Interviewer Effects on Epidemiologic Diagnoses of Posttraumatic Stress Disorder

• Published in: American journal of epidemiology Vol. 144; no. 6; pp. 589 - 597
• Main Authors: Grayson, D. A., O'Toole, B. I., Marshall, R. P., Schureck, R. J., Dobson, M., Ffrench, M., Pulvertaft, B., Meldrum, L.
• Format: Journal Article
• Language: English
• Published: Cary, NC Oxford University Press 15.09.1996
• Subjects: Adult and adolescent clinical studies; Anxiety disorders. Neuroses; Australia - epidemiology; Biological and medical sciences; Effect Modifier, Epidemiologic; Epidemiologic Methods; Female; Humans; interviews; Logistic Models; Male; Medical sciences; post-traumatic; Post-traumatic stress disorder; Prevalence; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Reproducibility of Results; Sex Factors; stress disorders; Stress Disorders, Post-Traumatic - diagnosis; Stress Disorders, Post-Traumatic - epidemiology; Surveys and Questionnaires; Veterans; United States; North America; America; Australia; Human; Logistic regression; Posttraumatic syndrome; Methodology; Reproducibility; Anxiety disorder; War; Diagnosis; Epidemiology; Public health; Interview
• ISSN: 0002-9262; 1476-6256
• DOI: 10.1093/oxfordjournals.aje.a008969

In an epidemiologic study of 641 interviewed subjects in the Australian Vietnam Veterans Health Study, three diagnoses of Vietnam combat-related posttraumatic stress disorder (PTSD) were obtained: lifetime prevalence using a variant of the Diagnostic Interview Schedule and lifetime and current (1-month) PTSD prevalence using the Standardized Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, Third Revision. Prevalence estimates using the Standardized Clinical Interview varied according to interviewer characteristics (female vs. male, clinician vs. nonclinician) but not for the Diagnostic Interview Schedule. The authors use a simple variant of logistic regression to distill estimates of two informative parameters characterizing interviewers' judgments: severity threshold (related to the individual interviewers' criterion of “case-ness”) and reliability (related to degree of classification error of the individual interviewers). Examination of these estimates shows that female clinicians adopted lower severity thresholds for diagnosis of PTSD than other interviewers and hence had higher prevalence estimates while being relatively reliable in their judgments. Examination also shows that nonclinician interviewers can perform at least as reliably as clinicians. The Diagnostic Interview Schedule measure of PTSD was not moderated by these interviewer aspects. This use of threshold and reliability parameters is offered for routine use in epidemiologic field studies to examine potential interviewer effects. Am J Epidemiol 1996; 144: 589–97.