Treatment of Comorbid Sleep Disorders and Post Traumatic Stress Disorder (PTSD)

Inclusion Criteria: * Aged 18-50. * Chronic Insomnia, as defined by the Diagnostic and Statistical Manual-fifth edition (DSM-5) (American Psychiatric Association, 2013) assessed with Structured Clinical Interview for DSM-5 Sleep Disorders (SCISD). * Chronic Nightmare Disorder, as defined by DSM-5, assessed with the SCISD. * PTSD, as defined by DSM-5, assessed by Clinician-Administered Posttraumatic Stress Scale-5 (CAPS-5). * Active duty military and recently discharged Veterans at Fort Hood eligible for treatment at Carl R. Darnall Army Medical Center (CRDAMC). * History of having deployed in support of combat operations following 9/11, assessed by self-report. * Stable on psychotropic and/or hypnotic medications and/or interventions for sleep (e.g., Continuous Positive Air Pressure for sleep apnea) administered by other providers for at least one month assessed by self-report and review of medical record. * Willing to refrain from new behavioral health or medication treatment for issues pertaining to sleep, PTSD, or nightmares during participation in the study. * Indication that the individual plans to be in the area for the 5 months following the first assessment. Exclusion Criteria: * Individuals who have been re-deployed from a theater of operation less than 3 months. * Current suicide or homicide risk meriting crisis intervention as assessed by the Patient Health Questionnaire (PHQ-9), The Depressive Symptom Index - Suicidality Subscale (DSI-SS), or the Self-Injurious Thoughts and Behaviors Interview (SITBI). * Inability to speak and read English. * Moderate to severe brain damage, assessed by the inability to comprehend the baseline questionnaires. * Pregnancy, assessed by self-report and review of medical record, because sleep disturbances due to pregnancy may be the result of different mechanisms and the proposed instruments and treatments have not been validated in this population. * Current circadian rhythm, environmental, sleep deprivation, or hypersomnia sleep disorder, assessed by self-report because CBTin has not been validated in these populations. * Other untreated sleep disorders to include individuals with clinically significant obstructive sleep apnea (Respiratory Disturbance Index \>5/hr), periodic limb movement disorder (PLMD; \>15/hr with arousals), nocturnal seizures, or a parasomnia (e.g., sleepwalking, confusional arousals, nocturnal eating and drinking syndrome), based on criteria from the International Classification of Sleep Disorders-third edition (American Academy of Sleep Medicine, 2013). Individuals meeting criteria for one of the above sleep disorders will be seen for clinical care at the CRDAMC Sleep Center. Once the aforementioned sleep disorder is stably treated, individuals meeting the study criteria for insomnia, nightmares, and PTSD can be reassessed for participation in this study. * Sleep efficiency \>85%, as assessed by the sleep diary. * Serious mental health diagnosis (e.g., bipolar disorder or psychosis) assessed with review of baseline questionnaires, review of medical record, and/or Mini International Neuropsychiatric Interview (MINI 7.0 Mania module). * Currently engaged in evidence-based psychotherapy for PTSD (i.e., Prolonged Exposure Therapy or Cognitive Processing Therapy) or Insomnia or nightmares (i.e., Cognitive Behavioral Therapy) by self-report and review of medical record.