Inconsistency in reporting potentially traumatic events

Research on post-traumatic stress disorder (PTSD) relies mainly on self-reports of exposure to trauma and its consequences. To analyse the consistency of the reporting of potentially traumatic events (PTEs) over time. A community-based cohort, representative of the canton of Zurich, Switzerland, was interviewed at the ages of 34-35 years (in 1993) and 40-41 years (in 1999). A semi-structured diagnostic interview, including a section on PTSD, was administered. Of the 342 participants who attended both interviews, 169 reported some PTE (1993, n=110; 1999, n=120). In 1999, 56 participants (33.1%) reported for the first time PTEs that actually occurred before 1993, but which had not been reported in the 1993 interview. In total, 68 participants (40.2%) who had reported a PTE in 1993 did not report it in 1999. The overall frequency of inconsistent reporting was 63.9%. The high level of inconsistency in the reporting of PTEs has implications for therapy as well as for research.