Log-linear chi-square analyses were conducted to examine potential interactions between presence of pre-crime Axis I psychiatric diagnoses and differential levels of crime stress in association with posttraumatic stress disorder (PTSD) in a community sample of 295 female crime victims. High crime stress was defined as crime that included either perceived life threat, actual injury, or completed rape. Crime stress level was significantly associated with PTSD post-crime. Thirty-five percent of subjects with high crime stress exposure met criteria for PTSD, as opposed to 13% of those with low crime stress exposure. Pre-crime diagnosis was not associated with high crime stress exposure, indicating that this is not a vulnerability factor for exposure to crime characteristics associated with increased rates of PTSD. There were no significant independent associations between pre-crime Axis I diagnoses and PTSD post-crime. However, a significant interaction was observed between crime stress level, pre-crime depression, and PTSD, such that rate of PTSD was substantially higher in association with pre-crime depression, only in the high crime stress exposure group. Major findings are consistent with previous results implicating trauma exposure as the primary factor in development of PTSD. However, the results suggest that pre-crime depression may constitute a vulnerability factor for development of PTSD under conditions of high crime stress exposure. (Author)