Sexual assault occurring when the victim is unable to consent or resist due to the use or administration of alcohol or drugs (i.e., incapacitated/drug-or-alcohol facilitated rape; IR/DAFR) is a particularly prevalent form of victimization experienced by college women. By definition, substance use precedes IR/DAFR; however, few studies have examined other potential risk factors for IR/DAFR that may be unique from those associated with forcible rape (FR; i.e., sexual assault occurring due to threats or physical restraint). The present investigation tested a model of risk for IR/DAFR and FR suggesting that child or adolescent sexual abuse (CASA) leads to posttraumatic stress disorder (PTSD) symptoms, which in turn increase the likelihood of IR/DAFR, but not FR. Results revealed full mediation for PTSD hyperarousal symptoms in the pathway between CASA and IR/DAFR, and partial mediation for hyperarousal symptoms in the pathway between CASA and FR. Theoretical and clinical implications are discussed.