Evaluating the Reliability of Expert Evidence in Compensation Procedures: Are Diagnosticians Influenced by the Narrative Fallacy when Assessing the Psychological Injuries of Trauma Victims?

The current study investigated whether mental health practitioners are influenced by the narrative fallacy when assessing the psychological injuries of trauma victims. The narrative fallacy is associated with our tendency to establish logical links between different facts. In psychodiagnostic assessments, this tendency may result in overdiagnosis of mental disorders when psychological symptoms can be attributed to a traumatic event. Consequently, legal decision makers may be at risk of awarding compensation for psychological injuries which are not severe enough to justify financial reimbursement. To explore this topic, we asked Dutch mental health practitioners whether they would assign a diagnosis of mental disorder to fictitious symptoms of psychological injury. Each participant was presented with two vignettes. The first vignette described symptoms in terms of a generalized anxiety disorder; the second in terms of a major depressive episode. The vignettes varied in the cause (trauma versus cause not specified) and severity (near threshold of DSM diagnosis versus below threshold of DSM diagnosis) of the symptoms. Results indicated that participants more often assigned a diagnosis of mental disorder if the psychological symptoms had been caused by a traumatic event than if that had not been the case. Further analysis of the data suggested that this difference was due to the high numbers of assigned diagnoses of posttraumatic stress and acute stress disorder in the trauma conditions. It was speculated that participants filled in missing information to justify the assignment of such diagnoses, for example by imagining symptoms of intrusion and avoidance.