According to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, posttraumatic stress disorder (PTSD) is characterized by three major symptom clusters following an event that elicited fear, helplessness, or horror. This review will examine each symptom cluster of PTSD separately, giving case study examples of patients who exhibit a preponderance of a given symptom domain. We use a translational approach in describing the underlying neurobiology that is relevant to particular symptoms and treatment options, thus showing how clinical practice can benefit from current research. By focusing on symptom clusters, we provide a more specific view of individual patient's clinical presentations, in order to better address treatment needs. Finally, the review will also address potential genetic approaches to treatment as another form of individualized treatment.