Abstract
Disturbances of the sleep-wake pattern constitute one of the major complaints of patients with a wide range of psychiatric conditions, including major depression disorder, anxiety disorders, bipolar disorders, schizophrenia, borderline personality disorder, eating disorders, and alcohol abuse. Recent advances have cast light on the mecanisms underlying modifications in sleep in psychiatric disorders, offering new approaches in management and opening new avenues of research. Isnomnia and psychiatric disorders, especially depression, are intimately linked. Insomnia, defined as a difficulty in initiating and/or in maintaining sleep leading to daytime repercussions, is not simply a symptom of depression but an independent diagnostic entity, and is known to be an independent risk factor for both depression itself and the development of a new depression episode or relapse. To date, the psychological and neurobiological mechanisms underlying the relationships between insomnia and affective disorders are not yet fully understood. The review by Chiara Baglioni et al. examines the latest findings from several fields of research, with particular attention to alterations of the arousal system leading to hyperarousal and to the possible biological mechanisms involved in the link between sleep alteration, insomnia, regulation of emotion, and mood symptoms. Links between depression sleep and circadian rhythms have long been suspected due to the existence of seasonal depression, where the onset of low mood correlates with a reduction in day length. Seasonal affective disorder (SA) is primarily a circadian rhythm disorder. Alfred Lewy discusses the theory of misalignement between the circadian rhythm of melatonin secretion and the midpoint of the sleep bout, and emphasise the importance or careful timing of treatment administration (bright light or melatonin). Timing of treatment administration requiring detailed information on patients’ phase state and the role of new accessible tools such as dim light melatonine onset are evaluated as are different treatment modalities. The importance of biological rhythms in SA disorder has led to an interest in the role of circadian rhythms in the development of depression. The successes of chronobiotic treatments for SA disorder have led to the trialling of psychological and pharmacological treatments targeting circadian rhythms in unipolar major depression (MDD). The review by Sarah Hartley et al. focuses on the research linking circadian rhythms and depression, and on the evidence for effectiveness of chronobiotic treatments such as high intensity light, melatonin or melatonin agonist or behavioural therapy in MDD. The evidence base for novel antidepressants combining 5HT2c antagonist and melatonin agonist action in acute treatment of unipolar MDD and in relapse prevention is reviewed as is their use in clinical management of MDD. Managing bipolar disorder is a challenge for psychiatrists and it has been long known that sleep disorders are a sign of relapse. Carole Boudebesse et al. examine the evidence that sleep and circadian rhythms are disturbed in bipolar patients during both mood episodes and periods of remission. Therapeutic applications of chronobiology in bipolar disorder, such as specific psychosocial interventions, light therapy and physical exercise are described. Finally, psychiatrists are faced with frequent reports of sleep disorders in adults and children with attentiondeficit/ hyperactivity disorder (ADHD) and, conversely, sleep specialists report certain symptoms of ADHD (attention deficits, fidgeting) in patients suffering from primary sleep disorders. Are ADHD symptoms secondary to sleep fragmentation due to sleep disorders such as sleep disordered breathing and periodic legs movements, and treatable with treatment of these specific disorders? Could some ADHD subjects share a common deficit in the sleep/wake regulation systems resulting in sleep fragmentation? The pathophysiological relationship between sleep disorders and ADHD is complex and probably multidirectional. The hot topic from the team of Astrid Claret et al. reviews the latest research and aims to help clinicians in developing a framework for understanding and treating patients suffering from ADHD and sleep disorders.
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