The purpose of this research study is to determine the effectiveness of Atomoxetine, a medication approved for attention deficit hyperactivity disorder (ADHD), in improving quality of life as well as attention and mental skills such as memory, daily planning, and impulse control in Veterans with ADHD and post-traumatic stress disorder (PTSD). Reduced attention span, concentration difficulties, impaired inhibition and decision-making abilities, and memory problems are all symptoms of ADHD, and may be a factor in the current issue of PTSD treatment-resistance. Therefore, this study is aimed to examine the effect of atomoxetine on attention and executive function, which may lead to a significant improvement in overall ADHD and PTSD outcomes.