1.0 to 1.5) and females (IRR: 3.3, 95% CI, 3.0 to 4.1), and for sleep apnea in males (IRR: 1.8, 95% CI, 1.5 to 2.2). A difference with respect to age and sex was observed (p < 0.001) between males and females. Males and females had IRR of 4.1 (95% CI, 3.1 to 5.5) and 7.0 (95% CI, 4.8 to 10.1), during the first 6 months after being diagnosed with a sleep disorder.

CONCLUSIONS

Sleep disorders were associated with higher suicide rates even after adjusting for preexisting mental disorders. Our findings suggest attention toward suicidality in patients with sleep disorders is warranted.

Does Insomnia Increase the Risk of Suicide in Hospitalized Patients with Major Depressive Disorder? A Nationwide Inpatient Analysis from 2006 to 2015

Introduction. Insomnia is an important symptom associated with major depressive disorder (MDD). In addition, it is one of the risk factors for suicide. Studies have shown the relationship be-tween insomnia and suicidal behavior in patients with MDD. However, this association has not been evaluated in a large sample of hospitalized patients. Objectives. To evaluate the suicidal be-havior in MDD patients with insomnia compared to those without insomnia. Methods. From the National Inpatient Sample (NIS 2006−2015) database using the ICD-9 code, patients’ data were obtained with the primary diagnosis of MDD and comorbid diagnosis of insomnia disorders (MDD+I). These patients were compared with MDD patients without insomnia disorders (MDD−I) by performing a 1:2 match for the primary diagnosis code. Suicidal ideation/attempt da-ta were compared between the groups by multivariate logistic regression analysis. Results. After the diagnostic code matching, 139061 patients were included in the MDD+I group and 276496 patients in the MDD−I group. MDD+I patients were older (47 years vs. 45 years, p < 0.001) com-pared to the MDD−I group. The rate of suicidal ideation/attempt was 56.0% in the MDD+I group and 42.0% in the MDD−I group (p < 0.001). After adjusting for age, sex, race, borderline personal-ity disorders, anxiety disorders, and substance use disorders, ‘insomnia’ was associated with 1.71 times higher odds of suicidal behavior among MDD patients admitted to the hospital. (Odds ratio: 1.71, 95% confidence interval 1.60−1.82, p < 0.001). Conclusions. Insomnia among MDD patients is significantly associated with the risk of suicide. MDD patients with insomnia need to be closely monitored for suicidal behavior.

Assessing the depression risk in the U.S. adults using nomogram

BACKGROUND

Depression has received a lot of attention as a common and serious illness. However, people are rarely aware of their current depression risk probabilities. We aimed to develop and validate a predictive model applicable to the risk of depression in US adults.

METHODS

This study was conducted using the database of the National Health and Nutrition Examination Survey (NHANES, 2017-2012). In particular, NHANES (2007-2010) was used as the training cohort (n = 6015) for prediction model construction and NHANES (2011-2012) was used as the validation cohort (n = 2812) to test the model. Depression was assessed (defined as a binary variable) by the Patient Health Questionnaire (PHQ-9). Socio-demographic characteristics, sleep time, illicit drug use and anxious days were assessed using a self-report questionnaire. Logistic regression analysis was used to evaluate independent risk factors for depression. The nomogram has the advantage of being able to visualize complex statistical prediction models as risk estimates of individualized disease probabilities. Then, we developed two depression risk nomograms based on the results of logistic regression. Finally, several validation methods were used to evaluate the prediction performance of nomograms.

RESULTS

The predictors of model 1 included gender, age, income, education, marital status, sleep time and illicit drug use, and model 2, furthermore, included anxious days. Both model 1 and model 2 showed good discrimination ability, with a bootstrap-corrected C index of 0.71 (95% CI, 0.69-0.73) and 0.85 (95% CI, 0.83-0.86), and an externally validated C index of 0.71 (95% CI, 0.68-0.74) and 0.83 (95% CI, 0.81-0.86), respectively, and had well-fitted calibration curves. The area under the receiver operating characteristic curve (AUC) values of the models with 1000 different weighted random sampling and depression scores of 10-17 threshold range were higher than 0.7 and 0.8, respectively. Calculated net reclassification improvement (NRI) and integrated discrimination improvement (IDI) showed the discrimination or accuracy of the prediction models. Decision curve analysis (DCA) demonstrated that the depression models were practically useful. The network calculators work for participants to make personalized predictions.

CONCLUSIONS

This study presents two prediction models of depression, which can effectively and accurately predict the probability of depression as well as helping the U.S. civilian non-institutionalized population to make optimal treatment decisions.

Self-reported symptoms and objective measures in idiopathic hypersomnia and hypersomnia associated with psychiatric disorders: a prospective cross-sectional study

STUDY OBJECTIVES

In some patients, it is difficult to correctly nosologically classify daytime sleepiness. Clinical manifestations may be nonspecific; on the basis of objective measures it is possible to determine the current severity of sleepiness, but they do not always allow accurate diagnosis. It is especially difficult to distinguish between idiopathic hypersomnia (IH) and hypersomnia associated with a psychiatric disorder (PSY).

METHODS

To find significant differences between the IH and PSY groups, we included 67 patients (IH, n = 15; PSY, n = 52) in the study, focusing on differences in self-reported symptoms, evaluating current depressive symptoms using the Beck Depression Inventory-II score and personality traits measured by the Temperament and Character Inventory. All of the patients underwent polysomnography, the Multiple Sleep Latency Test, and ad libitum sleep monitoring.

RESULTS

The patients with IH showed greater difficulty than those in the PSY group with waking up in the morning (P < .001) and complained of memory (P = .04) and attention deficit (P = .006). They also showed higher total sleep time (P < .001) and sleep efficiency (P = .007) and a shorter mean sleep latency on the Multiple Sleep Latency Test (P < .001). Nevertheless, the IH and PSY groups did not differ in Beck Depression Inventory scores or personality characteristics.

CONCLUSIONS

IH is a syndrome in which depression/external life stressors and personality characteristics also play a role. Patients with IH may benefit from the cooperation of sleep specialists with psychotherapists/psychiatrists.

CITATION

Bušková J, Novák T, Miletínová E, et al. Self-reported symptoms and objective measures in idiopathic hypersomnia and hypersomnia associated with psychiatric disorders: a prospective cross-sectional study. J Clin Sleep Med. 2022;18(3):713-720.

Hypocretin/Orexin Interactions with Norepinephrine Contribute to the Opiate Withdrawal Syndrome

We previously found that human heroin addicts and mice chronically exposed to morphine exhibit a significant increase in the number of detected hypocretin/orexin (Hcrt)-producing neurons. However, it remains unknown how this increase affects target areas of the hypocretin system involved in opioid withdrawal, including norepinephrine containing structures locus coeruleus (LC) and A1/A2 medullary regions. Using a combination of immunohistochemical, biochemical, imaging, and behavioral techniques, we now show that the increase in detected hypocretin cell number translates into a significant increase in hypocretin innervation and tyrosine hydroxylase (TH) levels in the LC without affecting norepinephrine-containing neuronal cell number. We show that the increase in TH is completely dependent on Hcrt innervation. The A1/A2 regions were unaffected by morphine treatment. Manipulation of the Hcrt system may affect opioid addiction and withdrawal.SIGNIFICANCE STATEMENT Previously, we have shown that the hypothalamic hypocretin system undergoes profound anatomic changes in human heroin addicts and in mice exposed to morphine, suggesting a role of this system in the development of addictive behaviors. The locus coeruleus plays a key role in opioid addiction. Here we report that the hypothalamic hypocretin innervation of the locus coeruleus increases dramatically with morphine administration to mice. This increase is correlated with a massive increase in tyrosine hydroxylase expression in locus coeruleus. Elimination of hypocretin neurons prevents the tyrosine hydroxylase increase in locus coeruleus and dampens the somatic and affective components of opioid withdrawal.

Idiopathic Hypersomnia and Depression, the Challenge for Clinicians and Researchers

The review deals with idiopathic hypersomnia, focusing mostly on the research findings about the presence, onset and severity of excessive daytime sleepiness and depressive symptoms in patients with idiopathic hypersomnia.

Narcolepsy: A clinical review

ABSTRACT

Narcolepsy continues to be a significantly underdiagnosed/misdiagnosed condition worldwide. According to the National Institutes of Health (NIH), an estimated 135,000 to 200,000 patients in the United States are living with narcolepsy. However, due to the number of patients who either do not seek medical advice for their symptoms or receive an incorrect initial diagnosis at onset, this number may be higher. This article reviews the different subtypes of narcolepsy along with the pathophysiology, screening guidelines, clinical features, diagnosis, and management of the disorder. Educational awareness from a healthcare and patient standpoint can enhance early detection and accurate diagnosis of narcolepsy and improve patient quality of life.

2018 worldwide survey of health-care providers caring for patients with narcolepsy: WSS narcolepsy task force

BACKGROUND

There are limited data available on regional differences in the diagnosis and management of narcolepsy. In order to better understand worldwide trends in clinical assessment and management of narcolepsy, a survey of health-care providers was conducted by the World Sleep Society Narcolepsy task force.

METHODS

A total of 146 surveys that included items on the diagnosis and management of narcolepsy were completed by practitioners representing 37 countries.

RESULTS

Most of the participants were from Europe, North America, Oceania, Asia and Latin America. A consistent approach to applying the diagnostic criteria of Narcolepsy was documented with the exception of measurement of CSF hypocretin-1, which has limited availability. While the majority of practitioners (58%) reported not using the test, 1% indicated always evaluating CSF hypocretin-1 levels. There was much variability in the availability of currently recommended medications such as sodium oxybate and pitolisant; modafinil and antidepressants were the most commonly used medications. Amphetamines were unavailable in some countries.

CONCLUSION

The results of the study highlight clinical and therapeutic realities confronted by worldwide physicians in the management of narcolepsy. While the diagnostic criteria of narcolepsy rely in part on the quantification of CSF hypocretin-1, few physicians reported having incorporated this test into their routine assessment of the condition. Regional differences in the management of narcolepsy appeared to be related to geographic availability and expense of the therapeutic agents.

Excessive sleepiness in patients with psychosis: An initial investigation

Clinical experience indicates that excessive sleepiness and hypersomnia may be a common issue for patients with psychosis. Excessive sleepiness is typically ascribed to the sedating effects of antipsychotic medications but there may be other potential contributors such as sleep disorders and depression. Furthermore, the impact of excessive sleepiness itself on patients' symptoms and general wellbeing is yet to be examined. The current study reports an exploratory cross-sectional between-groups comparison of patients with early psychosis fulfilling criteria assessed in a diagnostic interview for problematic excessive sleepiness (n = 14), compared with those not reporting excessive sleepiness (n = 46). There were no differences between the groups in diagnosis, medication type, or antipsychotic medication dosage. There were no significant group differences in sleep duration. Significantly lower activity levels were found in the excessive sleepiness group. Insomnia and nightmares were common in those reporting excessive sleepiness. No significant differences were found in psychiatric symptoms, although data did indicate more severe cognitive disorganisation and grandiosity, but less severe paranoia and hallucinations, in the excessive sleepiness group. Wide confidence intervals and small sample size mean that care should be taken interpreting these results. Overall, this study indicates that excessive sleepiness may not be solely related to medication but also to low levels of activity and other sleep disorders. This is a novel finding that, if replicated, could indicate routes of intervention for this clinical issue. Future research should aim to disentangle directions of effect amongst sleepiness, mood, activity, and psychotic symptoms and investigate possible interventions for excessive sleepiness in psychosis.

Multiple sleep latency test and polysomnography in patients with central disorders of hypersomnolence

A multiple sleep latency test (MSLT) with occurrence of sleep onset REM periods (SOREMP) is considered one of the central diagnostic criteria for narcolepsy according to the International Classification of Sleep Disorders, but its sensitivity and specificity have been questioned. This study aims to describe MSLT and polysomnography (PSG) findings, including frequency and distribution of SOREMP during the day, in a large cohort of patients with central disorders of hypersomnolence (CDH). We retrospectively analyzed electrophysiological data from MSLT and PSG in 370 consecutive patients with narcolepsy type 1 (NT1, n = 97), type 2 (NT2, n = 31), idiopathic hypersomnia (IH, n = 48), nonorganic hypersomnia (NOH, n = 116) and insufficient sleep syndrome (ISS, n = 78). NT1 and NT2 patients had a significantly shorter mean Sleep Latency (mSL) and REM-Latency (REML) in MSLT and PSG. SOREMP occurred more frequently in narcoleptic vs. non-narcoleptic patients in MSLT and PSG. Occurrence of 3 or more SOREMP in MSLT and a SOREMP in PSG had a very high specificity and positive predictive value (98%/96% and 100% respectively), however relatively low sensitivity (65% and 45% respectively). NT1 more than NT2 patients have shorter mSL and more frequent SOREMP in MSLT and shorter SL as well as REML during nocturnal PSG. Increasing numbers of SOREMP in MSLT and especially SOREMP during PSG increase specificity on the expense of sensitivity in diagnosing narcolepsy. Therefore, frequency of SOREMP in MSLT naps and PSG can help to discriminate but not clearly separate narcoleptic from non-narcoleptic patients.

Pleasure, addiction, and hypocretin (orexin)

The hypocretins/orexins were discovered in 1998. Within 2 years, this led to the discovery of the cause of human narcolepsy, a 90% loss of hypothalamic neurons containing these peptides. Further work demonstrated that these neurons were not simply linked to waking. Rather these neurons were active during pleasurable behaviors in waking and were silenced by aversive stimulation. This was seen in wild-type mice, rats, cats, and dogs. It was also evident in humans, with increased Hcrt release during pleasurable activities and decreased release, to the levels seen in sleep, during pain. We found that human heroin addicts have, on average, an increase of 54% in the number of detectable Hcrt neurons compared to "control" human brains and that these Hcrt neurons are substantially smaller than those in control brains. We found that in mice, chronic morphine administration induced the same changes in Hcrt neuron number and size. Our studies in the mouse allowed us to determine the specificity, dose response relations, time course of the change in the number of Hcrt neurons, and that the increased number of Hcrt neurons after opiates was not due to neurogenesis. Furthermore, we found that it took a month or longer for these anatomical changes in the mouse brain to return to baseline. Human narcoleptics, despite their prescribed use of several commonly addictive drugs, do not show significant evidence of dose escalation or substance use disorder. Similarly, mice in which the peptide has been eliminated are resistant to addiction. These findings are consistent with the concept that an increased number of Hcrt neurons may underlie and maintain opioid or cocaine use disorders.

Depression and suicidal thoughts in untreated and treated narcolepsy: Systematic analysis

OBJECTIVES

To assess the frequency and determinants of depressive symptoms and suicidal thoughts in adults with narcolepsy type 1 (NT1) and controls, as well as the changes after NT1 management and the risk factors of major depressive episode (MDE) and suicide risk (SR) in NT1.

METHODS

Two hundred ninety-seven patients with NT1 (age 39 ± 17 years, 172 drug-free) and 346 controls (age 38 ± 16 years) underwent a comprehensive clinical evaluation including the Beck Depression Inventory-II (BDI-II) self-questionnaire, with 1 item on suicidal thoughts. One hundred one drug-free patients with NT1 completed the BDI-II a second time during treatment. In 162 patients with NT1, the face-to-face Mini International Neuropsychiatric Interview was performed to formally diagnose current MDE and SR.

RESULTS

BDI-II total scores were higher in patients with NT1 than controls and in untreated than treated patients. Patients with moderate to severe BDI-II scores (24.9%) were less educated, were more frequently obese, and had more severe narcolepsy symptoms, more autonomic dysfunctions, and poorer quality of life. Results were unchanged in models adjusted for NT1 medication intake. Suicidal thoughts were more frequent in untreated patients than controls (22.7% vs 12.4%). Patients with suicidal thoughts were more likely to be men and to have more severe narcolepsy symptoms. After narcolepsy management, BDI-II total score and suicidal thoughts decreased. MDE was diagnosed in 29 (18.1%) and SR in 27 (16.9%) patients.

CONCLUSIONS

Depression, depressive symptoms, suicidal thoughts, and SR were frequent in patients with NT1, especially those without treatment, and were associated with NT1 severity. Depressive symptoms and suicidal thoughts improved after NT1 management.

Excessive daytime sleepiness in cancer patients

PURPOSE

Excessive daytime sleepiness (EDS) is commonly reported in patients with cancer, and it is also a cardinal feature of central disorders of hypersomnolence. Multiple sleep latency testing (MSLT) is used for objective assessment.

METHODS

A retrospective review of patients with cancer history who underwent formal sleep evaluation and MSLT from 2006 to 2019 was performed. Clinical characteristics, sleep-related history, and polysomnographic data were reviewed.

RESULTS

Of 16 patients with cancer history, 9 were women (56%) and median age was 49. Cancer diagnoses included 4 central nervous system, 3 breast, 1 lymphoma, and 9 other solid malignancies, and 31% were undergoing active treatment. Comorbid conditions included depression, obstructive sleep apnea, and cancer-related fatigue. Daytime fatigue (94%), daily naps (81%), and EDS (69%) were the most common symptoms. Hypnopompic and hypnogogic hallucinations, sleep paralysis, sleep attacks, and cataplexy were present in a few. Epworth Sleepiness Scale scores were consistent with EDS in 88%, and mean sleep latency was less than 8 min in 69%. Only 31% had more than 2 sleep-onset REM periods. MSLT supported diagnoses of central disorders of hypersomnolence in 5 patients (4 narcolepsy, 1 idiopathic hypersomnia); 5 hypersomnia due to a medical disorder, psychiatric condition, or medication; and 6 with normal results. Pharmacotherapy was prescribed in 5 patients.

CONCLUSIONS

EDS in patients with cancer may be multifactorial, but persistent symptoms may indicate an underlying disorder of hypersomnolence. Sleep referral and polysomnography to exclude other sleep disorders may be indicated. MSLT can help confirm the diagnosis. In those with normal MSLT, further evaluation for mood disorder should be considered.

Patterns and correlates of sleep duration in the Southern cohort community study

OBJECTIVE

To investigate whether race (African American (AA) and white) is associated with sleep duration among adults from low socioeconomic (SES) strata and whether SES status, lifestyle behaviors, or health conditions are associated with sleep duration within race-sex groups.

METHODS

This cross-sectional study includes 78,549 participants from the Southern Community Cohort Study (SCCS). Averaged daily sleep duration was assessed by weighted averages of self-reported sleep duration on weekdays and weekends. Adjusted odds ratios (ORs) of very short (<5 h/day), short (5-6 h/day), and long sleep (≥9 h/day) associated with pre-selected risk factors in each race-sex group were determined by multinomial logistic models.

RESULTS

The prevalence of very short and short sleep was similar among AAs (6.2% and 29.1%) and whites (6.5% and 29.1%). Long sleep was considerably more prevalent among AAs (19.3%) than whites (13.0%). Very short sleep was associated with lower education and family income, with stronger associations among whites. Higher physical activity levels significantly decreased odds for both very short (OR = 0.80) and long sleep (OR = 0.78). Smoking, alcohol use, and dietary intake were not associated with sleep duration. Regardless of race or sex, very short, short, and long sleep were significantly associated with self-reported health conditions, especially depression (ORs were 2.06, 1.33, and 1.38, respectively).

CONCLUSIONS

Sleep duration patterns differed between AAs and whites from the underrepresented SCCS population with low SES. Sleep duration was associated with several socioeconomic, health behaviors, and health conditions depending on race and sex.

Clarifying the role of sleep in depression: A narrative review

It has been established that 4.4 to 20% of the general population suffers from a major depressive disorder (MDD), which is frequently associated with a dysregulation of normal sleep-wake mechanisms. Disturbances of circadian rhythms are a cardinal feature of psychiatric dysfunctions, including MDD, which tends to indicate that biological clocks may play a role in their pathophysiology. Thus, episodes of depression and mania or hypomania can arise as a consequence of the disruption of zeitgebers (time cues). In addition, the habit of sleeping at a time that is out of phase with the body's other biological rhythms is a common finding in depressed patients. In this review, we have covered a vast area, emerging from human and animal studies, which supports the link between sleep and depression. In doing so, this paper covers a broad range of distinct mechanisms that may underlie the link between sleep and depression. This review further highlights the mechanisms that may underlie such link (e.g. circadian rhythm alterations, melatonin, and neuroinflammatory dysregulation), as well as evidence for a link between sleep and depression (e.g. objective findings of sleep during depressive episodes, effects of pharmacotherapy, chronotherapy, comorbidity of obstructive sleep apnea and depression), are presented.

Association between habitual weekday sleep duration and depressive symptoms among Chinese adolescents:The role of mode of birth delivery

BACKGROUND

Depressive symptoms among adolescents are common. This study aimed to assess, among Chinese adolescents, the associations of habitual weekday sleep duration with depressive symptoms and whether these associations varied with the mode of birth delivery.

METHODS

Data were from the 2015 School-based Chinese Adolescents Health Survey, and 150,053 students' questionnaires were qualified for analysis. Multi-level logistic regression models were performed.

RESULTS

A weekday sleep duration of ≤5 h/night was associated with depressive symptoms (adjusted odds ratio [aOR]=2.98, 95% CI=2.75-3.24), and adolescents who reported a weekday sleep duration of 5-7 h/night (aOR=1.69, 95% CI=1.60-1.79) and >9 h/night (aOR=1.28, 95% CI=1.11-1.45) were also at a higher risk of depressive symptoms. Stratification analyses showed that in both adolescents delivered by vaginal birth and cesarean section (CS), a weekday sleep duration of ≤5 h/night, 5-7 h/night, and >9 h/night were associated with the increased risk of depressive symptoms in the adjusted models, and the magnitudes of the aORs in adolescents delivered by CS were slightly higher than those in adolescents delivered by vaginal birth.

LIMITATIONS

The cross-sectional study design and self-reported sleep duration and depressive symptoms.

CONCLUSION

This study demonstrates a significant U-shaped association between weekday sleep duration and depressive symptoms among Chinese adolescents. In both adolescents delivered by vaginal birth and CS, those who reported having abnormal sleep duration were at a high risk of depressive symptoms. Based on the findings of this study, we suggest sleep duration and mode of delivery should be a matter of concern for public health authorities.

Reverse translation of major depressive disorder symptoms: A framework for the behavioural phenotyping of putative biomarkers

BACKGROUND

Reverse translating putative biomarkers of depression from patients to animals is complex because Major Depressive Disorder (MDD) is a highly heterogenous condition. This review proposes an approach to reverse translation based on relating relevant bio-behavioural functions in laboratory rodents to MDD symptoms.

METHODS

This systematic review outlines symptom clusters assessed by psychometric tests of MDD and antidepressant treatment response including the Montgomery-Åsberg Depression Rating Scale, the Hamilton Depression Rating Scale, and the Beck Depression Inventory. Symptoms were related to relevant behavioural assays in laboratory rodents.

RESULTS

The resulting battery of tests includes passive coping, anxiety-like behaviours, sleep, caloric intake, cognition, psychomotor functions, hedonic reactivity and aversive learning. These assays are discussed alongside relevant clinical symptoms of MDD, providing a framework through which reverse translation of a biomarker can be interpreted.

LIMITATIONS

Certain aspects of MDD may not be quantified by tests in laboratory rodents, and their biological significance may not always be of clinical relevance.

CONCLUSIONS

Using this reverse translation approach, it is possible to clarify the functional significance of a putative biomarker in rodents and hence translate its contribution to specific clinical symptoms, or clusters of symptoms.

Association of Inattention, Hyperactivity, and Hypersomnolence in Two Clinic-Based Adult Cohorts

Objective: To assess the relationship between excessive daytime sleepiness (EDS), inattention, and hyperactivity/impulsivity in adults with ADHD and central hypersomnia. Method: Drug-free adult patients with ADHD (n = 100) or hypersomnia (n = 100) were evaluated using a structured clinical interview and self-report questionnaires on ADHD symptoms and EDS. Results: In all, 61% of patients with hypersomnia had clinically significant ADHD symptoms with 25% having an ADHD diagnosis (with both childhood and adulthood ADHD symptoms) and 36% ADHD-like symptoms, without history of childhood ADHD. EDS was reported in 47% of patients with ADHD, among whom 22% had a hypersomnolence disorder. Conclusion: We confirmed the high frequency of ADHD and ADHD-like symptoms in central hypersomnia, and of EDS and hypersomnolence in ADHD in adults. The nature of the link between EDS, inattention, and hyperactivity appears to be complex that may involve either a cause-effect relationship or intrinsic features of a similar neurodevelopmental dysfunction.

Somatic symptoms are associated with Insomnia disorder but not Obstructive Sleep Apnoea or Hypersomnolence in traumatic brain injury

BACKGROUND

Previous studies examining insomnia in populations with traumatic brain injury (TBI) have not distinguished between transient insomnia symptoms and insomnia disorder and associations have been confounded by other highly prevalent sleep disorders post-TBI.

OBJECTIVE

To investigate the associations between affective symptoms and somatoform symptoms in patients with TBI and insomnia, sleep apnoea and hypersomnolence.

METHODS

Twenty-four participants from a multidisciplinary brain injury rehabilitation service with TBI were assessed for insomnia disorder, using Diagnostic and Statistical Manual Fifth Edition (DSM-5) criteria. Associations with affective and somatic symptoms were assessed, using the DASS-21 and PHQ-15 respectively. The same cohort was divided for Obstructive Sleep Apnoea (OSA) and hypersomnolence and analysed for the same outcomes. Associations were assessed using Pearson's correlation and a logistic binary regression model was developed to predict insomnia in patients with brain injury.

RESULTS

The insomnia disorder group (n = 11) had significantly higher rates somatoform symptoms (p < 0.05), compared to those without insomnia disorder (n = 13). These factors were not significantly associated with OSA or hypersomnolence. Pain was significantly associated with insomnia disorder.

CONCLUSIONS

Insomnia disorder, not OSA or hypersomnolence, may be related to the presence of somatoform symptoms in people with TBI. Addressing insomnia disorder may potentially improve recovery.

Therapeutic Approaches for the Management of Sleep Disorders in Geriatric Population

OBJECTIVE

Aging is a natural biological phenomenon that occurs in human beings. With increasing of age, there is an appearance of deleterious changes related to progression onto pathological conditions, including hypertension, heart disease, diabetes, hearing and vision impairments, as well as sleep disorders. It is important to recognize that some sleep disturbances reported by aged subjects include insomnia, obstructive sleep apnea, restless legs syndrome, among others. Moreover, accumulating evidence indicates that coexistence of medical issues with sleep disorders constitutes clinical challenges for treatment of comorbidities in elderly. Here, we have attempted to review and summarize the available literature that assesses the sleep disturbances in aging. In addition, we highlight the management of sleep disorders associated with aging. Due to the particular health condition of aged adults, the development of effective pharmacological interventions for sleep disorders treatment in aging is warranted.

METHODS

Review of studies retrieved from the PubMed.

RESULTS

The sleep-wake cycle includes abnormalities classified as sleep disorders. Comorbidity between sleep disturbances and aging-related health issues will represent a public health challenge to be addressed in the near future. Moreover, this scenario will suggest an area that requires further drug investigation and design of new pharmacological and pharmaceutical strategies to treat sleep disorders in the elderly population.

CONCLUSION

The review highlights the sleep disturbances in aging. We focus on current knowledge in medicinal chemistry and further design of new treatments tools for managing sleep disturbances in the aged population.

Sleep in seasonal affective disorder

Sleep in seasonal affective disorder (SAD) has been primarily characterized by delayed sleep timing and self-reports of hypersomnolence. It is unclear whether delayed sleep timing is due to circadian or behavioral misalignment and if effective treatments operate independently of the circadian system. Discrepancies between self-report and actigraphic/polysomnographic sleep duration in SAD hinder clarification of hypersomnolence as a cardinal symptom. Previous studies have largely neglected the summer remission period in SAD, which could yield valuable insight to the role sleep disturbances play in the onset and recurrence of winter depressive episodes. Future studies should incorporate multi-method, multi-season assessment of sleep and circadian rhythms to best characterize relevant sleep-circadian phenotypes. Empirically determining sleep phenotypes present in SAD will pave the way for targeted sleep interventions.

Clinical neurophysiology of CNS hypersomnias

Central nervous system hypersomnias (narcolepsy type 1 and type 2, idiopathic hypersomnia, and Kleine-Levin syndrome) are orphan sleep disorders in which the predominant symptom is excessive daytime sleepiness. The evaluation of sleepiness requires rigorous clinical and neurophysiologic approaches that may include the Epworth Sleepiness Scale, multiple sleep latency tests, and the maintenance of wakefulness test. However, to date, no gold standard measurement of excessive sleepiness exists, and there are no quantifiable biologic markers. The main pathophysiologic feature of central hypersomnias is thought to reflect a deficiency of arousal systems, rather than an overactivity of sleep systems or an imbalance between those systems. Impaired neurotransmission of hypocretin/orexin (neuropeptides of the lateral hypothalamus) is involved in the neurobiology of narcolepsy with cataplexy (NT1). NT1 is a well-characterized disorder, due to the destruction of hypocretin/orexin neurons by a probable autoimmune process. The biologic hallmarks of the other central hypersomnias remain unknown, and neurophysiologic biomarkers are still of major importance for the diagnosis and characterization of those disorders.

Identifying subtypes of Hypersomnolence Disorder: a clustering analysis

BACKGROUND

Patient heterogeneity is problematic for the accurate assessment and effective treatment of Hypersomnolence Disorder. Clustering analysis is a preferred approach for establishing homogenous subclassifications. Thus, this investigation aimed to identify more homogeneous subclassifications of Hypersomnolence Disorder through clustering analysis.

METHODS

Patients undergoing polysomnography (PSG) and multiple sleep latency test (MSLT) assessment for hypersomnolence were recruited as part of a larger investigation. A sample of patients with Hypersomnolence Disorder was determined based on a post hoc chart review protocol. After removing persons with missing data, 62 participants were included in the analyses. Self-report total sleep time, Epworth Sleepiness Scale (ESS) score, and Sleep Inertia Questionnaire (SIQ) score were chosen as clustering variables to mirror Hypersomnolence Disorder diagnostic traits. A statistically-driven clustering process produced two clusters using Ward's D hierarchical approach. Clusters were compared across characteristics, self-report measures, PSG/MSLT results, and additional objective measures.

RESULTS

The resulting clusters differed across a variety of hypersomnolence-related subjective metrics and objective measurements. A more severe hypersomnolence phenotype was identified in a cluster that also had elevated depressive symptoms. This cluster endorsed significantly greater daytime sleepiness, sleep inertia, and functional impairment, while displaying longer sleep duration and worse vigilance.

CONCLUSIONS

These results provide growing support for a nosological reformulation of hypersomnolence associated with psychiatric disorders. Future research is necessary to solidify the conceptualization and characterization of unexplained hypersomnolence presenting with-and-without psychiatric illness.

Optimizing Actigraphic Estimation of Sleep Duration in Suspected Idiopathic Hypersomnia

STUDY OBJECTIVES

To determine the optimal Actiwatch 2 setting configuration for the estimation of total sleep time (TST) in persons with suspected idiopathic hypersomnia.

METHODS

Thirty-three patients with a diagnosis of idiopathic hypersomnia (28 female; mean age = 33.7 ± 10.5) underwent ad libitum polysomnography with concurrent use of the Actiwatch 2. Actiwatch 2 sleep-wake activity threshold (SWAT; Low, Medium, and High) and sleep immobility onset and offset (SIOO; 5, 10, 15, 20, 25, and 30 epoch) duration were modified during data processing. The resultant 18 unique setting combinations were subsequently evaluated using Bland-Altman and epoch comparison analyses to determine optimal settings relative to polysomnography.

RESULTS

Low SWAT + 25 Epoch SIOO displayed the least divergence from polysomnography (mean difference 3.4 minutes). Higher SWAT and lower SIOO increased sensitivity and accuracy, but at the expense of reducing specificity and the ability to accurately estimate TST.

CONCLUSIONS

These results demonstrate that actigraphic settings should be carefully considered when estimating sleep duration. The Low + 25 Epoch configuration is indicated as most optimal for estimating TST in persons with suspected idiopathic hypersomnia.

COMMENTARY

A commentary on this article appears in this issue on page 539.

A systematic review on sleep alterations anticipating the onset of bipolar disorder

Background:

Sleep alterations are frequent occurrence in Bipolar Disorder (BD), both in acute and interepisodic phases. Sleep alterations have been also described both long before BD onset, as aspecific risk syndromes, or as immediate prodromes of BD onset. The aim of the present study is to systematically review the relationship between sleep alterations anticipating for the full-blown onset of BD, both in general and according to specific polarities of onset.

Methods:

A systematic literature research according to PRISMA statement and considering: 1. prospective studies about BD patients’ offspring with sleep alterations who later developed BD. 2. prospective studies assessing patients with sleep disorders who later developed BD. 3. retrospective studies on BD patients where sleep alterations before BD onset of the disease were reported.

Results:

A total of 16 studies were included in this review. Sleep disturbances may frequently appear 1 year before the onset of BD or more, often during childhood or adolescence. A decreased need for sleep may precede the onset of the illness, specially a manic episode, while insomnia appears to anticipate either a manic or a depressive episode. Hypersomnia seems to precede bipolar depressive episodes.

Conclusions:

Sleep alterations frequently appear long before the onset of BD, and appear to be related specifically to the polarity of the index episode. The detection and treatment of sleep alterations in special high risk populations may help achieving an earlier detection of the illness.

Orexin prevents depressive-like behavior by promoting stress resilience

Hypothalamic neuropeptide orexin has been implicated in the pathophysiology of psychiatric disorders and accumulating clinical evidence indicates a potential link between orexin and depression. However, the exact role of orexin in depression, particularly the underlying neural substrates and mechanisms, remains unknown. In this study, we reveal a direct projection from the hypothalamic orexinergic neurons to the ventral pallidum (VP), a structure that receives an increasing attention for its critical position in rewarding processing, stress responses, and depression. We find that orexin directly excites GABAergic VP neurons and prevents depressive-like behaviors in rats. Two orexin receptors, OX1R and OX2R, and their downstream Na+-Ca2+ exchanger and L-type Ca2+ channel co-mediate the effect of orexin. Furthermore, pharmacological blockade or genetic knockdown of orexin receptors in VP increases depressive-like behaviors in forced swim test and sucrose preference test. Intriguingly, blockage of orexinergic inputs in VP has no impact on social proximity in social interaction test between novel partners, but remarkably strengthens social avoidance under an acute psychosocial stress triggered by social rank. Notably, a significantly increased orexin level in VP is accompanied by an increase in serum corticosterone in animals exposed to acute stresses, including forced swimming, food/water deprivation and social rank stress, rather than non-stress situations. These results suggest that endogenous orexinergic modulation on VP is especially critical for protecting against depressive reactions to stressful events. The findings define an indispensable role for the central orexinergic system in preventing depression by promoting stress resilience.

Prevalence and risk factors of excessive daytime sleepiness in major depression: A study with 703 individuals referred for polysomnography

BACKGROUND

To date, few studies have investigated the prevalence and risk factors of excessive daytime sleepiness (EDS) in major depression. Thus, the aim of the present study was to examine the prevalence and risk factors of EDS in a large sample of individuals with major depression.

METHODS

Data from 703 individuals with major depression were retrospectively collected from the sleep laboratory research database of Erasme Hospital for analysis. A score of > 10 on the Epworth Sleepiness Scale was used as the cut-off for EDS. Logistic regression analyses were conducted to examine the clinical and demographic risk factors of EDS in major depression.

RESULTS

The prevalence of EDS in our sample was 50.8%. Multivariate logistic regression analysis revealed that the following were significant risk factors of EDS in major depression: non-use of short to intermediate half-life benzodiazepine receptor agonists, BMI ≥ 25 kg/m², age < 60 years, C-reactive protein > 7 mg/L, Beck Depression Inventory score ≥ 16, atypical depression, apnea-hypopnea index ≥ 15/h, and use of selective serotonin reuptake inhibitors or serotonin-norepinephrine reuptake inhibitors.

LIMITATIONS

To evaluate EDS, we used the Epworth Sleepiness Scale, which only allows for a subjective measure of daytime sleepiness.

CONCLUSION

EDS is a common symptom in individuals with major depression. In this subpopulation, interventions are possible for most risk factors of EDS, which justifies improved management of this symptom to avoid its negative consequences.

Narcolepsy and Other Central Hypersomnias

PURPOSE OF REVIEW

This article focuses on the clinical presentation, pathophysiology, diagnosis, differential diagnosis, and management of narcolepsy type 1 and narcolepsy type 2, idiopathic hypersomnia, Kleine-Levin syndrome, and other central disorders of hypersomnolence, as defined in the International Classification of Sleep Disorders, Third Edition (ICSD-3).

RECENT FINDINGS

In ICSD-3, the names of some central disorders of hypersomnolence have been changed: narcolepsy with cataplexy and narcolepsy without cataplexy have been renamed narcolepsy type 1 and narcolepsy type 2, respectively. A low level of hypocretin-1/orexin-A in the CSF is now theoretically sufficient to diagnose narcolepsy type 1, as it is a highly specific and sensitive biomarker. Conversely, other central hypersomnias are less well-defined disorders with variability in the phenotype, and few reliable biomarkers have been discovered so far. The epidemiologic observation that influenza A (H1N1) infection and vaccination are potential triggering factors of narcolepsy type 1 (discovered during the 2009 H1N1 pandemic) has increased interest in this rare disease, and progress is being made to better understand the process (highly suspected to be autoimmune) responsible for the destruction of hypocretin neurons. Treatment of narcolepsy remains largely symptomatic, usually initially with modafinil or armodafinil or with higher-potency stimulants such as methylphenidate or amphetamines. Several newer wake-promoting agents and psychostimulants have also been developed, including sodium oxybate, which has a role in the treatment of cataplexy and as an adjunctive wake-promoting agent, and pitolisant, a selective histamine H3 receptor inverse agonist that is currently only available in Europe.

SUMMARY

Although far less common than many other sleep disorders, central hypersomnias are among the most severe and disabling diseases in the field of sleep medicine, and their early recognition is of major importance for patients, especially children, to maximize their quality of life and functioning in activities of daily living.

Opiates increase the number of hypocretin-producing cells in human and mouse brain and reverse cataplexy in a mouse model of narcolepsy

The changes in brain function that perpetuate opiate addiction are unclear. In our studies of human narcolepsy, a disease caused by loss of immunohistochemically detected hypocretin (orexin) neurons, we encountered a control brain (from an apparently neurologically normal individual) with 50% more hypocretin neurons than other control human brains that we had studied. We discovered that this individual was a heroin addict. Studying five postmortem brains from heroin addicts, we report that the brain tissue had, on average, 54% more immunohistochemically detected neurons producing hypocretin than did control brains from neurologically normal subjects. Similar increases in hypocretin-producing cells could be induced in wild-type mice by long-term (but not short-term) administration of morphine. The increased number of detected hypocretin neurons was not due to neurogenesis and outlasted morphine administration by several weeks. The number of neurons containing melanin-concentrating hormone, which are in the same hypothalamic region as hypocretin-producing cells, did not change in response to morphine administration. Morphine administration restored the population of detected hypocretin cells to normal numbers in transgenic mice in which these neurons had been partially depleted. Morphine administration also decreased cataplexy in mice made narcoleptic by the depletion of hypocretin neurons. These findings suggest that opiate agonists may have a role in the treatment of narcolepsy, a disorder caused by hypocretin neuron loss, and that increased numbers of hypocretin-producing cells may play a role in maintaining opiate addiction.