This systematic review analyzed data from studies examining memory and cognitive function in subjects with posttraumatic stress disorder (PTSD), compared with subjects exposed to trauma (but without PTSD). Based on analysis of 21 articles published in English from 1968 to 2009, the conclusion is that individuals with PTSD, particularly veterans, show signs of cognitive impairment when tested with neuropsychological instruments, more so than individuals exposed to trauma who do not have PTSD.