Purpose: Mild traumatic brain injury (TBI) is extremely common among OEF/OIF (Operation Enduring Freedom/Operation Iraqi Freedom) era Veterans. Mild TBI is frequently accompanied by post-traumatic stress disorder (PTSD) and depression symptoms, co-occurring disorders that contribute to increased disability and decreased quality of life. Neuroactive steroids (NS) represent promising pharmacological candidates for intervention for these diverse symptom domains, since a number of these molecules demonstrate pronounced neuroprotective and neurotrophic properties. The NS pregnenolone (PREG) is a logical therapeutic option, since it enhances learning and memory and also increases myelination in rodent models. Further, decreases in PREG have been associated with depressive symptoms, and PREG is also metabolized to allopregnanolone (ALLO), an anxiolytic downstream NS that is decreased in PTSD. ALLO also enhances neurogenesis in rodents. The investigators thus propose an RCT in OEF/OIF era Veterans with mild TBI.~Methodology: The design of this study will be randomized, placebo-controlled, double-blind. Trial duration will be 10 weeks, consisting of a 2-week placebo lead-in period for all subjects, followed by 8 weeks of treatment with either pregnenolone or placebo. The primary cognitive outcome measure will be executive functioning (as assessed by the Tower of London test), and the primary behavioral outcome measure will be PTSD Cluster D symptoms (as assessed by the Clinician-Administered PTSD Scale, CAPS). The investigators will also determine if PREG administration in OEF/OIF Veterans with mild TBI increases downstream ALLO and/or other GABAergic NS levels, and the investigators will identify the specific metabolism profile of PREG following eight weeks of treatment with this neurosteroid. A subset of patients will also receive pre/post neuroimaging (functional magnetic resonance imaging [fMRI], diffusion tensor imaging [DTI], and quantitative susceptibility mapping/susceptibility tensor imaging [QSM/STI]).~Anticipated Findings: The investigators hypothesize that treatment with PREG in OEF/OIF era Veterans with mild TBI will significantly improve executive functioning compared to the placebo condition. The investigators also predict that treatment with PREG will decrease Cluster D PTSD symptoms compared to treatment with placebo.
Purpose: Mild traumatic brain injury (TBI) is extremely common among Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) era Veterans. Mild TBI is frequently accompanied by post-traumatic stress disorder (PTSD) and depression symptoms, co-occurring disorders that contribute to increased disability and decreased quality of life. Neuroactive steroids (NS) represent promising pharmacological candidates for intervention for these diverse symptom domains, since a number of these molecules demonstrate pronounced neuroprotective and neurotrophic properties. The NS pregnenolone (PREG) is a logical therapeutic option, since it enhances learning and memory and also increases myelination in rodent models. Further, decreases in PREG have been associated with depressive symptoms, and PREG is also metabolized to allopregnanolone (ALLO), an anxiolytic downstream NS that is decreased in PTSD. ALLO also enhances neurogenesis in rodents. The investigators thus propose an randomized controlled trial (RCT) in OEF/OIF era Veterans with mild TBI.~Methodology: The design of this study will be randomized, placebo-controlled, double-blind. Trial duration will be 10 weeks, consisting of a 2-week placebo lead-in period for all subjects, followed by 8 weeks of treatment with either pregnenolone or placebo. The primary cognitive outcome measure will be executive functioning (as assessed by the Tower of London test), and the primary behavioral outcome measure will be PTSD Cluster D symptoms (as assessed by the Clinician-Administered PTSD Scale, CAPS). The investigators will also determine if PREG administration in OEF/OIF Veterans with mild TBI increases downstream ALLO and/or other GABAergic NS levels, and the investigators will identify the specific metabolism profile of PREG following eight weeks of treatment with this neurosteroid.~Anticipated Findings: The investigators hypothesize that treatment with PREG in OEF/OIF era Veterans with mild TBI will significantly improve executive functioning compared to the placebo condition. The investigators also predict that treatment with PREG will decrease Cluster D PTSD symptoms compared to treatment with placebo.