The purpose of this study is to obtain data investigating the safety and efficacy of eszopiclone for the treatment of post-traumatic stress disorder (PTSD)-related sleep disturbance and the impact of improved sleep with eszopiclone treatment on neuroendocrine correlates of PTSD. The investigators hypothesize that eszopiclone will be significantly more effective than placebo and well tolerated for PTSD-related sleep disturbance, improvement in sleep will be associated with improvement in overall PTSD symptoms, and patients with PTSD-related sleep disturbances will have abnormal levels of stress hormones.

Post-traumatic stress disorder (PTSD) is characterized by three symptom groupings: re-experiencing symptoms including flashbacks, nightmares, and intrusive memories; physiological hyperarousal; and avoidance symptoms. Of the three major categories of symptoms in PTSD listed by the Diagnostic and Statistical Manual of Mental Disorders, sleep-related problems are listed in two of them: difficulty falling asleep is considered an aspect of hyperarousal symptoms, and nightmares are a type of re-experiencing symptom. Both are found commonly in PTSD. Little is known about the relationship of neuroendocrine dysregulation in PTSD and sleep disturbance. It is possible that successful treatment of sleep disturbance in PTSD may alter an abnormal stress hormone pattern. The novel cyclopyrrolone hypnotic eszopiclone thus presents an intriguing opportunity to examine the treatment of sleep disturbances and nightmares in PTSD. This study will determine the safety, efficacy and impact on neuroendocrine parameters of eszopiclone compared to placebo for sleep disturbance and overall PTSD symptoms in individuals with PTSD and reported sleep disturbance.

Inclusion Criteria:

• Male or female outpatients 18-64 years of age with a primary diagnosis of PTSD as defined by DSM-IV criteria with associated sleep disturbance

Exclusion Criteria:

• Pregnant women, lactating women, and women of childbearing potential who are not using medically accepted forms of contraception.
• Concurrent use of other psychotropic medications, other than antidepressants at stable dose for at least 4 weeks prior to randomization
• Serious medical illness or instability
• Seizure disorders with the exception of a history of febrile seizures if they occurred during childhood
• Concurrent psychotherapy initiated within one month of randomization or ongoing psychotherapy of any duration directed specifically toward treatment of PTSD and/or sleep disturbance
• Diagnosis of schizophrenia, mental retardation, OCD, organic medical disorders or bipolar disorder, eating disorders in the past 6 months, alcohol or substance abuse in the past 3 months, or dependence within the past 6 months.
• Patients with significant suicidal ideation or who have enacted suicidal behaviors within 6 months prior to intake

Baseline data are unavailable for the 3 participants that did not complete the study, and therefore, the baseline data will only reflect the information of the 24 completed participants, instead of the 27 that began baseline.