Sleep and circadian functioning: critical mechanisms in the mood disorders?

The association between biological rhythms, depression, and functioning in bipolar disorder: a large multi-center study

OBJECTIVE

We examined the relationship between biological rhythms and severity of depressive symptoms in subjects with bipolar disorder and the effects of biological rhythms alterations on functional impairment.

METHOD

Bipolar patients (n = 260) and healthy controls (n = 191) were recruited from mood disorders programs in three sites (Spain, Brazil, and Canada). Parameters of biological rhythms were measured using the Biological Rhythms Assessment in Neuropsychiatry (BRIAN), an interviewer administered questionnaire that assesses disruptions in sleep, eating patterns, social rhythms, and general activity.

RESULTS

Multivariate analyses of covariance showed significant intergroup differences after controlling for potential confounders (Pillai's F = 49.367; df = 2, P < 0.001). Depressed patients had the greatest biological rhythms disturbance, followed by patients with subsyndromal symptoms, euthymic patients, and healthy controls. Biological rhythms and HAMD scores were independent predictors of poor functioning (F = 12.841, df = 6, P < 0.001, R²  = 0.443).

CONCLUSION

Our study shows a dose-dependent association between the severity of depressive symptoms and degree of biological rhythms disturbance. Biological rhythms disturbance was also an independent predictor of functional impairment. Although the directionality of this relationship remains unknown, our results suggest that stability of biological rhythms should be an important target of acute and long-term management of bipolar disorder and may aid in the improvement of functioning.

Functional Implications of the CLOCK 3111T/C Single-Nucleotide Polymorphism

Circadian rhythm disruptions are prominently associated with bipolar disorder (BD). Circadian rhythms are regulated by the molecular clock, a family of proteins that function together in a transcriptional-translational feedback loop. The CLOCK protein is a key transcription factor of this feedback loop, and previous studies have found that manipulations of the Clock gene are sufficient to produce manic-like behavior in mice (1). The CLOCK 3111T/C single-nucleotide polymorphism (SNP; rs1801260) is a genetic variation of the human CLOCK gene that is significantly associated with increased frequency of manic episodes in BD patients (2). The 3111T/C SNP is located in the 3'-untranslated region of the CLOCK gene. In this study, we sought to examine the functional implications of the human CLOCK 3111T/C SNP by transfecting a mammalian cell line (mouse embryonic fibroblasts isolated from Clock(-/-) knockout mice) with pcDNA plasmids containing the human CLOCK gene with either the T or C SNP at position 3111. We then measured circadian gene expression over a 24-h time period. We found that the CLOCK3111C SNP resulted in higher mRNA levels than the CLOCK 3111T SNP. Furthermore, we found that Per2, a transcriptional target of CLOCK, was also more highly expressed with CLOCK 3111C expression, indicating that the 3'-UTR SNP affects the expression, function, and stability of CLOCK mRNA.

Interpersonal Psychotherapy for Adolescents With Mood and Behavior Dysregulation: Evidence-Based Case Study

Interpersonal psychotherapy for depressed adolescents, an evidence-based psychotherapy, has been adapted for youth with chronic irritability and excessive reactivity (i.e., temper outbursts), to create Interpersonal Psychotherapy for Mood and Behavior Dysregulation (IPT-MBD). Youth with chronic irritability and excessive reactivity were originally conceptualized as severe mood dysregulation (SMD) and in the Diagnostic and Statistical Manual of Mental Disorders (5th ed.) as disruptive mood dysregulation disorder. Because outbursts are the most prominent symptom, behavioral management strategies are typically a common focus of treatment. These outbursts, along with other mood symptoms, result in significant impairment in multiple domains, with a particularly adverse impact on interpersonal functioning. For this reason improving relationships is an important target for treatment. We present an evidence-based case study of an adolescent who met research criteria for SMD and who received the IPT-MBD intervention as part of a research study. Monthly ratings assessing severity and improvement of SMD symptoms were conducted by an independent evaluator. This adolescent had an overall improvement in SMD symptoms, attended all scheduled therapy sessions, and parent and teen reported satisfaction with the treatment. We discuss factors that may influence the effectiveness of this treatment.

Royal Australian and New Zealand College of Psychiatrists clinical practice guidelines for mood disorders

OBJECTIVES

To provide guidance for the management of mood disorders, based on scientific evidence supplemented by expert clinical consensus and formulate recommendations to maximise clinical salience and utility.

METHODS

Articles and information sourced from search engines including PubMed and EMBASE, MEDLINE, PsycINFO and Google Scholar were supplemented by literature known to the mood disorders committee (MDC) (e.g., books, book chapters and government reports) and from published depression and bipolar disorder guidelines. Information was reviewed and discussed by members of the MDC and findings were then formulated into consensus-based recommendations and clinical guidance. The guidelines were subjected to rigorous successive consultation and external review involving: expert and clinical advisors, the public, key stakeholders, professional bodies and specialist groups with interest in mood disorders.

RESULTS

The Royal Australian and New Zealand College of Psychiatrists clinical practice guidelines for mood disorders (Mood Disorders CPG) provide up-to-date guidance and advice regarding the management of mood disorders that is informed by evidence and clinical experience. The Mood Disorders CPG is intended for clinical use by psychiatrists, psychologists, physicians and others with an interest in mental health care.

CONCLUSIONS

The Mood Disorder CPG is the first Clinical Practice Guideline to address both depressive and bipolar disorders. It provides up-to-date recommendations and guidance within an evidence-based framework, supplemented by expert clinical consensus.

MOOD DISORDERS COMMITTEE

Professor Gin Malhi (Chair), Professor Darryl Bassett, Professor Philip Boyce, Professor Richard Bryant, Professor Paul Fitzgerald, Dr Kristina Fritz, Professor Malcolm Hopwood, Dr Bill Lyndon, Professor Roger Mulder, Professor Greg Murray, Professor Richard Porter and Associate Professor Ajeet Singh.

INTERNATIONAL EXPERT ADVISORS

Professor Carlo Altamura, Dr Francesco Colom, Professor Mark George, Professor Guy Goodwin, Professor Roger McIntyre, Dr Roger Ng, Professor John O'Brien, Professor Harold Sackeim, Professor Jan Scott, Dr Nobuhiro Sugiyama, Professor Eduard Vieta, Professor Lakshmi Yatham.

AUSTRALIAN AND NEW ZEALAND EXPERT ADVISORS

Professor Marie-Paule Austin, Professor Michael Berk, Dr Yulisha Byrow, Professor Helen Christensen, Dr Nick De Felice, A/Professor Seetal Dodd, A/Professor Megan Galbally, Dr Josh Geffen, Professor Philip Hazell, A/Professor David Horgan, A/Professor Felice Jacka, Professor Gordon Johnson, Professor Anthony Jorm, Dr Jon-Paul Khoo, Professor Jayashri Kulkarni, Dr Cameron Lacey, Dr Noeline Latt, Professor Florence Levy, A/Professor Andrew Lewis, Professor Colleen Loo, Dr Thomas Mayze, Dr Linton Meagher, Professor Philip Mitchell, Professor Daniel O'Connor, Dr Nick O'Connor, Dr Tim Outhred, Dr Mark Rowe, Dr Narelle Shadbolt, Dr Martien Snellen, Professor John Tiller, Dr Bill Watkins, Dr Raymond Wu.

[Actigraphy in Bipolar Disorder and First Degree Relatives]

BACKGROUND

Bipolar disorder is a disabling disease that involves a significant economic costs to the health system, making it is essential to investigate possible early predictors such as changes in sleep-wake cycle in high-risk populations.

OBJECTIVE

To review the available literature on alterations in the sleep-wake cycle and circadian rhythm in patients with bipolar disorder and their first degree relatives.

METHODS

A literature search was performed in the data bases, Access Medicine, ClinicalKey, EMBASE, JAMA, Lilacs, OVID, Oxford Journals, ScienceDirect, SciELO, APA y PsycNET. Articles in both English and Spanish were reviewed, without limits by study type.

RESULTS

Actigraphy is a non-invasive, useful method for assessing sleep-wake cycle disturbances in the active phases of bipolar disorder, and during euthymia periods. Actigraphy showed good sensitivity to predict true sleep, but low specificity, compared with polysomnography. Although studies in bipolar offspring and relatives are scarce, they show sleep changes similar to bipolar patients.

CONCLUSIONS

Actigraphy may be a good screening tool of sleep/wake cycle in patients with bipolar disorders, because it is economic, non-invasive and sensitive. Longitudinal studies are required to evaluate its potential use as a risk marker.

Biological rhythms in bipolar and depressive disorders: A community study with drug-naïve young adults

AIM

To assess biological rhythm disruptions among drug-naïve young adults with bipolar disorder (BD), major depressive disorder (MDD), and community controls.

METHODS

This was a cross-sectional study nested in a population-based study. BD and MDD were diagnosed using the Structured Clinical Interview for DSM-IV. Biological rhythm disruptions were assessed using the Biological Rhythm Interview of Assessment in Neuropsychiatry (BRIAN).

RESULTS

Two hundred seventeen subjects were assessed (49 BD, 74 MDD, and 94 community controls). Biological rhythm disruption was higher in subjects with BD (40.32±9.92; p<0.001) and MDD (36.23±8.71; p<0.001) than community controls (27.67±6.88). Subjects with BD had a higher BRIAN total score (p=0.028) and higher disruption in sleep/social domains (p=0.018) as compared to MDD. In addition, the BRIAN scores were higher in current MDD, euthymic BD, and BD in current episode group, as compared to community controls.

LIMITATION

Cross-sectional design. Absence of assessment of biomarkers of biological rhythms.

CONCLUSION

Bipolar disorder and major depressive disorder are associated with disruption in biological rhythm. In addition, disruption in sleep/social rhythms is higher in subjects with BD when compared to subjects with MDD. We also verified biological rhythm disruption in subjects with BD during euthymic status, but not in remitted MDD. Regulation of biological rhythm may be a means to identify patients with mood disorders and potentially differentiate MDD from BD.

Chronotype and Improved Sleep Efficiency Independently Predict Depressive Symptom Reduction after Group Cognitive Behavioral Therapy for Insomnia

STUDY OBJECTIVES

Cognitive behavioral therapy for insomnia (CBT-I) has been shown to improve both sleep and depressive symptoms, but predictors of depression outcome following CBT-I have not been well examined. This study investigated how chronotype (i.e., morningness-eveningness trait) and changes in sleep efficiency (SE) were related to changes in depressive symptoms among recipients of CBT-I.

METHODS

Included were 419 adult insomnia outpatients from a sleep disorders clinic (43.20% males, age mean ± standard deviation = 48.14 ± 14.02). All participants completed the Composite Scale of Morningness and attended at least 4 sessions of a 6-session group CBT-I. SE was extracted from sleep diary; depressive symptoms were assessed using the Beck Depression Inventory (BDI) prior to (Baseline), and at the end (End) of intervention.

RESULTS

Multilevel structural equation modeling revealed that from Baseline to End, SE increased and BDI decreased significantly. Controlling for age, sex, BDI, and SE at Baseline, stronger evening chronotype and less improvement in SE significantly and uniquely predicted less reduction in BDI from Baseline to End. Chronotype did not predict improvement in SE.

CONCLUSIONS

In an insomnia outpatient sample, SE and depressive symptoms improved significantly after a CBT-I group intervention. All chronotypes benefited from sleep improvement, but those with greater eveningness and/or less sleep improvement experienced less reduction in depressive symptom severity. This suggests that evening preference and insomnia symptoms may have distinct relationships with mood, raising the possibility that the effect of CBT-I on depressive symptoms could be enhanced by assessing and addressing circadian factors.

Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society on the Recommended Amount of Sleep for a Healthy Adult: Methodology and Discussion

The American Academy of Sleep Medicine and Sleep Research Society recently released a Consensus Statement regarding the recommended amount of sleep to promote optimal health in adults. This paper describes the methodology, background literature, voting process, and voting results for the consensus statement. In addition, we address important assumptions and challenges encountered during the consensus process. Finally, we outline future directions that will advance our understanding of sleep need and place sleep duration in the broader context of sleep health.

Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society on the Recommended Amount of Sleep for a Healthy Adult: Methodology and Discussion

The American Academy of Sleep Medicine and Sleep Research Society recently released a Consensus Statement regarding the recommended amount of sleep to promote optimal health in adults. This paper describes the methodology, background literature, voting process, and voting results for the consensus statement. In addition, we address important assumptions and challenges encountered during the consensus process. Finally, we outline future directions that will advance our understanding of sleep need and place sleep duration in the broader context of sleep health.

Indirect associations of combat exposure with post-deployment physical symptoms in U.S. soldiers: roles of post-traumatic stress disorder, depression and insomnia

OBJECTIVE

To characterize the indirect associations of combat exposure with post-deployment physical symptoms through shared associations with post-traumatic stress disorder (PTSD), depression and insomnia symptoms.

METHODS

Surveys were administered to a sample of U.S. soldiers (N = 587) three months after a 15-month deployment to Iraq. A multiple indirect effects model was used to characterize direct and indirect associations between combat exposure and physical symptoms.

RESULTS

Despite a zero-order correlation between combat exposure and physical symptoms, the multiple indirect effects analysis did not provide evidence of a direct association between these variables. Evidence for a significant indirect association of combat exposure and physical symptoms was observed through PTSD, depression, and insomnia symptoms. In fact, 92% of the total effect of combat exposure on physical symptoms scores was indirect. These findings were evident even after adjusting for the physical injury and relevant demographics.

CONCLUSION

This is the first empirical study to suggest that PTSD, depression and insomnia collectively and independently contribute to the association between combat exposure and post-deployment physical symptoms. Limitations, future research directions, and potential policy implications are discussed.

Investigating the mechanism(s) underlying switching between states in bipolar disorder

Bipolar disorder (BD) is a unique disorder that transcends domains of function since the same patient can exhibit depression or mania, states with polar opposite mood symptoms. During depression, people feel helplessness, reduced energy, and risk aversion, while with mania behaviors include grandiosity, increased energy, less sleep, and risk preference. The neural mechanism(s) underlying each state are gaining clarity, with catecholaminergic disruption seen during mania, and cholinergic dysfunction during depression. The fact that the same patient cycles/switches between these states is the defining characteristic of BD however. Of greater importance therefore, is the mechanism(s) underlying cycling from one state - and its associated neural changes - to another, considered the 'holy grail' of BD research. Herein, we review studies investigating triggers that induce switching to these states. By identifying such triggers, researchers can study neural mechanisms underlying each state and importantly how such mechanistic changes can occur in the same subject. Current animal models of this switch are also discussed, from submissive- and dominant-behaviors to kindling effects. Focus however, is placed on how seasonal changes can induce manic and depressive states in BD sufferers. Importantly, changing photoperiod lengths can induce local switches in neurotransmitter expression in normal animals, from increased catecholaminergic expression during periods of high activity, to increased somatostatin and corticotrophin releasing factor during periods of low activity. Identifying susceptibilities to this switch would enable the development of targeted animal models. From animal models, targeted treatments could be developed and tested that would minimize the likelihood of switching.

An Initial Investigation of the Relationship Between Insomnia and Hoarding

OBJECTIVE

Insomnia has been shown to have profound negative consequences on multiple aspects of daily functioning. Despite increased interest in the association between insomnia and psychopathology, no research has examined the relationships between insomnia and hoarding. The aim of the current investigation was to examine the associations between insomnia and hoarding severity.

METHODS

Participants consisted of patients with hoarding disorder (n = 24).

RESULTS

Results revealed that insomnia was a significant predictor of increased hoarding severity. In addition, when examining the relationships among insomnia and specific hoarding symptoms, sleep difficulties were associated with increased acquiring and difficulty discarding behaviors.

CONCLUSIONS

These findings add to a growing body of literature on insomnia and various forms of psychopathology, as well as research on symptoms related to hoarding. Reducing insomnia symptoms among hoarders may help to reduce hoarding-related behaviors and increase treatment efficacy.

Discrimination and sleep: a systematic review

An increasing body of literature indicates that discrimination has a negative impact on health; poor sleep may be an underlying mechanism. The primary objective of this review was to examine existing studies on the relationship between discrimination and sleep to clarify (a) the potential role of discrimination in shaping population patterns of sleep and sleep disparities, and (b) the research needed to develop interventions at individual and institutional levels. We identified articles from English-language publications in PubMed and EBSCO databases from inception through July 2014. We employed a broad definition of discrimination to include any form of unfair treatment and all self-reported and objectively assessed sleep outcomes, including duration, difficulties, and sleep architecture. Seventeen studies were identified: four prospective, 12 cross-sectional, and one that utilized a daily-diary design. Fifteen of the 17 studies evaluated interpersonal discrimination as the exposure and the majority of studies included self-reported sleep as the outcome. Only four studies incorporated objective sleep assessments. All 17 studies identified at least one association between discrimination and a measure of poorer sleep, although studies with more detailed consideration of either discrimination or sleep architecture revealed some inconsistencies. Taken together, existing studies demonstrate consistent evidence that discrimination is associated with poorer sleep outcomes. This evidence base can be strengthened with additional prospective studies that incorporate objectively measured aspects of sleep. We outline important extensions for this field of inquiry that can inform the development of interventions to improve sleep outcomes, and consequently promote well-being and reduce health inequities across the life course.

Sleep, arousal, and circadian rhythms in adults with obsessive-compulsive disorder: a meta-analysis

Findings of this meta-analysis show that obsessive-compulsive disorder (OCD) is related to disruptions in both the duration and timing of sleep. PsycINFO and Google Scholar database searches identified 12 relevant studies that compared measures of sleep in individuals with OCD to those of either a healthy control group or published norms. Sleep measures included sleep onset latency, sleep duration, awakening after sleep onset, percentage of rapid eye movement (REM) sleep, percentage of slow wave sleep, and prevalence of delayed sleep phase disorder (DSPD). Individual effect sizes were pooled using a random effects model. Sleep duration was found to be shorter, and the prevalence of DSPD higher, in individuals with OCD compared to controls. Further, excluding samples with comorbid depression did not meaningfully reduce the magnitude of these effects (although the results were no longer statistically significant) and medication use by participants is unlikely to have systematically altered sleep timing. Overall, available data suggest that sleep disruption is associated with OCD but further research on both sleep duration and sleep timing in individuals with OCD is needed.

CRY1 Variations Impacts on the Depressive Relapse Rate in a Sample of Bipolar Patients

OBJECTIVE

A relevant part of the social and personal burden caused by Bipolar Disorder (BD) is related to depressive phases. Authors investigated the genetic impact of a set of variations located in CRY1, a gene involved in the control of the circadian rhythms, towards depressive episodes in a sample of bipolar patients from the STEP-BD sample. As a secondary analysis, CYR1 variations were analyzed as predictors of sleep disruption.

METHODS

654 bipolar patients were included in the analysis. Data were available genome-wide. The part of the genome coding for the CRY1 was imputed and pruned according to standards in the field. 7 SNPs were available for the analysis. A correction for multitesting was applied and we had sufficient power (0.80) to detect a small-medium effect size (0.22) between two allelic frequencies each one represented by at least 300 subjects.

RESULTS

Intronic rs10861688 was associated with the number of depressive events corrected for the times patients were assessed during the period of observation. In particular, AA subjects (n=21) had 4.46±3.15 events, AG (n=141) had 3.08±3.17 and GG (n=342) 2.65±2.97 (p=0.0048, beta=-0.22). No other significant associations were reported.

CONCLUSION

We bring further evidence that genes involved in the regulation of circadian rhythms may be relevant to depressive bipolar phases. Independent confirmation analyses are mandatory.

A Retrospective Examination of Sleep Disturbance across the Course of Bipolar Disorder

Background

Sleep disturbance is a prevalent and clinically significant feature of bipolar disorder. However, there are aspects of sleep and bipolar disorder that have been minimally characterized. This study aims to fill several gaps in the literature by examining the prevalence, coexistence, and persistence of sleep disturbance retrospectively across a five-year period in bipolar disorder.

Methods

Fifty-one people with bipolar disorder I and comorbid insomnia who were currently inter-episode completed the NIMH Retrospective Life-Charting Methodology (the life chart). The life chart was used to document the prevalence, coexistence, and persistence of insomnia, hypersomnia, delayed sleep phase, reduced sleep need, and irregular sleep patterns across the course of five years.

Results

Across the five year period, manic months were primarily characterized by reduced sleep need (62.8%) and insomnia (38.1%), depressive months by hypersomnia (56.0%) and insomnia (51.9%), mixed months by all five types of sleep disturbance, and inter-episode months by insomnia (67.4%). There was coexistence in the types of sleep disturbance experienced. Further, each type of sleep disturbance demonstrated persistence across the five years, with persistence rates being the highest for insomnia (49.0–58.8%).

Conclusions

Sleep disturbance is a prevalent and complex feature across mood episodes and inter-episode periods of bipolar disorder. Further, there is variation in the types of sleep disturbance experienced.

Short-term effects of electroconvulsive therapy on subjective and actigraphy-assessed sleep parameters in severely depressed inpatients

Background. Sleep disturbances are a key feature of major depression. Electroconvulsive treatment (ECT) may improve polysomnography-assessed sleep characteristics, but its short-term effects on actigraphy-assessed and subjective sleep characteristics are unknown. We therefore aimed to assess the effects of ECT on subjective and objective sleep parameters in a proof-of-principle study. Methods. We assessed subjective and objective sleep parameters in 12 severely depressed patients up to 5 consecutive days during their ECT course, corresponding to a total of 43 nights (including 19 ECT sessions). The 12 patients were 83% female and on average 62 (standard deviation (SD) 14) years old and had an average MADRS score of 40 at baseline (SD 21). Results. Subjective and objective sleep parameters were not directly affected by ECT. The subjective sleep efficiency parameter was similar on the day after ECT and other days. ECT did not affect the number of errors in the Sustained Attention to Response Task. Patients subjectively underestimated their total sleep time by 1.4 hours (P < 0.001) compared to actigraphy-assessed sleep duration. Conclusion. ECT did not affect subjective and actigraphy-assessed sleep in the short term. Depressed patients profoundly underestimated their sleep duration.

Insomnia before and after treatment for anxiety and depression

BACKGROUND

Insomnia increases the likelihood of developing a mood or anxiety disorder. Moreover, symptoms of anxiety and depression, such as worry and rumination, contribute to insomnia. Given these relationships, there is a need to delineate how these disorders respond to treatment when they are comorbid.

METHODS

266 individuals presenting for anxiety and/or depression symptoms participated in this study in which symptoms of insomnia, anxiety, depression, disability, and sleep length were assessed. 102 of these patients were treated with internet-based cognitive behavioral therapy (iCBT) for anxiety and/or depression and 61 completed the treatment. Pre- to post-treatment symptom changes were examined in this subset.

RESULTS

Insomnia, as measured by the Insomnia Severity Index, was evident in 40% of the patients. Individuals with insomnia reported more severe symptoms of anxiety and depression than individuals without insomnia. iCBT focused on anxiety and/or depression was associated with reductions in symptoms of insomnia, anxiety, depression, and disability. Total sleep time did not change over treatment.

LIMITATIONS

As the data were collected in routine care, there was no control group and no longer term follow-up assessment.

CONCLUSIONS

These findings highlight the importance of insomnia across anxiety and depressive disorders. They further demonstrate that treatment for anxiety and/or depression appears to improve comorbid insomnia symptoms, though may be ineffective in changing sleep duration.

The role of lateral habenula-dorsal raphe nucleus circuits in higher brain functions and psychiatric illness

Serotonergic neurons in the dorsal raphe nucleus (DRN) play an important role in regulation of many physiological functions. The lateral nucleus of the habenular complex (LHb) is closely connected to the DRN both morphologically and functionally. The LHb is a key regulator of the activity of DRN serotonergic neurons, and it also receives reciprocal input from the DRN. The LHb is also a major way-station that receives limbic system input via the stria medullaris and provides output to the DRN and thereby indirectly connects a number of other brain regions to the DRN. The complex interactions of the LHb and DRN contribute to the regulation of numerous important behavioral and physiological mechanisms, including those regulating cognition, reward, pain sensitivity and patterns of sleep and waking. Disruption of these functions is characteristic of major psychiatric illnesses, so there has been a great deal of interest in how disturbed LHb-DRN interactions may contribute to the symptoms of these illnesses. This review summarizes recent research related to the roles of the LHb-DRN system in regulation of higher brain functions and the possible role of disturbed LHb-DRN function in the pathogenesis of psychiatric disorders, especially depression.

Borderline personality pathology and insomnia symptoms in community-dwelling older adults

Prior research has associated BPD with sleep problems, but the relationship has been explored primarily in small clinical samples of younger adults. Findings from our lab have demonstrated that borderline symptoms remain present in later middle age and are associated with several negative life outcomes. A representative community sample of older adults (N = 633, Mage  = 62.3) was obtained from the St Louis area, and interviewer-reports, self-reports, and informant-reports of personality pathology were completed along with an insomnia symptoms questionnaire. Cross-sectional analyses revealed that symptoms from all 10 DSM-IV personality disorders were significantly correlated with insomnia symptoms. However, after statistically controlling for major depression, body-mass index, race and gender, only borderline personality pathology remained significantly associated with insomnia symptoms. Our results demonstrate that in addition to other negative health outcomes, borderline personality pathology is uniquely associated with sleep problems in later middle-aged adults in the community.

Telemonitoring with respect to mood disorders and information and communication technologies: overview and presentation of the PSYCHE project

This paper reviews what we know about prediction in relation to mood disorders from the perspective of clinical, biological, and physiological markers. It then also presents how information and communication technologies have developed in the field of mood disorders, from the first steps, for example, the transition from paper and pencil to more sophisticated methods, to the development of ecological momentary assessment methods and, more recently, wearable systems. These recent developments have paved the way for the use of integrative approaches capable of assessing multiple variables. The PSYCHE project stands for Personalised monitoring SYstems for Care in mental HEalth.

Validation of the Italian Version of the Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN): Some Considerations on its Screening Usefulness

Introduction:

Abnormalities in biological rhythms (BR) may have a role in the pathophysiology of Bipolar Disorders (BD). The objective of this study is to validate the Italian version of the Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN), a useful tool in studying BR, and measure its accuracy in discriminating BD.

Methods:

44 outpatients with DSM-IV-TR diagnosis of BD and 38 controls balanced for sex and age were consecutively recruited. The discriminant validity of BRIAN for the screening of BD and its test re-test reliability in two evaluations were assessed.

Results:

BD patients scored 22.22±11.19 in BRIAN against 7.13±5.6 of the control group (P<0.0001). BRIAN showed a good accuracy to screen between BD non-BD at cutoff 16, a sensitivity was 68.2 and specificity was 92.5. The test-retest stability measured using Pearson’s coefficient found very high r values for each section and the total score, thus indicating a correlation at the two times of statistical significance in all measures. Cohen’s Kappa varied from 0.47 in the sociality section to 0.80 in the sleep section, with a total K mean of 0.65.

Conclusion:

The results show that the Italian version of BRIAN has good discriminant validity in detecting BD from healthy controls and shows good test-retest reliability. The study suggests the possibility of developing mixed screening tools by introducing items on dysregulation of biological rhythms to the usual measures of mood.

Circadian rhythms have broad implications for understanding brain and behavior

Circadian rhythms are generated by an endogenously organized timing system that drives daily rhythms in behavior, physiology and metabolism. In mammals, the suprachiasmatic nucleus (SCN) of the hypothalamus is the locus of a master circadian clock. The SCN is synchronized to environmental changes in the light:dark cycle by direct, monosynaptic innervation via the retino-hypothalamic tract. In turn, the SCN coordinates the rhythmic activities of innumerable subordinate clocks in virtually all bodily tissues and organs. The core molecular clockwork is composed of a transcriptional/post-translational feedback loop in which clock genes and their protein products periodically suppress their own transcription. This primary loop connects to downstream output genes by additional, interlocked transcriptional feedback loops to create tissue-specific 'circadian transcriptomes'. Signals from peripheral tissues inform the SCN of the internal state of the organism and the brain's master clock is modified accordingly. A consequence of this hierarchical, multilevel feedback system is that there are ubiquitous effects of circadian timing on genetic and metabolic responses throughout the body. This overview examines landmark studies in the history of the study of circadian timing system, and highlights our current understanding of the operation of circadian clocks with a focus on topics of interest to the neuroscience community.

An important role for cholecystokinin, a CLOCK target gene, in the development and treatment of manic-like behaviors

Mice with a mutation in the Clock gene (ClockΔ19) have been identified as a model of mania; however, the mechanisms that underlie this phenotype, and the changes in the brain that are necessary for lithium's effectiveness on these mice remain unclear. Here, we find that cholecystokinin (Cck) is a direct transcriptional target of CLOCK and levels of Cck are reduced in the ventral tegmental area (VTA) of ClockΔ19 mice. Selective knockdown of Cck expression via RNA interference in the VTA of wild-type mice produces a manic-like phenotype. Moreover, chronic treatment with lithium restores Cck expression to near wild-type and this increase is necessary for the therapeutic actions of lithium. The decrease in Cck expression in the ClockΔ19 mice appears to be due to a lack of interaction with the histone methyltransferase, MLL1, resulting in decreased histone H3K4me3 and gene transcription, an effect reversed by lithium. Human postmortem tissue from bipolar subjects reveals a similar increase in Cck expression in the VTA with mood stabilizer treatment. These studies identify a key role for Cck in the development and treatment of mania, and describe some of the molecular mechanisms by which lithium may act as an effective antimanic agent.

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

BACKGROUND

Psychiatry lags other fields in development of diagnostic tests.

METHODS

A literature review and meta-analysis was conducted to ascertain if polysomnographic abnormalities (REM density, REM latency, sleep efficiency, slow wave sleep, stage 1 and stage 2 sleep) warrant additional effort to develop them into a clinical diagnostic test for major depressive disorder (MDD). The 31 publications meeting inclusion criteria were then classified into one of three progressive steps using guidelines for evaluating the clinical usefulness of a diagnostic test.

RESULTS

Most of the abnormalities found in MDD patients, when compared to healthy controls, occurred in the expected direction with moderate effect sizes but with substantial publication bias and heterogeneity. Eleven studies compared abnormalities in MDD to other psychiatric disorders (step 2a), and four studies provided data on the sensitivity or specificity of the findings in differentiating among the psychiatric disorders that frequently appear on the same differential diagnostic list as MDD (step 2b). No multicenter trial has been conducted prospectively to test the clinical utility of the diagnostic test (step 3).

LIMITATIONS

Only published articles in the English language were used.

CONCLUSIONS

Sleep studies for the detection of MDD appear replicable with a moderate effect size. However, additional step 1 studies are needed to define the sensitivity and specificity. The heterogeneity of sleep recording, scoring techniques, and MDD must also be addressed.

The role of sleep in emotional brain function

Rapidly emerging evidence continues to describe an intimate and causal relationship between sleep and emotional brain function. These findings are mirrored by long-standing clinical observations demonstrating that nearly all mood and anxiety disorders co-occur with one or more sleep abnormalities. This review aims to (a) provide a synthesis of recent findings describing the emotional brain and behavioral benefits triggered by sleep, and conversely, the detrimental impairments following a lack of sleep; (b) outline a proposed framework in which sleep, and specifically rapid-eye movement (REM) sleep, supports a process of affective brain homeostasis, optimally preparing the organism for next-day social and emotional functioning; and (c) describe how this hypothesized framework can explain the prevalent relationships between sleep and psychiatric disorders, with a particular focus on posttraumatic stress disorder and major depression.

Self-reported sleep disturbance is associated with elevated levels of PAI-1 in individuals with a recorded history of depressive symptoms

BACKGROUND

The majority of depressed individuals report insomnia. Self-reported symptoms of insomnia, in particular, more strongly predict adverse health effects than the actual measured sleep time. The physiological alterations in individuals with insomnia are complex, as both autonomic and endocrine dysfunctions are present. Plasminogen activator inhibitor (PAI)-1 is a stress-related acute-phase reactant that has also been suggested to regulate the circadian rhythm and sleep patterns. It has been suggested to contribute to both depressive symptoms and sleep disorders, although data on the relationships between these parameters are scarce.

OBJECTIVE

This study examined the role of self-reported sleep disturbance and its association with PAI-1 among individuals with a history of depressive symptoms.

METHODS

Differences in the serum levels of PAI-1 between two groups (group 1: moderate to very severe sleep disturbance, n=37; group 2: mild or no sleep disturbance, n = 90) were examined in a population-based sample of individuals with a recorded history of depressive symptoms.

RESULTS

Multivariate analysis controlling for potential confounding factors (age, sex, body mass index, depression severity) showed that each 1-unit increase in PAI-1 (μg/mL) increased the likelihood for belonging to the group with moderate to very severe sleep disturbance by 23% (OR = 1.23, C.I. 95% = 1.04-1.45, p = 0.016). This statistical significance remained after additional adjustments for regular smoking and the use of sleep or lipid-lowering medication.

CONCLUSION

Our observations may further clarify the physiological alterations related to sleep disturbance in depressive individuals. In the present study, self-reported sleep disturbance in individuals with a recorded history of depressive symptoms was associated with an elevation of PAI-1. This finding may illustrate the association of subjective sleep disturbance with sympathetic activation. Our study highlights the importance of effects of perceived sleep disturbance on individual homeostasis, and may provide potential directions for research on treatment options.

Mood disturbance after infection

OBJECTIVE

An aetiological link between acute infection and major depression has long been hypothesized, and is increasingly gaining recognition within contemporary literature. This review aims to examine the evidence for such a link, specifically between acute, self-limiting infection and major depression, and to summarize the current understanding of pathophysiological mechanisms underlying this link.

METHODS

Relevant articles were sourced via an online search of published literature from Embase, MEDLINE, PsycINFO and PubMed using a variety of search terms including mood disorder, depression, infection and inflammation. Additionally, a search for articles from the bibliographies of retrieved papers was conducted.

RESULTS

Findings from retrospective studies suggest an association between infection and subsequent mood disturbance, including major depression. This association has been confirmed by studies employing prospective observational or experimental challenge designs. The available evidence supports a multifactorial basis of vulnerability towards major depression in the context of acute infection. Genetic, neuroendocrine, autonomic and psychosocial factors may interact to potentiate the likelihood of a severe and prolonged depressive response to an immunological stressor in some individuals.

CONCLUSION

Mood disturbance is likely to have a host-protective role in the context of an acute sickness response to infection. However, this usually adaptive and reversible response may progress in some vulnerable individuals into a more sustained and severe pattern of behavioural and physiological changes of major depression. Further research is needed to delineate the factors that predispose, precipitate and perpetuate depression in the context of acute infective illness. Such insights will inform effective prevention and treatment strategies.

Circadian rhythms in liver physiology and liver diseases

In mammals, circadian rhythms function to coordinate a diverse panel of physiological processes with environmental conditions such as food and light. As the driving force for circadian rhythmicity, the molecular clock is a self-sustained transcription-translational feedback loop system consisting of transcription factors, epigenetic modulators, kinases/phosphatases, and ubiquitin E3 ligases. The molecular clock exists not only in the suprachiasmatic nuclei of the hypothalamus but also in the peripheral tissues to regulate cellular and physiological function in a tissue-specific manner. The circadian clock system in the liver plays important roles in regulating metabolism and energy homeostasis. Clock gene mutant animals display impaired glucose and lipid metabolism and are susceptible to diet-induced obesity and metabolic dysfunction, providing strong evidence for the connection between the circadian clock and metabolic homeostasis. Circadian-controlled hepatic metabolism is partially achieved by controlling the expression and/or activity of key metabolic enzymes, transcription factors, signaling molecules, and transporters. Reciprocally, intracellular metabolites modulate the molecular clock activity in response to the energy status. Although still at the early stage, circadian clock dysfunction has been implicated in common chronic liver diseases. Circadian dysregulation of lipid metabolism, detoxification, reactive oxygen species (ROS) production, and cell-cycle control might contribute to the onset and progression of liver steatosis, fibrosis, and even carcinogenesis. In summary, these findings call for a comprehensive study of the function and mechanisms of hepatic circadian clock to gain better understanding of liver physiology and diseases.

The role of beliefs and attitudes about sleep in seasonal and nonseasonal mood disorder, and nondepressed controls

BACKGROUND

Unhelpful sleep-related cognitions play an important role in insomnia and major depressive disorder, but their role in seasonal affective disorder has not yet been explored. Therefore, the purpose of this study was to determine if individuals with seasonal affective disorder (SAD) have sleep-related cognitions similar to those with primary insomnia, and those with insomnia related to comorbid nonseasonal depression.

METHODS

Participants (n=147) completed the Dysfunctional Beliefs and Attitudes about Sleep 16-item scale (DBAS-16) and the Structured Interview Guide for the Hamilton Depression Rating Scale, Seasonal Affective Disorder Version (SIGH-SAD), which assesses self reported sleep problems including early, middle, or late insomnia, and hypersomnia in the previous week. All participants were assessed in winter, and during an episode for those with a depressive disorder.

RESULTS

Individuals with SAD were more likely to report hypersomnia on the SIGH-SAD, as well as a combined presentation of hypersomnia and insomnia on the Pittsburgh Sleep Quality Index (PSQI). The SAD group reported DBAS-16 scores in the range associated with clinical sleep disturbance, and DBAS-16 scores were most strongly associated with reports of early insomnia, suggesting circadian misalignment.

LIMITATIONS

Limitations include the self-report nature of the SIGH-SAD instrument on which insomnia and hypersomnia reports were based.

CONCLUSIONS

Future work could employ sleep- or chronobiological-focused interventions to improve clinical response in SAD.

Objective and subjective socioeconomic gradients exist for sleep in children and adolescents

OBJECTIVE

Socioeconomic position (SEP) is inversely associated with many health outcomes, yielding a socioeconomic gradient in health. In adults, low SEP is associated with short sleep duration, poorer sleep quality, and difficulty initiating and maintaining sleep. Relatively little is known about this relation in youth. The aim of the present study was to examine whether socioeconomic gradients exist for various sleep indices among a healthy sample of children and adolescents.

METHOD

Participants took part in the larger Healthy Heart Project and included 239 youth (69.6% Caucasian; 45.6% female), aged 8-17 years (M = 12.6, SD = 1.9). Parental income and education were used to measure objective SEP. The Subjective Social Status Scale-Youth Version was used to measure subjective SEP. Sleep duration, sleep quality, daytime sleepiness, and sleep disturbances were assessed through self- and parent-report.

RESULTS

In children, objective SEP was related with sleep duration (β = .35, p < .01), although subjective SEP was related with daytime sleepiness (βavg = .33, p < .01) and parent-reported sleep duration (β = .23, p < .05). In adolescents, subjective SEP was related with sleep quality (β = .28, p < .01) and parent-reported sleep duration (β = -.18, p < .05), even after controlling for objective SEP.

CONCLUSIONS

Socioeconomic gradients were observed for multiple sleep measures in youth. Objective parental SEP was related with sleep complaints (e.g., sleep disturbances), and subjective SEP was related with sleep quality and daytime sleepiness. Findings suggest sleep may be one pathway underlying the socioeconomic gradient in health. Future research should aim to elucidate how distinct sleep constructs may explain how socioeconomic status "gets under the skin" to affect health.

Treatment of bipolar disorder

We review recent developments in the acute and long-term treatment of bipolar disorder and identify promising future routes to therapeutic innovation. Overall, advances in drug treatment remain quite modest. Antipsychotic drugs are effective in the acute treatment of mania; their efficacy in the treatment of depression is variable with the clearest evidence for quetiapine. Despite their widespread use, considerable uncertainty and controversy remains about the use of antidepressant drugs in the management of depressive episodes. Lithium has the strongest evidence for long-term relapse prevention; the evidence for anticonvulsants such as divalproex and lamotrigine is less robust and there is much uncertainty about the longer term benefits of antipsychotics. Substantial progress has been made in the development and assessment of adjunctive psychosocial interventions. Long-term maintenance and possibly acute stabilisation of depression can be enhanced by the combination of psychosocial treatments with drugs. The development of future treatments should consider both the neurobiological and psychosocial mechanisms underlying the disorder. We should continue to repurpose treatments and to recognise the role of serendipity. We should also investigate optimum combinations of pharmacological and psychotherapeutic treatments at different stages of the illness. Clarification of the mechanisms by which different treatments affect sleep and circadian rhythms and their relation with daily mood fluctuations is likely to help with the treatment selection for individual patients. To be economically viable, existing psychotherapy protocols need to be made briefer and more efficient for improved scalability and sustainability in widespread implementation.

REM sleep dysregulation in depression: state of the art

Disturbances of sleep are typical for most depressed patients and belong to the core symptoms of the disorder. Since the 1960s polysomnographic sleep research has demonstrated that besides disturbances of sleep continuity, depression is associated with altered sleep architecture, i.e., a decrease in slow wave sleep (SWS) production and disturbed rapid eye movement (REM) sleep regulation. Shortened REM latency (i.e., the interval between sleep onset and the occurrence of the first REM period), increased REM sleep duration and increased REM density (i.e., the frequency of rapid eye movements per REM period) have been considered as biological markers of depression which might predict relapse and recurrence. High risk studies including healthy relatives of patients with depression demonstrate that REM sleep alterations may precede the clinical expression of depression and may thus be useful in identifying subjects at high risk for the illness. Several models have been developed to explain REM sleep abnormalities in depression, like the cholinergic-aminergic imbalance model or chronobiologically inspired theories, which are reviewed in this overview. Moreover, REM sleep alterations have been recently considered not only as biological "scars" but as true endophenotypes of depression. This review discusses the genetic, neurochemical and neurobiological factors that have been implicated to play a role in the complex relationships between REM sleep and depression. We hypothesize on the one hand that REM sleep dysregulation in depression may be linked to a genetic predisposition/vulnerability to develop the illness; on the other hand it is conceivable that REM sleep disinhibition in itself is a part of a maladaptive stress reaction with increased allostatic load. We also discuss whether the REM sleep changes in depression may contribute themselves to the development of central symptoms of depression such as cognitive distortions including negative self-esteem and the overnight consolidation of negatively toned emotional memories.

Objective and subjective sleep disturbances in individuals with psychiatric disabilities

Sleep disturbances are common complaints in individuals with psychiatric disabilities, frequently occurring at onset and with exacerbation of illness. A small descriptive study of community-based overweight individuals (N = 9) completed the Pittsburgh Sleep Quality Index, wore an ActiGraph and kept a sleep diary for 7 to 14 days. All but two participants had poor sleep efficiency based on actigraphy scores, an objective measure of sleep. These scores were in agreement with the Pittsburgh Sleep Quality Index, a self-report measure, in all but one participant. The findings indicate the Pittsburgh Sleep Quality Index is a comprehensive measure to use in assessing sleep in individuals who have psychiatric disabilities.

Effects of quetiapine extended release on sleep and quality of life in midlife women with major depressive disorder

Depression during midlife years may lead to significant sleep disturbances and adversely impact quality of life (QOL). In this report, we examined the effects of treatment with quetiapine extended release (XR), 150-300 mg/day, on sleep and QOL in 23 midlife women with major depressive disorder (MDD). Quetiapine XR improved subjective sleep distress, overall sleep parameters, and sleep-related QOL, ultimately leading to significant improvement in menopause-related QOL. While larger, controlled trials are still awaited, these preliminary results are encouraging and suggest that quetiapine XR may be a useful tool in treating symptomatic midlife women with MDD.

Sleep disturbance in mental health problems and neurodegenerative disease

Sleep has been described as being of the brain, by the brain, and for the brain. This fundamental neurobiological behavior is controlled by homeostatic and circadian (24-hour) processes and is vital for normal brain function. This review will outline the normal sleep-wake cycle, the changes that occur during aging, and the specific patterns of sleep disturbance that occur in association with both mental health disorders and neurodegenerative disorders. The role of primary sleep disorders such as insomnia, obstructive sleep apnea, and REM sleep behavior disorder as potential causes or risk factors for particular mental health or neurodegenerative problems will also be discussed.

The effects of combining serotonin reuptake inhibition and 5-HT7 receptor blockade on circadian rhythm regulation in rodents

Disruption of circadian rhythms may lead to mood disorders. The present study investigated the potential therapeutic utility of combining a 5-HT7 antagonist with a selective serotonin (5-HT) reuptake inhibitor (SSRI), the standard of care in depression, on circadian rhythm regulation. In tissue explants of the suprachiasmatic nucleus (SCN) from PER2::LUC mice genetically modified to report changes in the expression of a key clock protein, the period length of PER2 bioluminescence was shortened in the presence of AS19, a 5-HT7 partial agonist. This reduction was blocked by SB269970, a selective 5-HT7 antagonist. The SSRI, escitalopram, had no effect alone on period length, but a combination with SB269970, yielded significant increases. Dosed in vivo, escitalopram had little impact on the occurrence of activity onsets in rats given access to running wheels, whether the drug was given acutely or sub-chronically. However, preceding the escitalopram treatment with a single acute dose of SB269970 produced robust phase delays, in keeping with the in vitro explant data. Taken together, these findings suggest that the combination of an SSRI and a 5-HT7 receptor antagonist has a greater impact on circadian rhythms than that observed with either agent alone, and that such a multimodal approach may be of therapeutic value in treating patients with poor clock function.

Modeling the direction of causation between cross-sectional measures of disrupted sleep, anxiety and depression in a sample of male and female Australian twins

The direction of causation between measures of disrupted sleep, anxiety and depression is not well understood. Under certain conditions, cross-sectional analysis based on genetically informative data can provide important information about the direction of causation between variables. Two community-based samples of 7235 Australian twins aged 18-87 years were mailed an extensive questionnaire that covered a wide range of personality and behavioral measures. Included were self-report measures of disrupted sleep, as well as symptoms of anxiety and depression. Among all females, modeling the direction of causation did not support the hypothesis of sleep having a direct causal impact on risk of anxiety or depression. Among older females, we found evidence that both anxiety and depression interact reciprocally with disrupted sleep, whereas among younger women both anxiety and depression appear to have a causal impact on sleep. Results for males were equivocal. The nosological implications of our findings are discussed.

Integrative physiology of depression and antidepressant drug action: implications for serotonergic mechanisms of action and novel therapeutic strategies for treatment of depression

Major depressive disorder (MDD) is predicted to be the second leading cause of disability worldwide by the year 2020. Currently available treatments for MDD are suboptimal. Only 50% of MDD patients recover in less than 12 weeks with adequate treatment, and up to 20% of patients will fail to adequately respond to all currently available interventions. Moreover, current treatments come at the cost of significant central nervous system (CNS) side effects, further highlighting the need for more effective treatments with fewer side effects. A greater mechanistic understanding of MDD and the actions of antidepressant drugs would provide opportunities for development of novel therapeutic approaches to treatment. With this aim in mind, we explore the novel, but empirically supported, hypothesis that an evolutionarily ancient thermoafferent pathway, signaling via the spinoparabrachial pathway from serotonergic sensory cells in the skin and other epithelial linings to serotonergic neurons and depression-related circuits in the brain, is dysfunctional in MDD and that antidepressant therapies, including antidepressant drugs and exercise, act by restoring its function.

An evaluation of polymorphisms in casein kinase 1 delta and epsilon genes in major psychiatric disorders

Disturbances of the circadian rhythm are involved in the pathophysiology of bipolar disorder (BD), schizophrenia (SCZ) and major depressive disorder (MDD). Specifically, because clock gene dysfunction is good candidate for enhancing the susceptibility to these psychiatric disorders, we selected two circadian rhythm-related genes (CSNK1D and CSNK1E) and investigated genetic associations of the genes with these three disorders. None of the SNPs showed a significant association with MDD, but a SNP (rs2075984) in CSNK1E and SNP (rs6502097) in CSNK1D were associated with SCZ (P=0.0091, uncorrected) and BD (P=0.030, uncorrected), respectively. To confirm these findings, we analyzed an independent dataset (maximum N=3815) but found a lack of association (P=0.63 for rs2075984 and P=0.61 for rs6502097). The final meta-analysis showed no association between these SNPs with SCZ (P=0.21) and BD (P=0.53). These results do not support that genetic variation in CSNK1D and CSNK1E is a susceptibility factor for major psychiatric disorders in the Japanese population.

Bright light therapy in the treatment of childhood and adolescence depression, antepartum depression, and eating disorders

Circadian rhythm disorders represent an important component underlying the pathology of depression. One of the subtypes of depression, in which these disorders may play a crucial role, is the seasonal affective disorder (SAD). The bright light therapy (BLT) has been reported as a novel, promising treatment method for SAD since 1984, and most of the data revealing its efficacy has been referred to adult patients, without comorbid disorders. However, in the recent years, more and more reports have been presented, which confirm the usefulness of BLT in some specific subpopulations of patients, including children, adolescents and pregnant women. The present review summarizes the applications of BLT in antepartum depression, childhood and adolescence depression as well as in patients suffering from eating disorders. Although the body of evidence is still too small to recommend the use of BLT as the first line of treatment for the depression or eating disorders in these patient subpopulations; it appears that BLT may be a useful alternative or adjunctive therapy for these diseases. However, the specific clinical applications of BLT in these areas need further investigation.

Neuroimmunomodulation in unipolar depression: a focus on chronobiology and chronotherapeutics

The rising burden of unipolar depression along with its often related sleep disturbances, as well as increasing rates of sleep restriction in modern society, make the search for an extended understanding of the aetiology and pathophysiology of depression necessary. Accumulating evidence suggests an important role for the immune system in mediating disrupted neurobiological and chronobiological processes in depression. This review aims to provide an overview of the neuroimmunomodulatory processes involved with depression and antidepressant treatments with a special focus on chronobiology, chronotherapeutics and the emerging field of immune-circadian bi-directional crosstalk. Increasing evidence suggests that chronobiological disruption can mediate immune changes in depression, and likewise, immune processes can mediate chronobiological disruption. This may suggest a bi-directional relationship in immune-circadian crosstalk. Furthermore, given the immunomodulatory effects of antidepressants and chronotherapeutics, as well as their associated beneficial effects on circadian disturbance, we--and others--suggest that these therapeutic agents may exert their chronobiotic effects partially via the neuroimmune system. Further research is required to better elucidate the mechanisms of immune involvement in the chronobiology of depression.