The status of sleep abnormalities as a diagnostic test for major depressive disorder

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

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

Sex differences in insomnia and hypersomnia complaints during major depressive episode: Results from a national sample

BACKGROUND

Sex differences in sleep disturbances during major depressive episodes (MDE) have been suggested. This study compares the prevalence, sociodemographic characteristics, and psychiatric comorbidity associated with sleep complaints specific to each sex among adults with MDE. These findings are crucial for precise diagnosis, personalized treatment, and improved clinical outcomes.

METHODS

In a large nationally representative prospective survey, we used multi-adjusted logistic regression models including sociodemographic characteristics, psychiatric comorbidity, and depression severity to examine whether associations differ between men and women.

RESULTS

Among women, 93.3 % reported at least one type of sleep complaints (i.e., trouble falling asleep, early morning awakening or hypersomnia) while 91.0 % of men did, with respectively 78.3 % and 77.2 % of insomnia complaints, and 46.2 % and 41.3 % of hypersomnia complaints. Women with sleep complaints were more likely to be black, with lower individual incomes, have histrionic personality disorder or a specific phobia. Conversely, men with sleep complaints were more likely to have a lifetime diagnosis of mania spectrum disorder, generalized anxiety disorder, drug use disorder, as well as dependent and schizotypal personality disorders. Surprisingly, being "never married" has emerged as a protective factor against sleep complaints in women, while posing as a risk factor in men compared to other marital statuses. Differences and specificities were also noted concerning subtypes of insomnia and hypersomnia complaints.

LIMITATIONS

The cross-sectional design means the associations found do not imply causality.

CONCLUSIONS

These findings provide insights into the complex relationship between sleep and depression in men and women, highlighting the need for personalized interventions.

Association between sleep disorder and depression in stroke in the National Health and Nutrition Examination Surveys (NHANES) 2005 to 2014

BACKGROUND

To investigate the association between sleep disorder and depression in stroke population using data from the National Health and Nutrition Examination Surveys (NHANES) conducted between 2005 and 2014.

METHODS

Participants included stroke population who reported on sleep disorder and completed the Patient Health Questionnaire-9 (PHQ-9) to assess depressive symptom. Sleep disorder was self-reported and categorized dichotomously. Multivariate logistic regression, subgroup analysis, receiver operating characteristic curve (ROC) and restricted cubic spline (RCS) were used to explore the association between sleep disorder and depression.

RESULTS

The final sample included 566 stroke survivors (weighted n = 3,326,625). Multivariate logistic regression analysis confirmed that sleep disorder was independently associated with an increased risk of depression even after adjusting for potential confounders (OR = 2.616, 95 % CI: 2.561 to 2.599, P < 0.0001). Subgroup analysis indicated that this association was particularly strong among female stroke population (OR = 5.515). Sleep disorder as a significant predictor of depression, while the relationship between sleep time and depression is characterized by non-linearity.

CONCLUSIONS

Sleep disorder is significantly associated with an increased risk of depression in stroke. This relationship remains robust across various sociodemographic and lifestyle factors, highlighting the need for integrated interventions targeting both sleep and mood disturbances in stroke care.

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

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

Association Between EEG Power During Sleep and Attention Levels in Patients with Major Depressive Disorder

Purpose

Major depressive disorder (MDD) is associated with cognitive impairment through unclear mechanisms. We examined the relationship between sleep electroencephalogram (EEG) power and attention level in MDD.

Patients and Methods

Forty-seven untreated patients with MDD and forty-seven age- and sex-matched controls were included. We examined relative EEG power during non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep by fast Fourier transform. The Attention Network Test (ANT) was performed to evaluate attention levels.

Results

Compared to controls, patients with MDD had lower theta power during NREM (P = 0.018) and REM (P = 0.002) sleep, while higher beta power (P = 0.050) during NREM sleep and delta power (P = 0.018) during REM sleep. Regarding attention level, patients with MDD had lower levels of accuracy (P = 0.021), longer mean reaction time (P < 0.001), poorer manifestations of the alerting effect (P = 0.038) and worse executive control (P = 0.048). Moreover, decreased theta power during NREM sleep was correlated with worsened accuracy (β = 0.329, P = 0.040), decreased theta power during REM sleep was correlated with worsened alerting effect (β = 0.355, P = 0.020), and increased delta power during REM sleep was correlated with longer mean reaction time (β = 0.325, P = 0.022) in patients with MDD. No association between ANT performance and other frequency bands was observed in patients with MDD.

Conclusion

Our findings suggest that patients with MDD manifest impaired selective attention function that is associated with decreased theta power during NREM/REM sleep and increased delta power during REM sleep.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

REM parameters in drug-free major depressive disorder: A systematic review and meta-analysis

Previous studies revealed that rapid eye movement (REM) parameters, such as REM latency (RL) and REM density (RD) could be used as electrophysiological markers of depression. Yet these finding should be re-tested in a comorbid-free and drug-free sample. The present systematic review and meta-analysis was conducted to investigate whether drug-free and comorbid-free patients with unipolar depression differentiate from controls with respect to the RL and RD. The PubMed and Web of Science databases were screened from inception to 23 January 2023 for case-control studies comparing RL and RD of patients with unipolar depression and controls. The primary outcome was the standard mean difference. The data were fitted with a random-effects model. Meta-regressions were conducted to investigate patient characteristics and effect size. Publication bias assessment was checked by Egger's Regression and funnel plot asymmetry. Among 43 articles accepted as eligible, 46 RL and 22 RD measurements were included in the meta-analysis. The results indicated shortened RL and increased RD in the patient group than controls. Neither Egger's regression nor funnel plot asymmetry were significant for publication bias. In conclusion, our results tested within drug-free and comorbid-free samples are in line with the literature.

Methods for REM Sleep Density Analysis: A Scoping Review

Rapid eye movements (REM) sleep density is the parameter proposed to explain the variability in the amount of eye movements during REM sleep. Alterations in REM sleep density have been proposed as a screening criterion for individuals with depression and other mental health conditions, but its accuracy has not been properly evaluated. The lack of consensus and the variability of the methods used to score it reduces the external validity of the results, hindering an adequate analysis of its diagnostic accuracy and clinical applicability. This scoping review aimed to identify and quantify the methods used to score REM sleep density, describing their main characteristics. A literature search was conducted in PubMed, Scopus, PsycInfo, and Web of Science. Only studies with objective measures for REM sleep density analysis in individuals with depression were considered eligible. The final sample comprised 57 articles, covering 64 analyses of REM sleep density. The relative frequency methods were the predominant measurement parameter for analyzing REM sleep density across studies. The most frequently adopted REM estimation unit was the number of REM events followed by mini-epochs containing REM. The most common unit of measurement were frequency/time measures. The results demonstrate that there is no consistency in the methods used to calculate REM sleep density in the literature, and a high percentage of studies do not describe their methods in sufficient detail. The most used method was the number of REM episodes per minute of REM sleep, but its use is neither unanimous nor consensual. The methodological inconsistencies and omissions among studies limit the replicability, comparability, and clinical applicability of REM sleep density. Future guidelines should discuss and include a specific methodology for the scoring of REM sleep density, so it can be consensually implemented in clinical services and research.

The Wave Model of Sleep Dynamics and an Invariant Relationship between NonREM and REM Sleep

Explaining the complex structure and dynamics of sleep, which consist of alternating and physiologically distinct nonREM and REM sleep episodes, has posed a significant challenge. In this study, we demonstrate that a single-wave model concept captures the distinctly different overnight dynamics of the four primary sleep measures-the duration and intensity of nonREM and REM sleep episodes-with high quantitative precision for both regular and extended sleep. The model also accurately predicts how these polysomnographic measures respond to sleep deprivation or abundance. Furthermore, the model passes the ultimate test, as its prediction leads to a novel experimental finding-an invariant relationship between the duration of nonREM episodes and the intensity of REM episodes, the product of which remains constant over consecutive sleep cycles. These results suggest a functional unity between nonREM and REM sleep, establishing a comprehensive and quantitative framework for understanding normal sleep and sleep disorders.

Somno-Art Software identifies pathology-induced changes in sleep parameters similarly to polysomnography

Polysomnographic sleep architecture parameters are commonly used to diagnose or evaluate treatment of sleep disorders. Polysomnography (PSG) having practical constraints, the development of wearable devices and algorithms to monitor and stage sleep is rising. Beside pure validation studies, it is necessary for a clinician to ensure that the conclusions drawn with a new generation wearable sleep scoring device are consistent to the ones of gold standard PSG, leading to similar interpretation and diagnosis. This paper reports on the performance of Somno-Art Software for the detection of differences in sleep parameters between patients suffering from obstructive sleep apnea (OSA), insomniac or major depressive disorder (MDD) compared to healthy subjects. On 244 subjects (n = 26 healthy, n = 28 OSA, n = 66 insomniacs, n = 124 MDD), sleep staging was obtained from PSG and Somno-Art analysis on synchronized electrocardiogram and actimetry signals. Mixed model analysis of variance was performed for each sleep parameter. Possible differences in sleep parameters were further assessed with Mann-Whitney U-test between the healthy subjects and each pathology group. All sleep parameters, except N1+N2, showed significant differences between the healthy and the pathology group. No significant differences were observed between Somno-Art Software and PSG, except a 3.6±2.2 min overestimation of REM sleep. No significant interaction 'group'*'technology' was observed, suggesting that the differences in pathologies are independent of the technology used. Overall, comparable differences between healthy subjects and pathology groups were observed when using Somno-Art Software or polysomnography. Somno-Art proposes an interesting valid tool as an aid for diagnosis and treatment follow-up in ambulatory settings.

Predictive Modeling of Mental Illness Onset Using Wearable Devices and Medical Examination Data: Machine Learning Approach

The prevention and treatment of mental illness is a serious social issue. Prediction and intervention, however, have been difficult because of lack of objective biomarkers for mental illness. The objective of this study was to use biometric data acquired from wearable devices as well as medical examination data to build a predictive model that can contribute to the prevention of the onset of mental illness. This was an observational study of 4,612 subjects from the health database of society-managed health insurance in Japan provided by JMDC Inc. The inputs to the predictive model were 3-months of continuous wearable data and medical examinations within and near that period; the output was the presence or absence of mental illness over the following month, as defined by insurance claims data. The features relating to the wearable data were sleep, activity, and resting heart rate, measured by a consumer-grade wearable device (specifically, Fitbit). The predictive model was built using the XGBoost algorithm and presented an area-under-the-receiver-operating-characteristic curve of 0.712 (SD = 0.02, a repeated stratified group 10-fold cross validation). The top-ranking feature importance measure was wearable data, and its importance was higher than the blood-test values from medical examinations. Detailed verification of the model showed that predictions were made based on disrupted sleep rhythms, mild physical activity duration, alcohol use, and medical examination data on disrupted eating habits as risk factors. In summary, the predictive model showed useful accuracy for grouping the risk of mental illness onset, suggesting the potential of predictive detection, and preventive intervention using wearable devices. Sleep abnormalities in particular were detected as wearable data 3 months prior to mental illness onset, and the possibility of early intervention targeting the stabilization of sleep as an effective measure for mental illness onset was shown.

Sleep complaints are associated with increased suicide risk independently of psychiatric disorders: results from a national 3-year prospective study

Prior research suggests that sleep disturbances are associated with increased risk of suicide. However, sleep disturbances are associated with a wide range of psychiatric disorders, and it is unknown whether this association is independent of psychopathology. In a large nationally representative prospective survey, the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), we used structural equation modeling to examine the shared and specific effects of three sleep complaints (i.e., trouble falling asleep, early morning awakening, and hypersomnia) on the 3-year occurrence of attempting suicide. Because psychiatric disorders increase the risk of suicide attempt almost exclusively through a general psychopathology factor representing their shared effect, covariates included that factor, prior history of suicide attempt, and a wide range of sociodemographic and clinical characteristics. The 3-year prevalence rate of suicide attempt was 0.6% (n = 241). Compared with participants who did not attempt suicide between the two waves, those who did reported significantly more frequently having trouble falling asleep (44.6% vs. 16.6%), early morning awakening (38.9% vs. 12.7%), and hypersomnia (35.0% vs. 10.7%). Following adjustments, effects of sleep complaints on this risk were significant and exerted almost exclusively through a general sleep complaints factor representing the shared effect across all sleep complaints. There were no residual associations of any individual sleep complaint with attempting suicide above that association. Sleep complaints are associated with an increased risk of attempting suicide independently of psychopathology, and should be included in suicide risk assessments as these symptoms may provide targets for reducing the risks of suicidal behaviors.

A meta-analysis of the relationship between subjective sleep and depressive symptoms in adolescence

BACKGROUND

Adolescence is a risk period for the development of mental illness, as well as a time for pronounced change in sleep behaviour. While prior studies, including several meta-analyses show a relationship between sleep and depressive symptoms, there were many inconsistences found in the literature.

OBJECTIVE

To investigate the relationship between subjective sleep and depressive symptoms.

METHODS

Following PRISMA guidelines, we conducted a literature search that yielded forty-nine recent studies (2014-2020) with adolescent samples aged 9 to 25-year-olds, and more than double the sample size of previous meta-analyses (N = 318,256).

RESULTS

In a series of meta-analyses, we show that while several common categories of subjective sleep are associated with depressive symptoms in adolescents, the strength of this relationship varies. Measures of sleep perception: poor sleep quality (r = 0.41), insomnia (r = 0.37), sleep disturbances (r = 0.36), wake after sleep onset (r = 0.31), and daytime sleepiness (r = 0.30) correlated more strongly with depressive symptoms, than measures of sleep behaviour: sleep latency (r = 0.22), and sleep duration (r = -0.19).

CONCLUSIONS

These findings suggest that in studies of depressive symptoms it may be important to assess an adolescent's perception about their sleep, in addition to their sleep/wake behaviours.

Ablation of olfactory bulb glutamatergic neurons induces depressive-like behaviors and sleep disturbances in mice

RATIONALE

Major depression is a serious, but common, psychological disorder, which consists of a long-lasting depressive mood, feelings of helplessness, anhedonia, and sleep disturbances. It has been reported that rats with bilateral olfactory bulbectomies (OBXs) exhibit depressive-like behaviors which indicates that the olfactory bulb (OB) plays an important role in the formation of depression. However, which type of OB neurons plays an important role in the formation of depression remains unclear.

OBJECTIVE

To determine the role of OB neuronal types in depression and related sleep-wake dysfunction.

METHODS

Firstly, we established and evaluated a conventional physical bilateral OBX depression model. Secondly, we used chemical methods to ablate OB neurons, while maintaining the original shape, and evaluated depressive-like behaviors. Thirdly, we utilized AAV-flex-taCasp3-TEVp and transgenetic mice to specifically ablate the OB GABAergic or glutamatergic neurons, then evaluated depressive-like behaviors.

RESULTS

Compared with measured parameters in sham mice, mice with OBXs or ibotenic acid-induced OB lesions exhibited depressive-like behaviors and sleep disturbances, as demonstrated by results of depressive-like behavior tests and sleep recordings. Selective lesioning of OB glutamatergic neurons, but not GABAergic neurons induced depressive-like behaviors and increased rapid eye movement sleep during the light phase of the circadian cycle.

CONCLUSIONS

These results indicate that OB glutamatergic neurons play a key role in olfactory-related depression and sleep disturbance.

Sleep disturbance and psychiatric disorders

Signs of mental ill health that cut across psychiatric diagnostic categories at high rates are typically viewed as non-specific occurrences, downgraded in importance and disregarded. However, problems not associated with particular diagnoses should be expected if there is shared causation across mental health conditions. If dynamic networks of interacting symptoms are the reality of mental health presentations, then particularly disruptive and highly connected problems should be especially common. The non-specific occurrence might be highly consequential. One non-specific occurrence that is often overlooked is patients' chronic difficulty in getting good sleep. In this Review, we consider whether disrupted sleep might be a contributory causal factor in the occurrence of major types of mental health disorders. It is argued that insomnia and other mental health conditions not only share common causes but also show a bidirectional relationship, with typically the strongest pathway being disrupted sleep as a causal factor in the occurrence of other psychiatric problems. Treating insomnia lessens other mental health problems. Intervening on sleep at an early stage might be a preventive strategy for the onset of clinical disorders. Our recommendations are that insomnia is assessed routinely in the occurrence of mental health disorders; that sleep disturbance is treated in services as a problem in its own right, yet also recognised as a pathway to reduce other mental health difficulties; and that access to evidence-based treatment for sleep difficulties is expanded in mental health services.

Sleep therapeutics and neuropsychiatric illness

Alterations in sleep are extremely common in patients with neuropsychiatric illness. In addition, sleep disorders such as insomnia, obstructive sleep apnea, rapid eye movement sleep behavior disorder, and circadian rhythm disorders commonly occur at a rate greater than the general population in neuropsychiatric conditions. Historically, sleep problems have been viewed as symptoms of associated neuropsychiatric disorders. However, there is increasing evidence suggesting a complex inter-relationship with possible bidirectional causality. The inter-relatedness of these conditions represents an opportunity for understanding mechanisms and improving clinical treatment. To the extent that sleep problems affect neuropsychiatric conditions, it may be possible to address sleep problems and have a positive impact on the course of neuropsychiatric illnesses. Further, some treatments for sleep disorders have direct effects on neuropsychiatric illnesses that may be unrelated to their effects on sleep disorders. Similarly, neuropsychiatric conditions and their treatments can affect sleep and sleep disorders. This article reviews available evidence on the effects of therapies for sleep disorders on neuropsychiatric conditions and also secondarily considers the impacts of therapies for neuropsychiatric conditions on sleep. Primary goals of this review are to identify gaps in current research, to determine the extent to which the cross-therapeutic effects of these treatments help to elucidate therapeutic or pathological mechanisms, and to assist clinicians in optimizing therapeutic choice in patients with sleep disorders and neuropsychiatric conditions.

Diagnostic Utility of Sodium Lactate Infusion and CO2-35% Inhalation for Panic Disorder

Laboratory measures have played an integral role in diagnosing pathology; however, compared to traditional medicine, psychiatric medicine has lagged behind in using such measures. A growing body of literature has begun to examine the viability and development of different laboratory measures in order to diagnose psychopathologies. The present review examines the current state of development of both sodium lactate infusion and CO2-35% inhalation as potential ancillary measures to diagnose panic disorder (PD). A previously established 3-step approach to identifying laboratory-based diagnostic tests was applied to available literature assessing the ability of both sodium lactate infusion or CO2-35% inhalation to induce panic attacks in PD patients, healthy controls, and individuals with other psychiatric conditions. Results suggest that across the literature reviewed, individuals with PD were more likely to exhibit panic attacks following administration of sodium lactate or CO2-35% compared to control participants. The majority of the studies examined only compared individuals with PD to healthy controls, suggesting that these ancillary measures are underdeveloped. In order to further determine the utility of these ancillary measures, research is needed to determine if panic attacks following administration of these chemical agents are unique to PD, or if individuals with related pathologies also respond, which may be indicative of transdiagnostic characteristics found across disorders.

Associations Among Trajectories of Sleep Disturbance, Depressive Symptomology and 24-Hour Urinary Cortisol in HIV+ Women Following a Stress Management Intervention

Objective: The burden of sleep disturbance and depressive symptomology is high for persons living with HIV and particularly so for women. While cognitive behavioral stress management (CBSM) is shown to reduce symptoms of depression and 24-hr urinary free cortisol output (CORT) in HIV+ men, less is known about the effects of CBSM on mood and concomitant sleep disturbance in HIV+ women. The study aim is to model longitudinal change in sleep disturbance, depressive symptomology, and CORT for HIV+ women exposed to a 12-week CBSM intervention or control condition. Methods: Self-reported sleep quality and depressive symptomology, along with CORT, was collected from surveys at baseline and approximately every three months thereafter for nine months from 130 HIV+ women (M_age = 38.44, SD = 7.73). The data was used to specify a parallel process latent growth model with CORT as a time-varying covariate. Results: The model showed acceptable fit. There was a linear decline in sleep disturbance (β = -0.32, p < .05) and logarithmic decline in depressive symptomology (β = -0.33, p < .05) for those receiving the intervention. Decline in sleep disturbance predicted lower CORT at nine months. Furthermore, having less depressive symptoms at baseline was associated with lower initial levels of sleep disturbance and greater improvement in sleep quality over time. There was no discernible association between sleep and mood disturbance in the control group. Across groups, there was a consistent association between older age and greater sleep disturbance (r = 0.34, p < .01). Conclusion: Sleep disturbance appears to be a behavioral target for CBSM in HIV+ women although older age, preintervention levels of depressive mood, and time-varying levels of CORT output may limit improvement in sleep quality over time.

Insomnia as a Moderator of Response to Time in Bed Restriction for Augmenting Antidepressant Treatment: A Preliminary Investigation

BACKGROUND

There are complex, bidirectional associations between major depressive disorder and insomnia. In the present study, we evaluated insomnia as a moderator of response to antidepressant therapy in the context of a sleep manipulation (time in bed restriction) for major depressive disorder.

METHODS

Fifty-eight adults with major depressive disorder received 8 weeks of fluoxetine 20-40 mgs and were randomized to 8 hr time in bed (8h TIB) or 6 hr time in bed (6h TIB) for the first 2 weeks (participants in the 6h TIB condition were further randomized to a delayed bedtime (Late Bedtime) or advanced rise time (Early Rise Time) group). Insomnia was assessed at baseline using the Insomnia Severity Index. Depression symptom severity was determined by the clinician-rated 17-item Hamilton Rating Scale for Depression (HAMD-17), completed weekly.

RESULTS

A group by time interaction was observed whereby HAMD-17 scores were higher for participants assigned to the 6h TIB group (without insomnia, weeks 3 through 7; with insomnia from week 3 through 6, ps < .05) relative to participants without insomnia assigned to the 8h TIB group. There were no differences in HAMD-17 scores for participants with insomnia in the 6h TIB group relative to the 8h TIB group.

CONCLUSION

These preliminary findings suggest that response to fluoxetine may be hindered by TIB restriction in individuals without insomnia. Individuals with insomnia respond similarly to fluoxetine regardless of whether their TIB is restricted. Limitations include exclusive use of self-report measures to categorize insomnia, and small sample sizes in several of the subgroups.

Insomnia and hypersomnia in major depressive episode: Prevalence, sociodemographic characteristics and psychiatric comorbidity in a population-based study

OBJECTIVES

To examine (i) the frequency of different sleep complaints (early wake-up, trouble falling asleep, hypersomnia) and their co-occurrence and (ii) the sociodemographic characteristics and psychiatric comorbidity associated with each type of sleep profiles.

METHODS

Data were drawn from the Wave 2 National Epidemiologic Survey on Alcohol and Related Conditions, a nationally representative survey of the US adult population (wave 1, 2001-2002; wave 2, 2004-2005). The primary analyses were limited to 3573 participants who had a DSM-IV-TR diagnosis of major depressive episode (MDE) between the two waves. We used a multiple regression model to estimate the strength of independent associations between self-reported sleep complaints, sociodemographic characteristics and lifetime psychiatric comorbidity.

RESULTS

Most of participants with MDE (92%) reported significant sleep complaints, from whom 85.2% had insomnia and 47.5% hypersomnia symptoms. The prevalence rates were for insomnia "only" of 48.5%, hypersomnia "only" of 13.7%, and their co-occurrence of 30.2%. We found that several sociodemographic characteristics (gender, age, education, individual and familial income, marital status) and psychiatric disorders (bipolar disorders, post-traumatic disorders and panic disorder) were significantly and independently associated with different sleep profiles. The co-occurrence of insomnia (especially early wake-up) and hypersomnia presented with a two-/three- fold increase risk of bipolar disorders.

LIMITATIONS

Definitions of sleep complaints were qualitative and subjective.

CONCLUSION

Sleep complaints are prevalent and heterogeneous in expression during MDE. Sleep disturbance profiles are associated with specific patterns of comorbidity. Our findings highlight the importance of continued research on sleep complaints during MDE while taking into account psychiatric comorbidity.

Differences in rapid eye movement (REM) sleep abnormalities between posttraumatic stress disorder (PTSD) and major depressive disorder patients: REM interruption correlated with nightmare complaints in PTSD

OBJECTIVE

The presence of repeated nightmares in posttraumatic stress disorder (PTSD) has been hypothesized as a dysfunction of rapid eye movement (REM) sleep, but there has been remarkably little agreement about the pathophysiology. This presents a deterrent to more effective treatments. REM sleep abnormalities including elevated REM density also have been replicated in major depressive disorder (MDD). The purpose of this study was to clarify the difference of REM sleep abnormalities between the two disorders for understanding the pathophysiology of sleep disturbances in PTSD.

METHODS

Polysomnographic measures were compared among 14 PTSD patients (aged 23.7 ± 5.5 years) and 14 MDD patients (aged 27.9 ± 10.1 years) under drug-naive or drug-free conditions. We defined REM interruption by summing the intrusive wake times during the REM period and adding the subsequent wake times to the last epoch of REM period. The significant polysomnographic measures were correlated with PTSD symptoms within the PTSD group.

RESULTS

REM interruption was significantly increased in the PTSD group compared with the MDD group (12.2 vs 2.1 min, p = 0.001). REM density was also significantly increased in the PTSD group compared with the MDD group (30.5 vs 23.1%, p = 0.019). Within the PTSD group, we found significant correlations between the severity of trauma-related nightmare complaints and the percentage of REM interruption (R = 0.62, p = 0.017), but not REM density.

CONCLUSIONS

REM sleep abnormalities are different between PTSD and MDD. Increased REM interruption may be a biological marker correlated with nightmare complaints in PTSD patients. Treatments including pharmacotherapy that reduces REM interruption might ameliorate nightmares in PTSD.

The Safety, Tolerability and Risks Associated with the Use of Newer Generation Antidepressant Drugs: A Critical Review of the Literature

Newer generation antidepressant drugs (ADs) are widely used as the first line of treatment for major depressive disorders and are considered to be safer than tricyclic agents. In this critical review, we evaluated the literature on adverse events, tolerability and safety of selective serotonin reuptake inhibitors, serotonin noradrenaline reuptake inhibitors, bupropion, mirtazapine, trazodone, agomelatine, vilazodone, levomilnacipran and vortioxetine. Several side effects are transient and may disappear after a few weeks following treatment initiation, but potentially serious adverse events may persist or ensue later. They encompass gastrointestinal symptoms (nausea, diarrhea, gastric bleeding, dyspepsia), hepatotoxicity, weight gain and metabolic abnormalities, cardiovascular disturbances (heart rate, QT interval prolongation, hypertension, orthostatic hypotension), genitourinary symptoms (urinary retention, incontinence), sexual dysfunction, hyponatremia, osteoporosis and risk of fractures, bleeding, central nervous system disturbances (lowering of seizure threshold, extrapyramidal side effects, cognitive disturbances), sweating, sleep disturbances, affective disturbances (apathy, switches, paradoxical effects), ophthalmic manifestations (glaucoma, cataract) and hyperprolactinemia. At times, such adverse events may persist after drug discontinuation, yielding iatrogenic comorbidity. Other areas of concern involve suicidality, safety in overdose, discontinuation syndromes, risks during pregnancy and breast feeding, as well as risk of malignancies. Thus, the rational selection of ADs should consider the potential benefits and risks, likelihood of responsiveness to the treatment option and vulnerability to adverse events. The findings of this review should alert the physician to carefully review the appropriateness of AD prescription on an individual basis and to consider alternative treatments if available.

Sex Differences in the Relationship Between Depressive Symptoms and Actigraphic Assessments of Sleep and Rest-Activity Rhythms in a Population-Based Sample

OBJECTIVE

Depression is often associated with disruptions in sleep and circadian rhythms. We aimed to confirm these relationships via actigraphic assessment in a large, population-based sample and test whether sex moderates these relationships.

METHODS

A total of 418 participants (age = 35-85 years, mean [standard deviation] = 57.04 [11.47]) completed questionnaires and 1 week of actigraphy, used to calculate sleep and rest-activity statistics including mesor (mean activity level), amplitude (height of rhythm), and acrophase (time of day that rhythm peaks).

RESULTS

Depressive symptoms, assessed via Center for Epidemiologic Studies Depression Scale, were associated with disrupted sleep and rest-activity rhythms. Furthermore, men demonstrated longer sleep onset latency (SOL, B = -13.28, p < .001), longer wake time after sleep onset (B = -6.26, p < .01), lower sleep efficiency (B = 5.91, p < .001), and lower total sleep time (TST, B = 33.16, p < .001) than women. Sex moderated the relationship between depression and SOL, TST, mesor, and amplitude; sex-stratified models revealed that higher depression scores were associated with greater SOL (B = 1.05, p < .001) and less TST (B = -0.87, p < .10) for women with higher depressive symptoms, but lower mesor (B = -1.75, p < .01) and amplitude (B = -1.94, p < .01) for men with higher depressive symptoms.

CONCLUSIONS

Depressive symptoms were related to disrupted sleep continuity and rest-activity rhythms in this population-based sample; however, these relationships differed by sex. Women with greater depressive symptoms exhibited difficulty with sleep continuity, whereas men with greater depressive symptoms demonstrated disruption throughout the 24-hour rhythm.

Depressive Symptoms Are Associated With Objectively Measured Sleep Parameters in Kidney Transplant Recipients

STUDY OBJECTIVES

Both depression and sleep complaints are very prevalent among kidney transplant (kTx) recipients. However, details of the complex relationship between sleep and depression in this population are not well documented. Thus, we investigated the association between depressive symptoms and sleep macrostructure parameters among prevalent kTx recipients.

METHODS

Ninety-five kTx recipients participated in the study (54 males, mean ± standard devation age 51 ± 13 years, body mass index 26 ± 4 kg/m2, estimated glomerular filtration rate 53 ± 19 ml/min/1.73 m2). Symptoms of depression were assessed by the Center for Epidemiologic Studies - Depression Scale (CES-D). After 1-night polysomnography each recording was visually scored and sleep macrostructure was analyzed.

RESULTS

The CES-D score was significantly associated with the amount of stage 2 sleep (r = 0.20, P < .05), rapid eye movement (REM) latency (r = 0.21, P < .05) and REM percentage (r = -0.24, P < .05), but not with the amount of slow wave sleep (r = -0.12, P > .05). In multivariable linear regression models the CES-D score was independently associated with the amount of stage 2 sleep (β: 0.205; confidence interval: 0.001-0.409; P = .05) and REM latency (β: 0.234; confidence interval: 0.001-0.468; P = .05) after adjustment for potential confounders.

CONCLUSIONS

Depressive symptoms among kTx recipients are associated with increased amount of stage 2 sleep and prolonged REM latency. Further studies are needed to confirm our findings and understand potential clinical implications.

24-h activity rhythm and sleep in depressed outpatients

Disturbances in sleep and circadian rest-activity rhythms are key features of depression. Actigraphy, a non-invasive method for monitoring motor activity, can be used to objectively assess circadian rest-activity rhythms and sleep patterns. While recent studies have measured sleep and daytime activity of depressed patients using wrist-worn actigraphy, the actigraphic 24-h rest-activity rhythm in depression has not been well documented. We aimed to examine actigraphically measured sleep and circadian rest-activity rhythms in depressed outpatients. Twenty patients with DSM-IV major depressive episode and 20 age- and sex-matched healthy controls participated in this study. Participants completed 7 consecutive days of all-day actigraphic activity monitoring while engaging in usual activities. For sleep parameters, total sleep time, wake after sleep onset, and sleep fragmentation index were determined. Circadian rhythms were estimated by fitting individual actigraphy data to a cosine curve of a 24-h activity rhythm using the cosinor method, which generated three circadian activity rhythm parameters, i.e., MESOR (rhythm-adjusted mean), amplitude, and acrophase. Subjective sleep was also assessed using a sleep diary and the Pittsburgh Sleep Quality Index. Patients showed significantly lower MESOR and more dampened amplitude along with significant sleep disturbances. Logistic regression analysis revealed that lower MESOR and more fragmented sleep emerged as the significant predictors of depression. Correlations between subjectively and actigraphically measured parameters demonstrated the validity of actigraphic measurements. These results indicate marked disturbances in sleep and circadian rest-activity rhythms of depression. By simultaneously measuring sleep and rest-activity rhythm parameters, actigraphy might serve as an objective diagnostic aid for depression.

CNS- and ANS-arousal predict response to antidepressant medication: Findings from the randomized iSPOT-D study

Arousal systems are one of the recently announced NIMH Research Domain Criteria to inform future diagnostics and treatment prediction. In major depressive disorder (MDD), altered central nervous system (CNS) wakefulness regulation and an increased sympathetic autonomic nervous system (ANS) activity have been identified as biomarkers with possible discriminative value for prediction of antidepressant treatment response. Therefore, the hypothesis of a more pronounced decline of CNS and ANS-arousal being predictive for a positive treatment outcome to selective-serotonin-reuptake-inhibitor (SSRI) treatment was derived from a small, independent exploratory dataset (N = 25) and replicated using data from the randomized international Study to Predict Optimized Treatment Response in Depression (iSPOT-D). There, 1008 MDD participants were randomized to either a SSRI (escitalopram or sertraline) or a serotonin-norepinephrine-reuptake-inhibitor (SNRI-venlafaxine) arm. Treatment response was established after eight weeks using the 17-item Hamilton Rating Scale for Depression. CNS-arousal (i.e. electroencephalogram-vigilance), ANS-arousal (heart rate) and their change across time were assessed during rest. Responders and remitters to SSRI treatment were characterized by a faster decline of CNS-arousal during rest whereas SNRI responders showed a significant increase of ANS-arousal. Furthermore, SSRI responders/remitters showed an association between ANS- and CNS-arousal regulation in comparison to non-responders/non-remitters while this was not the case for SNRI treatment arm. Since positive treatment outcome to SSRI and SNRI was linked to distinct CNS and ANS-arousal profiles, these predictive markers probably are not disorder specific alterations but reflect the responsiveness of the nervous system to specific drugs.

Effects of the Synthetic Neurosteroid: 3β-Methoxypregnenolone (MAP4343) on Behavioral and Physiological Alterations Provoked by Chronic Psychosocial Stress in Tree Shrews

BACKGROUND

Most currently available active antidepressant drugs are selective serotonin/noradrenaline reuptake inhibitors. However, as their clinical efficacy is not immediate, long-term administration is often accompanied by substantial side effects, and numerous patients remain non- or partial responders. We have recently found that the synthetic neurosteroid derivative 3β-methoxypregnenolone, which binds to the microtubule-associated protein-2, can provide a novel therapeutic approach in experimental model of depressive disorders in rats. To further validate the antidepressant-like efficacy of 3β-methoxypregnenolone, we investigated effects of a longer treatment (4-week oral administration; 50mg/kg/d) in a nonrodent species, the tree shrew, exposed to psychosocial stress that elicits close-to-human alterations observed in patients with depressive disorders.

METHODS

During the experimental period, physiological parameters were registered, including core body temperature and electroencephalogram, while animals were videotaped to analyze their avoidance behavior. Morning urine samples were collected for measurements of cortisol and noradrenaline levels.

RESULTS

We found that treatment with 3β-methoxypregnenolone abolished stress-triggered avoidance behavior and prevented hormone hypersecretion, hypothermia, and sleep disturbances, further suggesting its antidepressant-like efficacy. Comparative treatment with fluoxetine also prevented some of the physiological alterations, while the hypersecretion of cortisol and sleep disturbances were not or partially restored by fluoxetine, suggesting a better efficacy of 3β-methoxypregnenolone. Alpha-tubulin isoforms were measured in hippocampi: we found that 3β-methoxypregnenolone reversed the specific decrease in acetylation of α-tubulin induced by psychosocial stress, while it did not modify the psychosocial stress-elicited reduction of tyrosinated α-tubulin.

CONCLUSIONS

Taken together, these data strongly suggest a potent antidepressant-like effect of 3β-methoxypregnenolone on translational parameters.

Differentiated effects of the multimodal antidepressant vortioxetine on sleep architecture: Part 2, pharmacological interactions in rodents suggest a role of serotonin-3 receptor antagonism

Antidepressants often disrupt sleep. Vortioxetine, a multimodal antidepressant acting through serotonin (5-HT) transporter (SERT) inhibition, 5-HT3, 5-HT7 and 5-HT1D receptor antagonism, 5-HT1B receptor partial agonism, and 5-HT1A receptor agonism, had fewer incidences of sleep-related adverse events reported in depressed patients. In the accompanying paper a polysomnographic electroencephalography (sleep-EEG) study of vortioxetine and paroxetine in healthy subjects indicated that at low/intermediate levels of SERT occupancy, vortioxetine affected rapid eye movement (REM) sleep differently than paroxetine. Here we investigated clinically meaningful doses (80-90% SERT occupancy) of vortioxetine and paroxetine on sleep-EEG in rats to further elucidate the serotoninergic receptor mechanisms mediating this difference. Cortical EEG, electromyography (EMG), and locomotion were recorded telemetrically for 10 days, following an acute dose, from rats receiving vortioxetine-infused chow or paroxetine-infused water and respective controls. Sleep stages were manually scored into active wake, quiet wake, and non-REM or REM sleep. Acute paroxetine or vortioxetine delayed REM onset latency (ROL) and decreased REM episodes. After repeated administration, vortioxetine yielded normal sleep-wake rhythms while paroxetine continued to suppress REM. Paroxetine, unlike vortioxetine, increased transitions from non-REM to wake, suggesting fragmented sleep. Next, we investigated the role of 5-HT3 receptors in eliciting these differences. The 5-HT3 receptor antagonist ondansetron significantly reduced paroxetine's acute effects on ROL, while the 5-HT3 receptor agonist SR57227A significantly increased vortioxetine's acute effect on ROL. Overall, our data are consistent with the clinical findings that vortioxetine impacts REM sleep differently than paroxetine, and suggests a role for 5-HT3 receptor antagonism in mitigating these differences.

Association Between Benzodiazepine Use and Epilepsy Occurrence: A Nationwide Population-Based Case-Control Study

We conducted a retrospective case-control study to evaluate the association between the risk of benzodiazepine (BZD) use and epilepsy occurrence by using data from the Taiwan National Health Insurance Research Database. We recruited 1065 participants who ages 20 years or older and newly diagnosed with epilepsy (International Classification of Diseases, Ninth Revision, Clinical Modification 345) between 2004 and 2011 and assigned them to the epilepsy group. We subsequently frequency-matched them with participants in a control group (n = 4260) according to sex, age, and index year at a 1:4 ratio. A logistic regression model was employed to calculate the odds ratio (OR) for association of epilepsy with BZD exposure. Multivariate logistic regression was conducted to estimate the dose-response relationship between BZD levels and epilepsy risk. The adjusted OR (aOR) for the association of epilepsy with BZD exposure was 2.02 (95% confidence interval [CI] = 1.68-2.42). The aOR for an average BZD dose increased to 1.26 for the participants on <0.01 defined daily dose (DDD), and increased to 4.32 for those on ≥1.50 DDD. On average, when the DDD of BZD exposure increased by 100 units, the epilepsy risk increase by 1.03-fold (95% CI = 1.01-1.04, P = 0.003). The annual BZD exposure day ranges were significantly associated with epilepsy (2-7 days: aOR = 1.67; 8-35 days: aOR = 3.16; and ≥35 days: aOR = 5.60). Whenever the annual BZD exposure increased by 30 days, the risk of epilepsy notably increased by 1.03-fold (95% CI = 1.01-1.04, P < 0.001). In addition, users who quit BZD for more than 6 months still exhibited a higher risk of epilepsy than did the non-BZD users. A considerable increase in epilepsy occurrence was observed in ones with BZD use, particularly in those with prolonged use, multiple exposure, and high-dose consumption.

Inhibition of tumor necrosis factor improves sleep continuity in patients with treatment resistant depression and high inflammation

Blockade of the inflammatory cytokine tumor necrosis factor (TNF) in depressed patients with increased inflammation has been associated with decreased depressive symptoms. Nevertheless, the impact of TNF blockade on sleep in depressed patients has not been examined. Accordingly, sleep parameters were measured using polysomnography in 36 patients with treatment resistant major depression at baseline and 2weeks after 3 infusions (week 8) of either the TNF antagonist infliximab (n=19) or placebo (n=17). Markers of inflammation including c-reactive protein (CRP) and TNF and its soluble receptors were also assessed along with depression measured by the 17-item Hamilton Depression Rating Scale. No differences in sleep parameters were found as a function of infliximab treatment over time. Nevertheless, wake after sleep onset (WASO), the spontaneous arousal index and sleep period time significantly decreased, and sleep efficiency significantly increased, from baseline to week 8 in infliximab-treated patients with high (CRP>5mg/L) (n=9) versus low inflammation (CRP⩽5mg/L) (n=10), controlling for changes in scores of depression. Stage 2 sleep also significantly decreased in infliximab-treated patients with high versus low inflammation. Decreases in soluble TNF receptor 1 (sTNFR1) significantly correlated with decreases in WASO and increases in sleep efficiency in infliximab-treated subjects with high inflammation. Placebo-treated subjects exhibited no sleep changes as a function of inflammation, and no correlations between inflammatory markers and sleep parameters in placebo-treated patients were found. These data suggest that inhibition of inflammation may be a viable strategy to improve sleep alterations in patients with depression and other disorders associated with increased inflammation.

Robust disruptions in electroencephalogram cortical oscillations and large-scale functional networks in autism

BACKGROUND

Autism spectrum disorders (ASD) are increasingly prevalent and have a significant impact on the lives of patients and their families. Currently, the diagnosis is determined by clinical judgment and no definitive physiological biomarker for ASD exists. Quantitative biomarkers obtainable from clinical neuroimaging data - such as the scalp electroencephalogram (EEG) - would provide an important aid to clinicians in the diagnosis of ASD. The interpretation of prior studies in this area has been limited by mixed results and the lack of validation procedures. Here we use retrospective clinical data from a well-characterized population of children with ASD to evaluate the rhythms and coupling patterns present in the EEG to develop and validate an electrophysiological biomarker of ASD.

METHODS

EEG data were acquired from a population of ASD (n = 27) and control (n = 55) children 4-8 years old. Data were divided into training (n = 13 ASD, n = 24 control) and validation (n = 14 ASD, n = 31 control) groups. Evaluation of spectral and functional network properties in the first group of patients motivated three biomarkers that were computed in the second group of age-matched patients for validation.

RESULTS

Three biomarkers of ASD were identified in the first patient group: (1) reduced posterior/anterior power ratio in the alpha frequency range (8-14 Hz), which we label the "peak alpha ratio", (2) reduced global density in functional networks, and (3) a reduction in the mean connectivity strength of a subset of functional network edges. Of these three biomarkers, the first and third were validated in a second group of patients. Using the two validated biomarkers, we were able to classify ASD subjects with 83 % sensitivity and 68 % specificity in a post-hoc analysis.

CONCLUSIONS

This study demonstrates that clinical EEG can provide quantitative biomarkers to assist diagnosis of autism. These results corroborate the general finding that ASD subjects have decreased alpha power gradients and network connectivities compared to control subjects. In addition, this study demonstrates the necessity of using statistical techniques to validate EEG biomarkers identified using exploratory methods.