Chronobiology and Chronotherapy of Affective Disorders

Circadian rhythms are recurring cycles across a range of behavioural, physiological and cognitive domains that display periods of approximately twenty four hours and are generated by an endogenous circadian timing system. In this review we examine the evidence that circadian rhythms are disrupted in affective disorders such as major depression, bipolar disorder and seasonal affective disorder, and examine what the nature of such circadian dysfunction may be. Further, we examine the evidence that chronotherapeutic interventions (both behavioural and pharmacological) that address underlying abnormalities of circadian phase in patients with affective disorders may produce rapid onset and long-lasting symptom relief. We conclude that there is promising data in the literature to support the utility of drawing on a considerable body of neuroscientific knowledge of circadian clock fundamentals to design and implement chronotherapeutic interventions in major affective disorders, but that there is also a need for a more systematic approach involving larger scale studies

Editorial: Special Issue: circadian rhythms, clock genes and neuropsychiatry: interesting times

Circadian rhythms are cycles in physiological, behavioural, psychological and other domains that recur approximately every 24 h. Such rhythms are driven by an endogenous circadian timekeeping system, whose molecular basis consists of the interlocking transcription and translation of a panel of "clock" genes, the expression of which then regulates gene expression and cellular function in a tissuespecific manner. Such rhythmic expression of clock genes is observed in most tissues, including the master circadian pacemaker in the suprachiasmatic nucleus of the hypothalamus, other CNS sites and peripheral organs. Therefore, the circadian system exerts considerable control over physiology and behaviour, and equally dysfunction of this circadian system may result in detrimental pathophysiological and psychopathological consequences

Editorial: Special Issue: circadian rhythms, clock genes and neuropsychiatry: interesting times

Circadian rhythms are cycles in physiological, behavioural, psychological and other domains that recur approximately every 24 h. Such rhythms are driven by an endogenous circadian timekeeping system, whose molecular basis consists of the interlocking transcription and translation of a panel of "clock" genes, the expression of which then regulates gene expression and cellular function in a tissuespecific manner. Such rhythmic expression of clock genes is observed in most tissues, including the master circadian pacemaker in the suprachiasmatic nucleus of the hypothalamus, other CNS sites and peripheral organs. Therefore, the circadian system exerts considerable control over physiology and behaviour, and equally dysfunction of this circadian system may result in detrimental pathophysiological and psychopathological consequences

Sleep Beliefs, Subjective Sleep Quality and Diurnal Preference – Findings from Depressed Patients

This study evaluated the relationship between dysfunctional sleep beliefs, circadian typology and self-reported sleep quality and insomnia. We assessed these parameters both in healthy controls and patients with depression. One hundred eighty six subjects were assessed and completed measures of sleep beliefs, sleep disturbance, sleep quality, daytime sleepiness, depressive symptoms and circadian typology. We found that sleep beliefs are slightly linked with the subjective sleep quality, but with neither the diurnal preference, nor the self-reported insomnia

Self-Reported Diurnal Preference and Sleep Disturbance in Type 2 Diabetes Mellitus

Background. Previous sleep studies suggest that type 2 diabetes mellitus is associated with poor quality of sleep and sleep disorders. Aim. To evaluate sleep parameters and diurnal preference in type 2 diabetic patients, using a questionnaire. Methods. Ninety seven patients (aged 55.8±8.3, sex ratio 1:1), previously diagnosed with type 2 diabetes mellitus, together with 102 controls (aged 47.1±10.5, sex ratio 1:1), without diabetes, completed a questionnaire containing the Romanian translation of the Composite Scale of Morningness, the Sleep Disorders Questionnaire, the Pittsburgh Sleep Quality Index, the Pittsburgh Insomnia Rating Scale, the Multidimensional Fatigue Inventory, the Epworth Sleepiness Scale, the Alcohol Use Disorders Identification Test and the Beck Depression Inventory II (BDI). The study was cross-sectional, as we included subjects from outpatient and inpatient facilities. The recruitment process was based on handing invitation letters to patients consulting their physician, as well as to their acquaintances, using the snowball sampling. Participation was voluntary and anonymous

Effects of societal-level COVID-19 mitigation measures on the timing and quality of sleep in Ireland

Objectives Under usual circumstances, sleep timing is strongly influenced by societal imperatives. The sweeping whole-of-society measures introduced in response to the COVID-19 pandemic may represent a unique opportunity to examine the impact of large-scale changes in work practices on sleep timing. As such, we examined the impact of the travel restrictions and work from home orders imposed in Ireland in March 2020 on sleep timing and quality. Methods We utilized a cross-sectional survey deployed shortly after the imposition of restrictions which assessed current and retrospective ratings of sleep timing and quality; the final response set analysed was from 797 adults. Participants completed the ultra-short Munich Chronotype Questionnaire, the Pittsburg Sleep Quality Index, and answered questions pertaining to work status such as working from home during the period of restrictions. Results and conclusion There was a significant shift to later sleep start and end times, as well as delayed time of midsleep on both work and free days, during the period of restrictions. Sleep duration was longer for work days, while free day sleep duration was shorter and there was a reduction in social jetlag during the restrictions. Those who worked from home during restrictions had longer sleep duration on work day and had a significantly larger difference in sleep end on work day than “essential” workers who continued to attend their normal place of work

Sleep disturbances and circadian CLOCK genes in borderline personality disorder

Borderline personality disorder (BPD) is characterised by a deep-reaching pattern of affective instability, incoherent identity, self-injury, suicide attempts, and disturbed interpersonal relations and lifestyle. The daily activities of BPD patients are often chaotic and disorganized, with patients often staying up late while sleeping during the day. These behavioural patterns suggest that altered circadian rhythms may be associated with BPD. Furthermore, BPD patients frequently report suffering from sleep disturbances. In this review, we overview the evidence that circadian rhythms and sleep are disturbed in BPD, and we explore the possibility that personality traits that are pertinent for BPD may be associated with circadian typology, and perhaps to circadian genotypes. With regards to sleep architecture, we review the evidence that BPD patients display altered non-REM and REM sleep. A possible cue to a deeper understanding of this temporal dysregulation might be an analysis of the circadian clock at the molecular and cellular level, as well as behavioural studies using actigraphy and we suggest avenues for further exploration of these factors

A Data-Informed Perspective on Public Preferences for Retaining or Abolishing Biannual Clock Changes

Scientific, public, and political discourse around the perennial changing of the clocks during the transitions into and out of daylight saving time (DST) is a touchstone issue for the translation of fundamental chronobiology into societal impacts. The Society for Research on Biological Rhythms, along with other sleep science bodies, has issued a position statement that advocates for the abolition of the biannual clock changes and the adoption of permanent standard time for the optimization of population circadian health. However, there is a paucity of data on preexisting public perceptions and preferences with regard to these issues. In this perspective, we examine 5 issues that we believe are pertinent for chronobiologists to consider to enable effective advocacy on these policies; in particular, we discuss public preference for permanent DST and steps that may need to be taken to understand this preference. We inform our discussion with reference to cross-sectional studies we undertook in Spring 2020 and Fall 2019, around the transition out of and into DST Ireland. We conclude that there appears to be a gap between existing public perceptions and preferences around the clock changes and chronobiological and sleep science-informed positions, and that the chronobiology community may benefit from interdisciplinary collaboration with colleagues with specific social sciences expertise to most effectively advocate for these research-informed positions

ADHD 24/7:Circadian clock genes, chronotherapy and sleep/wake cycle insufficiencies in ADHD

Objectives: The current paper addresses the evidence for circadian clock characteristics associated with attention-deficit hyperactivity disorder (ADHD), and possible therapeutic approaches based on chronomodulation through bright light (BL) therapy. Methods: We review the data reported in ADHD on genetic risk factors for phase-delayed circadian rhythms and on the role of photic input in circadian re-alignment. Results: Single nucleotide polymorphisms in circadian genes were recently associated with core ADHD symptoms, increased evening-orientation and frequent sleep problems. Additionally, alterations in exposure and response to photic input may underlie circadian problems in ADHD. BL therapy was shown to be effective for re-alignment of circadian physiology toward morningness, reducing sleep disturbances and bringing overall improvement in ADHD symptoms. The susceptibility of the circadian system to phase shift by timed BL exposure may have broad cost-effective potential implications for the treatment of ADHD. Conclusions: We conclude that further research of circadian function in ADHD should focus on detection of genetic markers (e.g., using human skin fibroblasts) and development of BL-based therapeutic interventions