PTSD that suggest that recall bias can lead to an overestimation of a dose–responsive relationship between exposure and outcome (Dohrenwend 2006). Current mood affects memory retrieval and both depressed and PTSD patients have impaired retrieval in terms of memory (Harvey and Bryant 2002). A study of motor vehicle accident victims who provided symptoms one month after the incident and were asked to recall those symptoms two years later found that the severity of the stress and injury and the trajectory of recovery can lead to over reporting or under-reporting of symptoms (Harvey and Bryant 2000). While the majority correctly recalled most of the symptom clusters, persons with few symptoms two years later tended to omit symptoms that they had reported in the acute phase of the disease, and persons with high levels of symptoms at the two year interview were more likely to recall the presence of acute symptoms that they had not reported in the initial assessment.
