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Session Schedule

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0:00:00
Introduction

0:01:50
The pathophysiology of DSWPD and its subtyping
Sabra Abbott (United States)

0:18:05
The consensus on DLMO measurement, and its applications to a longitudinal cohort of adolescents
Shantha Rajaratnam (Australia)

0:32:10
Comprehensive features of circadian disorders and their relevance to psychiatric disorders
Nicholas Meyer (United Kingdom)

0:50:50
Possible internal desynchronization in DSWPD and N24SWD and its relevance to comorbidity and behavior
Tsuyoshi Kitajima (Japan)

1:06:00
Circadian measurements and interventions for CRSWDs with a focus on N24SWD and its comorbidity
Corrado Garbazza (Switzerland)

1:25:55
Question and answer

Summary

Circadian rhythm sleep-wake disorders (CRSWDs), especially delayed sleep-wake phase disorder (DSWPD) and non-24-hour sleep-wake rhythm disorder (N24SWD), are chronic conditions that impact the health and social functioning of many adolescents and young adults. The etiology of CRSWDs remains to be elucidated, and treatment options are limited. A key component of these disorders are psychiatric comorbidities, particularly mood and neurodevelopmental disorders. CRSWDs and comorbid disorders have clinically bidirectional relationships and have been suggested to share some pathophysiological basis.
Another important aspect of CRSWDs is their relevance to psychopathology and associated behaviors. On the one hand, behavior can alter the sleep-wake cycle and impact light exposure; on the other hand, the above-mentioned comorbidities and circadian preferences could also drive behavior. Strikingly, recent studies have revealed that more than 40% of patients with DSWPD do not exhibit a delayed endogenous melatonin rhythm, as previously believed, implying that the phase shift of the central circadian pacemaker is not the only explanation for this condition. Therefore, although it is widely assumed that patients with CRSWD are affected by an alteration of the endogenous circadian timing system or misalignment between the endogenous circadian rhythm and the individual sleep-wake schedule, there is an urgent need for a more comprehensive understanding of the pathophysiology of these disorders in order to guide personalized treatments.
This symposium will focus on the relationship between CRSWDs and associated behaviors and comorbidity, and the possibility that a dissociation between the sleep-wake cycle and the central circadian pacemaker may play an essential role. Appropriate circadian assessment of CRSWDs is therefore crucial, and should include technical tools to determine circadian phase and period, which should be widely available in clinical and research settings. As an example, N24SWD has a bidirectional relationship with DSWPD, and the longer circadian period in these patients provides further hints to its relationship with the central pacemaker and implication of comorbidity. Another essential aspect is the implication of the homeostatic process of sleep regulation, which interacts with the central pacemaker and is an important factor for CRSWDs’ comorbidity and behavior. These aspects are woven into the symposium discussion to uncover the multidimensional features of CRSWD pathophysiology.
The aim of this symposium is to enhance international cooperation in CRSWD research and clinical settings, deepen understanding of these challenging conditions, and share cutting-edge knowledge and insights into these conditions with global researchers and practitioners. This may lead to updated descriptions of these disorders and improved treatment strategies, contributing to the well-being of affected youth.

Learning Objectives:

Upon completion of this CME activity, participants will be able to:
• Recognize the proposed subtypes of DSWPD and their relevance to the circadian regulatory system
• Know the required standards for measuring melatonin rhythm at home and its implications
• Obtain a thorough understanding of the relationship between CRSWDs and psychiatric comorbidities, and the sleep-wake regulatory system
• Gain insight into the behavioral aspects of CRSWDs and their relevance to the pathophysiology
• Have advanced knowledge of circadian measurements and interventions related to CRSWDs and their comorbidities