Imaging causes and consequences of insomnia and sleep complaints

Introduction The contents of the present volume, on Neuroimaging of Sleep and Sleep Disorders, leave no doubt on the relevance of a good night’s sleep to support optimal brain function. For about one out of ten people, a good night’s sleep is not easily accomplished. They complain of a prolonged latency to fall asleep, problems in maintaining sleep, early morning awakening, or non-restorative sleep. They moreover report significant daytime cognitive, emotional, social, or professional impairments as a consequence of their troubled sleep. If this situation occurs at least three times a week and for at least three months, they are likely to have the diagnosis of insomnia. In most sufferers, insomnia is a chronic condition. Half of the people experiencing insomnia today will still suffer from it next year. Insomnia can occur in isolation, but is also a very common comorbidity with other disorders. With a prevalence of 6-11% in the general population, insomnia is the most frequent complaint in general practice, psychological practice, and the sleep clinic alike. Insomnia is an all but trivial complaint, and its impact on society cannot be overemphasized; not only with respect to the number of people suffering, but also with respect to its consequences. While its prevalence increases up to ~40% with aging, it is becoming evident that insomnia significantly increases the risk of developing the most common mental and physical health problems of our aging society, including depression, cardiovascular disease, obesity, and the metabolic syndrome (reviewed in [1, 2]).