Combined Treatment of Prolonged Exposure and Pramipexole for Posttraumatic Stress Disorder and Depression

Approximately half of the individuals with posttraumatic stress disorder (PTSD) present with major depressive disorder (MDD). Compared to PTSD alone, patients with comorbid PTSD-MDD demonstrate greater distress and poorer treatment outcome. Functional magnetic resonance imaging (fMRI) show that relative to PTSD alone, PTSD-MDD is associated with decreased resting state functional connectivity (rs-FC) in both fear- and reward-processing circuits. In addition, our data suggest that Prolonged Exposure (PE), first-line PTSD treatment, may successfully target impairments in the fear circuits, but not in the reward circuits, which may explain the treatment-refractory quality of PTSD-MDD. The goal of this pilot study is to test the feasibility, safety and initial efficacy of an integrated therapeutic approach targeting both fear and reward impairments in PTSD-MDD patients. Specifically, the investigators will examine a combination treatment with PE, shown to effectively address fear circuitry deficits, and Pramipexole, a dopamine agonist, shown to increase reward circuit function and to have promise in treating depression but not previously studied in PTSD. The central hypothesis is that combined PE/Pramipexole will a) improve PTSD and depressive symptoms in PTSD-MDD patients, and b) increase functional connectivity of fear and reward pathways as measured by fMRI rs-FC. In this pilot study, 15 adults aged 18-60 years with PTSD-MDD will receive combined 10-week of PE and Pramipexole up to the maximum dose of 4mg a day. Clinical assessment will be conducted at baseline, week 5, post treatment and at 3-month follow up. Behaviorally assessments including the probabilistic reward task (PRT) and attention allocation tasks, and fMRI scans for resting state functional connectivity (rs-FC) will be conducted at baseline and end of treatment.