Intrusions and flashbacks are core features of posttraumatic stress disorder (PTSD). The frequency of these symptoms is usually assessed through retrospective questionnaires, which may be subject to recall bias of unknown magnitude. Electronic diaries that enable real-time assessment have been used to address recall biases in several psychiatric disorders. However, to our knowledge, this is the first study to apply this method to assess intrusions and flashbacks in PTSD related to childhood sexual abuse (CSA). Female patients with PTSD related to CSA (n = 28) were provided with electronic diaries for repeated real-time assessment of intrusions and flashbacks over the period of 1 week. At the end of this period, they were asked to retrospectively report how many such symptoms they recalled having experienced over the past week. The total number of symptoms reported in the electronic diaries (74.5 ± 62.0 intrusions and 24.4 ± 36.0 flashbacks for the week) was substantially higher than those reported in previous studies. Furthermore, electronic diaries revealed the occurrence of about 50% more intrusions and flashbacks than did the retrospective assessment (74.5 vs. 49.5 for intrusions, and 24.4 vs. 13.4 for flashbacks). Such high frequencies are not captured with existing assessment instruments and suggest a possible ceiling effect. Future research needs to clarify whether these high numbers are specific to highly symptomatic PTSD patients or might generalize to other populations of PTSD patients. (c) 2013 APA, all rights reserved.