 This is a placebo-controlled clinical trial of prazosin vs. the SSRI paroxetine for combat trauma-related nightmares, sleep disturbance, and overall posttraumatic stress disorder PTSD clinical severity in OIFOEF returnees. Both neurobiologic considerations and our preliminary clinical treatment data provide support for the proposed trial. Preclinical and clinical studies suggest a role for increased central nervous system CNS adrenergic outflow andor responsiveness in PTSD pathophysiology. Possible mechanisms include alpha-1 adrenergic receptor-mediated effects on sleep physiology, corticotropin releasing hormone secretion, and disruption of cognitive processing. 