Controversies in the etiology-diagnosis of chronic insomnia: new insight from neurobiology findings

Insomnia is the most prevalent sleep disorder and is associated with significant morbidity and healthcare cost. It is frequently a result of mental and medical disorders, and is a risk factor for depression, hypertension, and other diseases. Thus, its proper diagnosis and treatment is of importance to medicine and psychiatry. In this presentation, we will address four longstanding central questions in the etiology-diagnosis of chronic insomnia. First, is chronic insomnia a disorder of sleep loss or a disorder of physiologic and emotional hyperarousal? Second, is there a physiological vulnerability in addition to the psychological one in developing chronic insomnia? Third, is the underlying pathophysiology of chronic insomnia associated with depression, similar or different than that of depression? Fourth, is polysomnography and, in general, objective measures of sleep, useful in the diagnosis of chronic insomnia? Our thesis on these four questions will be presented based on an integration of previously published clinical and epidemiologic research and new neurobiology findings from the Hershey group and others.