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Sleep and circadian rhythm problems intertwine with affective disorders. Adolescents are particularly vulnerable to developing sleep and affective problems. Yet, the temporal pathways between circadian rhythm, depression and anxiety in the transition phase from adolescence to early adulthood are not fully understood. 233 adolescents (76 % females) participated at two time points (T1 and T2) at an interval of 19-months (aged 16.8 and 18.4 years). We used The Beck Depression Inventory-II, Generalized Anxiety Disorder Assessment, GENEActiv actigraphy across 8 days (delayed sleep phase (DSP), sleep duration, midpoint, and regularity), and iButton 1922L thermologgers across 3 days (intrinsic circadian period length, amplitude, and mesor). A shorter sleep duration at T1 associated with an increase in affective problems at T2, and affective problems at T1 associated with an increase in sleep irregularity at T2. A longer circadian period at T1 associated with an increase in males' affective problems at T2. Moderate to severe depression and anxiety at T1 associated with a 2.69-fold risk (95 % CI 1.38–5.26, p = 0.004) and 2.11-fold risk (95 % CI 1.04–4.25, p = 0.038) of poor sleep quality at T2. Moderate to severe generalized anxiety associated with a 3.17-fold risk (95 % CI 1.35–7.41, p = 0.008) of DSP at T2. The follow-up period is short. The results revealed bidirectional temporal links between sleep and affective problems. Novel observations include a heightened risk of future DSP following a current anxiety disorder and a heightened risk of affective problems following a longer circadian period measured from the 24-hour temperature variation in males. • Temporal links between sleep and affective problems are bi-directional. • Transition to adulthood is influenced by sleep in adolescence. • Higher levels of anxiety increase the risk of delayed sleep phase. • Longer circadian period precedes affective problems in boys. [ABSTRACT FROM AUTHOR]

Abstract Background The coronavirus disease 2019 (COVID-19) pandemic has greatly changed our daily life. Owing to the imposed restrictions, many educational facilities have introduced remote teaching. This study aims to clarify the association between remote teaching and Japanese university students' sleeping habits. Methods The participants were medical students at Aichi Medical University. We used data from an ongoing longitudinal sleeping habits survey. For the participants who enrolled in the university during 2018–2020, multilevel analyses of sleep duration during weekdays and weekends across 3 years were conducted, adjusting for sex, grade, place of stay, sleep problems and lifestyle habits. Results Among the students enrolled in the university, the data of 677 in 2018, 657 in 2019, and 398 in 2020 was available for analysis. The mean sleep duration during weekdays (in minutes) was 407.6 ± 60.3 in 2018, 406.9 ± 63.0 in 2019, and 417.3 ± 80.9 in 2020. The mean sleep duration during weekends (in minutes) was 494.5 ± 82.5 in 2018, 488.3 ± 87.9 in 2019, and 462.3 ± 96.4 in 2020. Multilevel analysis conducted for the 684 participants who enrolled during 2018–2020 showed that sleep duration during weekdays was associated with the place of stay and survey year. Moreover, students reported significantly longer sleep duration during weekdays in 2020 than in 2019, but no significant difference in sleep duration was found between 2018 and 2019. The other multilevel analysis found sleep duration during weekends to be associated with the survey year, sex and always doing something before going to bed. Sleep duration during weekends was shorter in 2020 than in 2019 and longer for male students and students who always do something before going to bed. Ten students were reported to have a delayed sleep phase in 2020. Conclusions Students' sleep duration increased during weekdays and decreased during weekends in 2020. This difference could be explained by the COVID-19 pandemic and the introduction of remote teaching.

Reut Gruber,1,2 Liron Salamon,3 Riva Tauman,4 Michal Al-Yagon3 1Department of Psychiatry, McGill University, Montreal, QC, Canada; 2Attention, Behaviour and Sleep Lab, Douglas Mental Health University Institute, Montreal, QC, Canada; 3Department of School Counseling and Special Education, Tel-Aviv University, Tel-Aviv, Israel; 4Sleep Disorders Center, Tel Aviv Souraski Medical Center, Tel Aviv, IsraelCorrespondence: Reut Gruber, Department of Psychiatry, McGill University, Montreal, QC, Canada, Email Reut.Gruber@Douglas.Mcgill.CaIntroduction: Delayed sleep phase syndrome (DSPS) and insomnia disorders are prevalent in adolescents and are comorbid with attention-deficit/hyperactivity disorder (ADHD), but only limited information is available regarding the prevalence of DSPS and insomnia in adolescents with ADHD. Moreover, previous studies comparing objective sleep parameters averaged the findings across all participants of each group (ADHD, control) regardless of each individual’s level of reported sleep disturbance. This might have resulted in inconsistency between information obtained by objective and subjective sleep measures in adolescents with ADHD. The objectives of the present study were 1) to compare the prevalence of risk for DSPS and insomnia in adolescents with ADHD and control adolescents in our samples; 2) to compare objectively measured sleep characteristics of adolescents with ADHD and controls while taking into consideration their levels of risk for DSPS or their level of insomnia; and 3) to compare the ADHD symptom levels of adolescents with moderate/high and low risk for DSPS or insomnia.Methods: Seventy-three adolescents (37 ADHD, 36 controls) aged 12– 15 years participated in a cross-sectional study. Actigraphy was used to characterize objective sleep parameters and parents’ or adolescents’ reports were used to characterize subjective sleep parameters.Results: Of the participants in the ADHD and control groups, 33.33% and 27%, respectively, had moderate/high levels of risk for DSPS. Adolescents in the high-risk group for DSPS had an objectively measured delayed sleep schedule and more variable sleep duration, time in bed, and sleep efficiency compared to adolescents in the low-risk group for DSPS, regardless of their ADHD diagnosis. Adolescents with higher levels of insomnia spent more time in bed and had more variable sleep efficiency compared to adolescents with no insomnia, regardless of their diagnosis.Conclusion: The prevalence of moderate/high risk for DSPS was similarly high in adolescents with ADHD and controls. Participants’ subjective reports of sleep disturbances were consistent with their objective sleep parameters when the type and level of subjectively defined sleep disturbance were considered. ADHD symptom levels were not different in adolescents with moderate/high or low risk for DSPS or insomnia.Keywords: delayed sleep phase, insomnia, subjective sleep measures, actigraphy

Background: The coronavirus disease 2019 (COVID-19) pandemic has greatly changed our daily life. Owing to the imposed restrictions, many educational facilities have introduced remote teaching. This study aims to clarify the association between remote teaching and Japanese university students' sleeping habits. Methods: The participants were medical students at Aichi Medical University. We used data from an ongoing longitudinal sleeping habits survey. For the participants who enrolled in the university during 2018–2020, multilevel analyses of sleep duration during weekdays and weekends across 3 years were conducted, adjusting for sex, grade, place of stay, sleep problems and lifestyle habits. Results: Among the students enrolled in the university, the data of 677 in 2018, 657 in 2019, and 398 in 2020 was available for analysis. The mean sleep duration during weekdays (in minutes) was 407.6 ± 60.3 in 2018, 406.9 ± 63.0 in 2019, and 417.3 ± 80.9 in 2020. The mean sleep duration during weekends (in minutes) was 494.5 ± 82.5 in 2018, 488.3 ± 87.9 in 2019, and 462.3 ± 96.4 in 2020. Multilevel analysis conducted for the 684 participants who enrolled during 2018–2020 showed that sleep duration during weekdays was associated with the place of stay and survey year. Moreover, students reported significantly longer sleep duration during weekdays in 2020 than in 2019, but no significant difference in sleep duration was found between 2018 and 2019. The other multilevel analysis found sleep duration during weekends to be associated with the survey year, sex and always doing something before going to bed. Sleep duration during weekends was shorter in 2020 than in 2019 and longer for male students and students who always do something before going to bed. Ten students were reported to have a delayed sleep phase in 2020. Conclusions: Students' sleep duration increased during weekdays and decreased during weekends in 2020. This difference could be explained by the COVID-19 pandemic and the introduction of remote teaching. [ABSTRACT FROM AUTHOR]

Lenses that filter short-wavelength ("blue") light are commercially marketed to improve sleep and circadian health. Despite their widespread use, minimal data are available regarding their comparative efficacy in curtailing blue light exposure while maintaining visibility. Fifty commercial lenses were evaluated using five light sources: a blue LED array, a computer tablet display, an incandescent lamp, a fluorescent overhead luminaire, and sunlight. Absolute irradiance was measured at baseline and for each lens across the visual spectrum (380–780 nm), which allowed calculation of percent transmission. Transmission specificity was also calculated to determine whether light transmission was predominantly circadian-proficient (455–560 nm) or non-proficient (380–454 nm and 561–780 nm). Lenses were grouped by tint and metrics were compared between groups. Red-tinted lenses exhibited the lowest transmission of circadian-proficient light, while reflective blue lenses had the highest transmission. Orange-tinted lenses transmitted similar circadian-proficient light as red-tinted lenses but transmitted more non-circadian-proficient light, resulting in higher transmission specificity. Orange-tinted lenses had the highest transmission specificity while limiting biologically active light exposure in ordinary lighting conditions. Glasses incorporating these lenses currently have the greatest potential to support circadian sleep-wake rhythms. [ABSTRACT FROM AUTHOR]

Teenagers of today sleep less than previous generations. Technology is largely to blame for keeping people perpetually connected in the digital world which is in turn driven by changing social demands for immediacy as a form of intimacy. The consequences for teenagers are later bed times, reduced total sleep time and a degree of sleep catch up on weekends. This is termed chronic sleep deprivation or "social jetlag". The consequences of chronic sleep deprivation are underappreciated in the medical setting. They include altered mood, more somatic and psychological symptomatology, greater anxiety, more school absenteeism, reduced educational results and compromised vocational aspirations. Engagement with reluctant teenagers and their parents may be challenging and at times frustrating for all concerned. Much of the art of improving outcomes involves developing a rapport with the teenager, assisting them to gain insight into the problems associated with chronic sleep deficiency and fostering commitment from all family members to implement unpopular boundaries on the use of technology. [ABSTRACT FROM AUTHOR]

Narcolepsy type 1 (NT1) deeply impacts on quality of life, especially during adolescence, with NT1 children and adolescents that frequently report difficulties in integration with peers and decreased participation in after-school activities. Here we describe the case of NT1 teenager girl presenting with severe physical and social withdrawal, fulfilling the proposed diagnostic criteria for hikikomori, together with the classic NT1 symptoms. Social withdrawal is an overlooked phenomenon among NT1 children and adolescents that, if present, require a multidisciplinary approach and personalized interventions, but patients can benefit from NT1 pharmacological treatment.

Circadian rhythm disorders constitute a group of phenotypes that usually present as altered sleep-wake schedules. Until a human genetics approach was applied to investigate these traits, the genetic components regulating human circadian rhythm and sleep behaviors remained mysterious. Steady advances in the last decade have dramatically improved our understanding of the genes involved in circadian rhythmicity and sleep regulation. Finding these genes presents new opportunities to use a wide range of approaches, including in vitro molecular studies and in vivo animal modeling, to elevate our understanding of how sleep and circadian rhythms are regulated and maintained. Ultimately, this knowledge will reveal how circadian and sleep disruption contribute to various ailments and shed light on how best to maintain and recover good health.

Narcolepsy type 1 (NT1) deeply impacts on quality of life, especially during adolescence, with NT1 children and adolescents that frequently report difficulties in integration with peers and decreased participation in after-school activities. Here we describe the case of NT1 teenager girl presenting with severe physical and social withdrawal, fulfilling the proposed diagnostic criteria for hikikomori, together with the classic NT1 symptoms. Social withdrawal is an overlooked phenomenon among NT1 children and adolescents that, if present, require a multidisciplinary approach and personalized interventions, but patients can benefit from NT1 pharmacological treatment. [ABSTRACT FROM AUTHOR]

This protocol paper describes the development of an international collaboration to survey several thousand adults from different countries around the world about their sleep during the coronavirus disease 2019 (COVID‐19) pandemic. It is based on the development of a harmonised survey with 50 questions (106 different items) on sleep habits and sleep symptoms that permit comparability of information. The harmonised questionnaire may be used in anonymous cross‐sectional surveys, and the instruments within the questionnaire may also be used in prospective studies and clinical studies. The aim was to develop a questionnaire to sample a variety of sleep–wake disorders and other symptoms likely to be caused by prolonged social confinement or by having had COVID‐19. The questionnaire was designed to be: (a) simple and, (b) free to use, for research purposes, (c) multilingual, and (d) comprehensive. It can be completed in <30 min. By the end of June 2020, the survey questionnaire had been administered in Austria, Canada, China, Finland, France, Germany, Hong Kong, Italy, Japan, Norway, Poland, Sweden, UK and USA. Research questions to be addressed by the pooled data derived from the participating sites focus on describing the nature and rates of various sleep and circadian rhythms symptoms, as well as their psychological and medical correlates, that arise at various points during the COVID‐19 pandemic. [ABSTRACT FROM AUTHOR]

The present study proposes a classification model for the differential diagnosis of primary insomnia (PI) and delayed sleep phase disorder (DSPD), applying machine learning methods to circadian parameters obtained from ambulatory circadian monitoring (ACM). Nineteen healthy controls and 242 patients (PI = 184; DSPD = 58) were selected for a retrospective and non-interventional study from an anonymized Circadian Health Database (https://kronowizard.um.es/). ACM records wrist temperature (T), motor activity (A), body position (P), and environmental light exposure (L) rhythms during a whole week. Sleep was inferred from the integrated variable TAP (from temperature, activity, and position). Non-parametric analyses of TAP and estimated sleep yielded indexes of interdaily stability (IS), intradaily variability (IV), relative amplitude (RA), and a global circadian function index (CFI). Mid-sleep and mid-wake times were estimated from the central time of TAP-L5 (five consecutive hours of lowest values) and TAP-M10 (10 consecutive hours of maximum values), respectively. The most discriminative parameters, determined by ANOVA, Chi-squared, and information gain criteria analysis, were employed to build a decision tree, using machine learning. This model differentiated between healthy controls, DSPD and three insomnia subgroups (compatible with onset, maintenance and mild insomnia), with accuracy, sensitivity, and AUC >85%. In conclusion, circadian parameters can be reliably and objectively used to discriminate and characterize different sleep and circadian disorders, such as DSPD and OI, which are commonly confounded, and between different subtypes of PI. Our findings highlight the importance of considering circadian rhythm assessment in sleep medicine.

This article reviews the literature on mood disorders and sleep disorders among children and adolescents. Research suggests that sleep plays an important role in the development, progression, and maintenance of mood disorder symptoms among children and adolescents. Sleep problems as early as maternal perinatal insomnia may predict and predate depression among youth. Children and adolescents who develop comorbid mood disorders and sleep problems represent a particularly high-risk group with more severe mood episode symptoms, higher rates of self-harm and suicidality, and less responsivity to treatment. Treatment research supports the idea that sleep problems can be improved through behavioral interventions., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The present study proposes a classification model for the differential diagnosis of primary insomnia (PI) and delayed sleep phase disorder (DSPD), applying machine learning methods to circadian parameters obtained from ambulatory circadian monitoring (ACM). Nineteen healthy controls and 242 patients (PI = 184; DSPD = 58) were selected for a retrospective and non-interventional study from an anonymized Circadian Health Database (https://kronowizard.um.es/). ACM records wrist temperature (T), motor activity (A), body position (P), and environmental light exposure (L) rhythms during a whole week. Sleep was inferred from the integrated variable TAP (from temperature, activity, and position). Non-parametric analyses of TAP and estimated sleep yielded indexes of interdaily stability (IS), intradaily variability (IV), relative amplitude (RA), and a global circadian function index (CFI). Mid-sleep and mid-wake times were estimated from the central time of TAP-L5 (five consecutive hours of lowest values) and TAP-M10 (10 consecutive hours of maximum values), respectively. The most discriminative parameters, determined by ANOVA, Chi-squared, and information gain criteria analysis, were employed to build a decision tree, using machine learning. This model differentiated between healthy controls, DSPD and three insomnia subgroups (compatible with onset, maintenance and mild insomnia), with accuracy, sensitivity, and AUC >85%. In conclusion, circadian parameters can be reliably and objectively used to discriminate and characterize different sleep and circadian disorders, such as DSPD and OI, which are commonly confounded, and between different subtypes of PI. Our findings highlight the importance of considering circadian rhythm assessment in sleep medicine. [ABSTRACT FROM AUTHOR]

Highlights • Impulsive individuals show delayed sleep phase and abnormal circadian entrainment. • Impulsive individuals also show shortened sleep duration and poor sleep quality. • Impulsivity and ADHD traits are associated with sleep and circadian disturbance. • Sleep and circadian disturbance may be of transdiagnositc importance. Abstract We report the relationship between daily rest-activity patterns and trait impulsivity in healthy young adults. The Barratt Impulsiveness Scale was used to identify high and low impulsive individuals among a group of 51 volunteers. Participants’ sleep behaviour and circadian rhythm function was assessed using week-long actigraphy. High impulsive individuals displayed phase-delayed patterns of sleep, a decreased total sleep time and sleep efficiency, and disrupted circadian function. Such outcomes were also associated with greater self-reported attention deficit hyperactivity disorder symptoms. The results highlight that sleep and circadian rhythm disturbances may be associated with impulsive traits replicating relationships described in psychiatric illnesses in which impulsivity is a core feature. [ABSTRACT FROM AUTHOR]

Many individuals with obsessive compulsive disorder (OCD) report difficulty falling asleep until later than desired. This may reflect a misalignment between the sleep-wake cycle and the natural light dark cycle. Delayed bedtimes are related to disruptions in cognitive processes, increases in repetitive negative thinking, and OCD symptoms. Misalignment is more common in higher latitudes. AIMS: We hypothesized that the prevalence of OCD would be positively correlated with latitude. A systematic review of the literature identified peer-reviewed publications with estimates of OCD prevalence in the general population. Twenty-four estimates of the lifetime prevalence of OCD were identified and showed that the prevalence of OCD was significantly positively correlated with latitude. Other potential alternative individual, community and study specific factors were not significantly correlated with OCD prevalence. Finally, parallel analyses of a “psychiatric control” (panic disorder) failed to find a significant relationship between panic disorder and latitude. Findings from this study support a relation between latitude and OCD and suggest potential specificity of the relation to OCD vs factors related to mental health concerns broadly. These findings are consistent with recent results suggesting that the timing of sleep may be important in OCD. Future work in this area is warranted. [ABSTRACT FROM AUTHOR]

Eating disorders and school refusal behavior with delayed sleep phase are pathologies associated with very different or even inverse school problems. It is through these two prisms that we will develop the idea of school care, which is being set up in the innovative framework of the Mediterranean Area of the Adolescent, integrating a National Education Unit within the Child and Adolescent Psychiatry unit. This specific care seems to us interesting in the adolescent because it allows a work in «natural» environment of certain difficulties related to the different psychiatric disorders and seems to us as a help to the revival of the adolescent process. [ABSTRACT FROM AUTHOR]

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Circadian rhythm sleep disorders are alterations that are characterized by a shift in the sleep-wake cycle relative to day and night, such as the delayed sleep phase disorder (DSPD), which is a retard of at least 2 hours in the sleep start. Typically, the patient falls asleep after 2 a.m. and wakes up after 10 a.m. and with symptom of sleep onset insomnia. The prevalence of DSPD in young adults is 0.48%, increasing to 3.3% in adolescents. Interestingly, patients with COVID-19 infection report anxiety due to the intensive care unit lockdown and constant exposure to bright light. In addition, post-COVID patients have an increased risk of developing DSPD. For example, in adolescent post-COVID patients, the prevalence of DSPD increases to 63.3%. Patients with DSPD also have alterations in metabolic health, poor school performance, cognitive impairment, and a higher risk of developing other diseases. The objective of the present review is therefore to describe the characteristics of DSPD during the COVID-19 pandemic and to outline its possible implications for physical health (eg, metabolism) and mental health (eg, anxiety or depression).

Adolescent insomnia is a common condition that negatively impacts a developing young adult’s mental and physical health. While the treatment of adult insomnia has been standardized, the treatment of pediatric insomnia is very practitioner-dependent and few large-scale studies are available to determine a standard recommended practice. There is great hope that as the adolescent medicine and sleep medicine fields flourish, larger cohort analyses will be performed to determine the prevalence and precipitating factors of adolescent insomnia, allowing for standardized treatment recommendations and systematic efforts to make these recommendations available to all adolescents.

Circadian rhythms strongly influence when we are sleepy and when we are alert. If the timing of these rhythms is later than normal, it can contribute to sleep onset insomnia. If the timing is earlier than normal, it can lead to early morning awakening insomnia. Therefore, management of these types of insomnia need to include treatments, such as bright light and melatonin, that will re-time the circadian rhythms to be more in synchrony with the desired timing of sleep. Sleep onset insomnia would benefit from morning light therapy and early evening melatonin administration, while early morning awakening insomnia benefits from late evening bright light therapy and possibly early morning melatonin administration. Chronic insomnia from any original cause will most likely have a behavioral or learned component that should be addressed with cognitive/behavioral therapy. Thus, insomnia usually has multifactorial causes needing a multipronged therapeutic approach. [ABSTRACT FROM AUTHOR]

A delayed sleep–wake and circadian rhythm often occurs during puberty. While some individuals only develop a delayed sleep phase (DSP), others will fulfill the criteria for the diagnosis of delayed sleep phase disorder (DSPD). All previous studies have however not separated DSP from DSPD, and, as a result, the prevalence and associated factors are largely unknown for the two conditions individually. We estimated the prevalence of DSP and DSPD in a Swedish cohort of adolescents and young adults. We also investigated associated factors in the two conditions relative to each other and individuals with no DSP. A questionnaire regarding sleep patterns, demographics, substance use/abuse and symptoms of depression, anxiety, worry and rumination was sent to 1000 randomly selected participants (16–26 years of age) in Uppsala, Sweden (response rate = 68%). DSP was defined as a late sleep onset and a preferred late wake-up time. The DSPD diagnosis was further operationalized according to the Diagnostic and Statistical Manual of Mental Disorders, Edition 5 (DSM-5) criteria including insomnia or excessive sleepiness, distress or dysfunction caused by the DSP and that the sleep problem had been evident for 3 months. DSP occurred at a frequency of 4.6% and DSPD at a frequency of 4% in the investigated cohort. DSP was more common in males and was associated with not attending educational activity or work, having shift work, nicotine and alcohol use and less rumination. DSPD was equally common in males and females and was associated with not attending educational activity or work and with elevated levels of anxiety. Both DSP and DSPD appear to be common in adolescents and young adults in this Swedish cohort. No educational activity or work was associated with both DSP and DSPD. However, there were also apparent differences between the two groups in shift work, substance use and mental health, relative to persons with no DSP. Thus, it seems reasonable to assess DSP and DSPD as distinct entities in future studies. [ABSTRACT FROM AUTHOR]

Objective We evaluated whether the association between Adult Attention-Deficit/Hyperactivity Disorder (ADHD) and Seasonal Affective Disorder (SAD) was mediated by the circadian rhythm. Method Data of 2239 persons from the Netherlands Study of Depression and Anxiety (NESDA) were used. Two groups were compared: with clinically significant ADHD symptoms (N = 175) and with No ADHD symptoms (N = 2064). Sleep parameters were sleep-onset and offset times, mid sleep and sleep duration from the Munich Chronotype Questionnaire. We identified the prevalence of probable SAD and subsyndromal SAD using the Seasonal Pattern Assessment Questionnaire (SPAQ). Clinically significant ADHD symptoms were identified by using a T score>65 on the Conners Adult ADHD Rating Scale. Results The prevalence of probable SAD was estimated at 9.9% in the ADHD group (vs. 3.3% in the No ADHD group) and of probable s-SAD at 12.5% in the ADHD group (vs 4.6% in the No ADHD group). Regression analyses showed consistently significant associations between ADHD symptoms and probable SAD, even after adjustment for current depression and anxiety, age, sex, education, use of antidepressants and benzodiazepines (B = 1.81, p < 0.001). Late self-reported sleep onset was an important mediator in the significant relationship between ADHD symptoms and probable SAD, even after correction for confounders (total model effects: B = 0.14, p ≤ 0.001). Conclusion Both seasonal and circadian rhythm disturbances are significantly associated with ADHD symptoms. Delayed sleep onset time in ADHD may explain the increase in SAD symptoms. Treating patients with SAD for possible ADHD and delayed sleep onset time may reduce symptom severity in these complex patients. [ABSTRACT FROM AUTHOR]

Although individuals with delayed sleep wake phase disorder (DSWPD) and chronic insomnia disorder (CID) share many of the same phenomenological experiences, theories relating to the development and maintenance of these disorders are distinct in focus. Unlike CID, theory relating to DSWPD is primarily physiologically based and assumes almost no cognitive pathway. However, recent research findings suggest that individuals with DSWPD also display many of the sleep-disordered cognitive processes that were previously assumed to be unique to the insomnia experience. As such, this review aims to summarise current research findings to address the question "Could cognitive processes be involved in the development and maintenance of DSWPD?" In particular, the presence of cognitive and physiological pre-sleep arousal, sleep-related attentional bias, distorted perception of sleep and daytime functioning, dysfunctional beliefs and safety behaviours will be investigated. As this emerging area of research requires a stronger evidence base, we highlight suggestions for future investigation and provide preliminary practice points for clinicians assessing and treating "insomnia" in patients with DSWPD. [ABSTRACT FROM AUTHOR]

Background: Theoretical models of Bipolar Disorder (BD) highlight that sleep disturbances may be a marker of underlying circadian dysregulation. However, few studies of sleep in BD have reported on the most prevalent circadian sleep abnormality, namely Delayed Sleep Phase (DSP).Methods: A cross-sectional study of 404 adults with BD who met published clinical criteria for insomnia, hypersomnia or DSP, and who had previously participated in a study of sleep in BD using a comprehensive structured interview assessment.Results: About 10% of BD cases with a sleep problem met criteria for a DSP profile. The DSP group was younger and had a higher mean Body Mass Index (BMI) than the other groups. Also, DSP cases were significantly more likely to be prescribed mood stabilizers and antidepressant than insomnia cases. An exploratory analysis of selected symptom item ratings indicated that DSP was significantly more likely to be associated with impaired energy and activity levels.Limitations: The cross-sectional design precludes examination of longitudinal changes. DSP is identified by sleep profile, not by diagnostic criteria or objective sleep records such as actigraphy. The study uses data from a previous study to identify and examine the DSP group.Conclusions: The DSP group identified in this study can be differentiated from hypersomnia and insomnia groups on the basis of clinical and demographic features. The association of DSP with younger age, higher BMI and impaired energy and activity also suggest that this clinical profile may be a good proxy for underlying circadian dysregulation. [ABSTRACT FROM AUTHOR]