Due to sustained military conflicts in Afghanistan and Iraq over the past decade, there are an increasing number of U.S. military personnel and Veterans returning home with posttraumatic stress disorder (PTSD) and comorbid alcohol use disorders (AUD) and substance use disorders (SUD). If left untreated, Veterans with co-occurring PTSD and substance use disorders are at increased risk for developing other mental health problems (e.g., depression, anxiety), suicidal ideation and attempts, physical health problems, reduced resiliency and military readiness, employment problems, violence, and family/relationship impairment. While mental health services are in place for U.S. service members, substantial gaps in the treatment of co-occurring PTSD and SUD exist and there is little scientific evidence available to guide the provision of care. As part of the Consortium to Alleviate PTSD (CAP), the proposed study directly addresses this critical knowledge gap by testing the efficacy of doxazosin, a long-acting and selective alpha-1 adrenergic antagonist, as compared to placebo in reducing PTSD and AUD/SUD severity among U.S. military personnel. The medication to be investigated (doxazosin) represents a novel treatment approach for PTSD and AUD/SUD. While prazosin, also an alpha-1 adrenergic antagonist, has been shown to improve sleep and nightmares in military personnel with PTSD and may help reduce substance use severity, it has a short half-life of 2-3 hours and requires multiple doses each day, which is a significant limitation. In several pilot studies, doxazosin has shown promise in significantly reducing symptoms of PTSD and AUD/SUD and, in contrast to prazosin, it requires once per day dosing which confers a significant advantage in terms of translating positive findings into routine clinical practice. In this Stage II study, the investigators will (1) employ a two-arm randomized, double-blind, between-groups experimental design that will consist of 12 weeks of treatment with doxazosin or placebo medication; (2) use standardized, repeated dependent measures to rigorously assess PTSD symptomatology and AUD/SUD severity; (3) measure impairment in associated mental and behavioral health problems (e.g., depression, anxiety, sleep, risky behaviors, family/social functioning); and (4) use functional magnetic resonance imaging (fMRI) to investigate the underlying pathophysiology of comorbid PTSD/AUD and identify prognostic indicators of treatment outcome. To achieve these aims, the investigators have assembled a multidisciplinary team of investigators with nationally-recognized expertise in combat-related PTSD, substance use disorders and neuroimaging who have successfully collaborated in the past and are uniquely qualified to implement this type of investigation. The investigators represent a collaboration of faculty at the Ralph H. Johnson Veterans Affairs (VA) Medical Center and the Medical University of South Carolina (MUSC) in Charleston, SC.
The proposed study will examine the efficacy of doxazosin in the treatment of PTSD and alcohol use disorder or substance use disorders.