Sleep Loss and Mechanisms of Impaired Glucose Metabolism

The purpose of this study is to test the effects of sleep and eszopiclone, a drug that helps people sleep, on how the body processes glucose (sugar). Eszopiclone is approved by the U.S. Food and Drug Administration (FDA) for sale for the treatment of insomnia. It is marketed in the United States as LUNESTA.

Main Hypothesis: Primary insomnia is associated with impairments of glucose metabolism that can be reversed by two months of eszopiclone for the primary insomnia

Insomnia is the most common sleep disorder, affecting nearly one-third of all adults in any given year, and chronically affecting 10-15% of the adult population. Reduced sleep time, independent of insomnia, has been associated with a variety of deleterious long term effects, including an increased risk of incident myocardial infarction and symptomatic diabetes. Chronic partial sleep loss or insomnia may impair glucose metabolism in the short term and are associated with the development of diabetes in the long term. Although the extent of sleep loss is more acute in the laboratory-based 'sleep debt' studies of healthy volunteers, chronic primary insomnia patients exhibit 'hyperarousal' (hypercortisolemia in the afternoon and evening, accelerated metabolism) similar to that seen with acute sleep deprivation. In addition, degradations of sleep quantity and quality in primary insomnia have been attributed to cognitive and somatic hyperarousal in the sleep setting. study examines and quantifies in adult men and women the link between primary insomnia and impaired glucose tolerance. This study examines the extent which adequate treatment of primary insomnia reverses impairments of glucose metabolism. If abnormalities of glucose metabolism are reversible, this study will demonstrate the importance of treatment of chronic primary insomnia.

Eligibility Criteria:
Inclusion Criteria:

* Age 25-55
* Complaint of insomnia of at least 6 months duration
* DSM-IV diagnosis of Primary Insomnia
* Sleep diary: mean Total Sleep Time \< 6 hours and a mean total wake time (sleep latency + wake after sleep onset) of greater than 60 minutes (in previous 14 days as recorded on sleep diary)
* A willingness to comply with study procedures
* If of child-bearing potential, using a medically-accepted method of birth control, including abstinence, barrier method with spermicide, steroidal contraceptive (oral, transdermal, implanted, and injected) in conjunction with a barrier method, and intrauterine device \[IUD\])

Exclusion Criteria:

* Current diagnosis of DSM-IV Axis I disorder other than Primary Insomnia
* Regular treatment (more than 1 time/week) with CNS active medication within 1 month of fist inpatient visit
* Treatment with medications that interfere with glucose metabolism including anti-diabetic medications or steroidal contraceptives
* Uncontrolled medical illness that would interfere with participation in the study
* Body Mass Index \>32 or \<19.8
* Current symptoms or diagnosis of any moderate to severe sleep disorder other than insomnia
* No menopausal or peri-menopausal symptoms that disrupt sleep
* Pregnant, lactating or planning to become pregnant
* Consumption of \> 2 caffeinated beverages per day (including coffee, tea and/or other caffeine-containing beverages or food) during 3 weeks prior to the start of the study