The purpose of this study is to compare the effectiveness of two talk therapies for OEF/OIF Veterans at the Michael J. Crescenz and the West Haven VA Medical Centers. Participants will randomly receive one of two individual treatments intended to improve the sleep disturbance and nightmares of returning Veterans.

This is a dismantling study with the objective of determining whether imagery rehearsal is essential to the efficacy of imagery rehearsal + CBT-I for improving the sleep and nightmare disturbance in Veterans with PTSD and recurrent nightmares.

Inclusion Criteria:

• Currently enrolled in treatment in the Michael J. Crescenz VA Medical Center or VA Connecticut Healthcare System Mental Health Clinic
• Meets DSM-IV-R criteria for current PTSD (within the past month)
• Repetitive, military-related nightmares (at least 1 every 2 weeks, for at least 6 months)
• A global sleep disturbance, as indicated by a score of five or greater on the Pittsburgh Sleep Quality Index
• Ability to read and speak English
• A concurrent anxiety disorder or depressive disorder diagnosis will be allowed
• Dementia related to head injury and amnestic disorder related to head injury will be allowed

Exclusion Criteria:

• Current substance dependence
• Bipolar disorder
• Delirium
• Dementia that is not related to head injury
• Amnestic disorder that is not related to head injury
• Schizophrenia and other psychotic disorders
• Severe traumatic brain injury, as indicated by self-report (loss of consciousness or alteration of mental status greater than 24 hours, or peri-traumatic memory loss, or any posttraumatic amnesia greater than 7 days)
• The presence of diagnosed sleep disorders other than insomnia: narcolepsy, circadian rhythm sleep disorders, and periodic limb movement disorder. Participants in treatment for sleep apnea, or who have not benefited from or declined available treatment may be included.