The primary purpose of this study is to test whether and how cognitive-behavioral therapy for insomnia (CBTi), a well-supported and highly effective insomnia treatment, may directly improve Posttraumatic Stress Disorder (PTSD) and Major Depressive Disorder (MDD) symptoms. The study is designed as a randomized controlled trial (RCT) to test the effect of CBTi on symptoms of PTSD and co-morbid depression prior to an evidence-based PTSD intervention and to assess the role of neurobiological processes and sleep architecture in mediating treatment outcomes.

Posttraumatic Stress Disorder (PTSD), which occurs in at least 15-20% of individuals exposed to a traumatic event, is a chronic condition associated with the development of a multitude of negative physical and mental health consequences and the co-occurrence of Major Depressive Disorder (MDD). Sleep disturbances, and especially nightmares and insomnia, are quite common in patients with PTSD, but the standard treatments for PTSD do not directly focus on sleep problems. Perhaps as a result, sleep disturbances are one of the most common residual symptoms following both PTSD treatments and depression treatments. Importantly, insomnia, depression and PTSD are each characterized by similar biological dysregulation, including alterations in important aspects of sleep (rapid eye movement sleep and slow wave sleep) as well as processes linked to health and disease (stress system responses and inflammatory processes).

Directly treating sleep in the context of PTSD and MDD is feasible and can lead to robust improvements in sleep, though whether improving sleep can enhance PTSD and MDD outcomes remains to be established. This study will enroll and randomize 150 participants with PTSD, MDD and insomnia. Following baseline assessments (T1) participants will be randomized to receive cognitive-behavioral therapy for insomnia(CBTi), a well-supported and highly effective insomnia treatment, or to a monitor only control condition. Following this first intervention period all participants will receive cognitive processing therapy, a trauma focused therapy with known effects on PTSD and depression. The study will test whether and how CBTi may(1) achieve improvements in PTSD and MDD symptom severity and (2) lead to enhanced response to subsequent treatment with cognitive processing therapy.

Intervening with CBTi prior to a PTSD-specific treatment and measuring biomarkers longitudinally, will allow for the testing of specific effects of sleep improvement on PTSD, depressive symptoms, objective aspects sleep and stress and inflammatory markers, thereby advancing basic understanding of biobehavioral mechanisms in PTSD and depression. Importantly, the proposed approach utilizes a treatment sequence that may appeal to trauma survivors with post-traumatic event symptoms who may be resistant to or unprepared to fully engage in standard PTSD treatments. Confirmation of the study hypotheses could support immediate translation of the findings to clinical practice.

Inclusion Criteria:

• must be English-speaking
• age 18-64 years old
• with exposure to trauma from interpersonal violence in the past year
• meet diagnostic criteria for full or subthreshold PTSD
• meet diagnostic criteria for MDD
• meet criteria for Insomnia Disorder

Exclusion Criteria:

• untreated sleep disorders other than insomnia or nightmares
• dementia or cognitive impairment
• history of schizophrenia or bipolar I disorder
• current suicidality
• health conditions with immunological components or taking immunosuppressive therapies
• active alcohol dependence
• medication use including antipsychotics, opiate analgesics, and sleep medications

To be determined.