AbstractAs many World War II and Korean Conflict veterans suffering from posttraumatic stress disorder (PTSD) grow older, increasing numbers will be diagnosed with dementia. We retrospectively analyzed patients with dementia, comparing the behavioral disturbances of those with PTSD to those without PTSD. We hypothesized that due to the additive effect of the neurobiological and behavioral changes associated with PTSD and dementia, the dementia with PTSD group would show more agitation and disinhibition than the dementia without PTSD group. Sixteen patients with diagnoses of dementia and PTSD were matched on age and Mini‐Mental States Examination (MMSE) scores to 16 patients with dementia without PTSD. Demographic characteristics, co‐morbid diagnoses, global Assessment of Functioning (GAF), Cohen‐Mansfield Agitation Inventory (CMAI), and paranoid items of Brief Psychiatric Rating Scale (BPRS) and Positive and Negative Syndrome Scale for Schizophrenia (PANSS) were assessed. The patients with diagnoses of dementia with PTSD did not differ significantly in their clinical presentation, hospital course, and condition at discharge from patients with dementia without PTSD. Chi‐square analysis showed that significantly more subjects in the PTSD group were prescribed anti‐depressants compared to the non‐PTSD group. Interestingly, within the PTSD group, the subgroup of patients who were former prisoners of war had a significantly higher mean score for paranoia and significantly less verbal agitation. This pilot study reveals that a diagnosis of PTSD alone is not sufficient to influence behavior in veterans with dementia; however, we also present provocative results that patients with more severe trauma (POW) do have changes in their behavior. Copyright © 2001 John Wiley & Sons, Ltd.