Sleep Disorders: Diagnosis and Therapeutics PDF

Preface

PHILOSOPHY

Sleep is a universal biological phenomenon and accounts for the way humans spend a third of their lives. Sleep disorders are increasingly recognized as significant public health challenges and are being included in research and policy agendas. These developments have been the result of, and have further stimulated, research efforts into the mechanisms and causes of sleep disturbances.

Sleep medicine is a relatively new specialty that, since its inception only two decades ago, has continued to make fundamental discoveries in many areas. Along with the increasing recognition of the contribution of sleep disturbances to overall health have been a number of advances in basic research. From discoveries in sleep pharmacology have come important insights into how drugs affect the basic mechanisms of both normal and disturbed sleep. These discoveries have represented some of the most important contributions to progress in the field. It was the interest of the editors in teaching and research that prompted them to engage in the collaborative effort that made Sleep Disorders: Diagnosis and Therapeutics a reality.

Throughout the evolution of this book and in selecting contributions for inclusion, the editors have sought to recognize the importance of pharmacology in the major areas of sleep medicine. Sections relating to systems, experimental, and clinical neuropharmacology and therapeutics are vital and dynamic areas within sleep medicine generally and it is thus reasonable to consider them essential components of sleep medicine curricula. Despite its overall relevance, the subject of pharmacotherapy for sleep disorders now encompasses such a broad range of topics that different sleep medicine training programs may wish to select certain areas for emphasis. The editors feel that the content of this volume is sufficiently comprehensive to allow this freedom of choice.

Many recent discoveries in both the laboratory and the clinical setting have increased rapidly our understanding of sleep medicine and neuropharmacology. These are being continually reported in the clinical neuroscience literature, as well as in publications dedicated to the topic of sleep and in other subspecialty journals. Sleep medicine is thus becoming increasingly interdisciplinary, while other areas of neuroscience and psychopharmacology are beginning to take an interest in the subject of sleep. A parallel development is that these fields are now reorganizing themselves at higher levels of complexity; consequently, it is becoming increasingly challenging for the sleep physiology researcher to assimilate, let alone master, the relevant findings in each of these fields.

To address this challenge, the editors of this book have assembled chapters that summarize and review some of the latest discoveries on basic and clinical sleep medicine, sleep physiology, and sleep pharmacology. To this end, a number of outstanding contributions have been sought from acknowledged experts in their respective fields. The goal of the book has therefore been to present the more recent developments in the fields of sleep and neuropsychopharmacology and to provide a context for considering them both in depth and from a multidisciplinary perspective.

We have kept the book up to date in terms of new concepts and applications and have tried to convey the excitement of the field. Thus, we have brought together the expertise of clinicians and basic researchers representing a range of interests in neuroscience, neuropharmacology, sleep physiology, and biological rhythms.

A CLOSER LOOK AT COVERAGE AND ORGANIZATION

Over the 40 years since the introduction of benzodiazepines (BZDs), the fields of pharmacology and the relatively new field of sleep medicine have evolved substantially. Traditionally, BZDs are known for their potential for abuse as well as for their association with withdrawal symptoms on discontinuation. These well-known characteristics of BZDs have made many physicians reluctant to prescribe centrally acting agents for sleep disorders and have thus led them to choose other non-pharmacological therapies. Currently, there are many drugs under development for the treatment of insomnia and other sleep disorders. It is the editors' hope that this book will assist the reader in keeping abreast of these new developments. It represents a comprehensive review, but is also thoroughly referenced for the reader who has specific questions or interests. The topics included here deal with the history of drug development, the advantages and disadvantages of particular drugs, and their mechanisms of action, including how they affect various neurotransmitter systems.

This book comprises 55 chapters, it considers sleep abnormalities in their many manifestations. Although this book is intended primarily for the clinician, its contents deal broadly with basic research in neuropharmacology and neuropsychology. It begins with a review of various practical matters such as sleep complaints and sleepiness. An extensive section deals with one of the most common groups of disorders seen at all levels of medical care: namely, the insomnias. Following this, the numerous approaches to the therapy of sleep disorders are overviewed and, further, how pharmacological agents may play a role in an effective therapy program.

The next section is devoted to a group of newer drugs that are the current treatments of choice in many countries – the so-called ‘z-drugs'. They are reviewed in detail, inasmuch as they are generally viewed as a distinct improvement on their predecessors, the benzodiazepines. The next section details the melatonin agonists, another group of agents that is of considerable current interest. Their actions on melatonin receptors are thought to target basic sleep regulatory mechanisms, but without most of the side effects of older medications.

Co-morbid conditions such as insomnia are a common complication of many disorders seen particularly in secondary care. Insomnia can be a problem in schizophrenia and epilepsy, and drugs used to treat these conditions often have major effects on sleep. Insomnia can also be a consequence of transient conditions such as jet lag. In this era of inexpensive flights over several time zones, jet lag symptoms are a nuisance to many people and very upsetting to some. Alcohol is a major factor in sleep impairment and, like many other active agents, can impair daytime performance in areas such as traffic safety. These and related topics are reviewed in this book.

The syndrome of restless legs, which can be both the result of and can cause sleep disruption, is the subject of the next two chapters. Narcolepsy is another condition that is much better understood with improved and more specific remedies being introduced: it is reviewed in three chapters. Finally, sleep and dreaming are discussed.

A number of important appendices have been added. These include The Subjective Measurement of Excessive Daytime Sleepiness, The Multiple Sleep Latency Test and Maintenance of Wakefulness Test: Use and Procedures, The OSLER test, The Pittsburgh Sleep Quality Index (PSQI), Pittsburgh Insomnia Rating Scale (PIRS), The Athens Insomnia Scale (AIS), The Leeds Sleep Evaluation Scale (LSEQ) for psychopharmacological research, Sleep Hygiene Practice Scale Cyclic Alternating Pattern (CAP), and the body mass index (BMI) chart.

Our choice of subjects was heavily influenced by the suggestions and recommendations of some of the world's leading experts who have contributed detailed reviews in their areas of expertise, backed up by extensive bibliographies. Of necessity, compromises have been made in terms of depth, breadth of coverage, and reasonable size. Inevitably there is some overlap of subject matter, but additionally some omissions did occur despite the fact that the editors sought contributions from leading experts in each field. It is our intention to address these needs in future editions of this book. The authors that were approached are busy people, and we express our wholehearted gratitude to them for their contributions. We trust that being a member of such a distinguished group of authors is the true academic reward.

The reader may feel confident that the information presented is based on the most recent sleep pharmacology literature. Furthermore, the importance of this information to medicine and therapeutics is stressed. Some of the information presented concerning older sedative hypnotics will be familiar to informed readers and will demonstrate to them how their previously acquired knowledge can be applied to the therapeutic options for the treatment of sleep disorders. Information about specific drugs may also be recapitulated throughout this volume by multiple authors. This redundancy may confer added value, inasmuch as the reader may benefit from more than one perspective on a phenomenon or collection of research findings.

This book is intended for sleep physicians, psychiatrists, psychologists, basic sleep researchers, and generalists alike. It can be useful for graduate students of biomedical and sleep medicine subspecialties. It will be of interest to other readers who want to get an overall grasp of sleep pharmacology and therapeutics and to those physicians who evaluate and treat sleep disorders. In addition, it will be useful to pharmacologists, pharmacists, medical students and clinicians of various disciplines who seek an overall grasp of the clinical pharmacology of sleep.

Our goal has been to provide a concise yet comprehensive review of the expanding and increasingly multidisciplinary area of sleep medicine. We hope that readers will find that this effort represents a thoughtful balance of basic experimental and clinical viewpoints and, furthermore, will serve as a foundation for understanding and ultimately treating sleep disorders. We hope that such selection of chapters and appendices will make the material more accessible and more attractive to the readers.

Today, physicians and sleep specialists have an impressive array of powerful and elegant tools for obtaining qualitative and quantitative information about the sleep disorders. The effectiveness of treatment requires an appreciation of such tools and techniques and how they can be used to treat sleep disorders. It is our belief that the choice and efficient use of modern tools and techniques requires an understanding of the fundamental principles upon which they are based.

In summary, this book surveys the roles of various pharmacological agents in sleep pathology. Because this book is primarily written for clinicians and medical students, it highlights the clinical features of the various sleep disorders and therapeutic options and some are considered in depth.

It is our hope that this book will, in a modest fashion, enable interested scientific and medical persons to approach sleep disorders with a better understanding of their scope and pathogenesis and of the science and practice of the sleep medicine. We also hope that this book contributes to the education of individuals wanting to learn more about the pharmacotherapy of sleep disorders and, perhaps, generate new ideas and renewed interest that will provide a better understanding of the cause of sleep disorders, leading to improvements in the care of patients who suffer from them.

Inasmuch as we envisage continuing updates and new editions of this book, readers are encouraged to contact us with feedback on its contents, with particular regard to omissions and inaccuracies, and any thoughts or suggestion for revisions. Such feedback is essential to the continued development of the book.