Background: Cross-cultural use of the cutoff points determined in Indo-Chinese refugees of the Hopkins Symptom Checklist-25 (HSCL-25) and the Harvard Trauma Questionnaire (HTQ) is common in refugee mental health research but it might have caused misclassifications.
Methods: We assessed the validity of the predetermined cutoff points in identifying depression and post-traumatic stress disorder (PTSD) cases among Afghan refugees, with the algorithm method as a gold standard. We estimated the prevalence of depression and PTSD, using the HSCL-25 and the HTQ with the cutoff points and the algorithm method, and calculated sensitivity, specificity, positive and negative predictive values of the cutoff points.
Results: Nine in ten PTSD cases/non-cases were correctly identified as cases/non-cases, and nine in ten respondents classified as PTSD cases/non-cases were actually cases/non-cases. In contrast, only one in three non-depression cases was correctly identified as a non-case, and three in five respondents who were classified as depression cases was actually a case. The prevalence of depression was estimated to be 86% with the cutoff points and 53% with the algorithm method, and that of PTSD 46% and 44%, respectively.
Conclusions: The cutoff point approach might have low specificity and positive predictive value particularly for depression in our study. Cross-cultural use of the scale cutoff points determined in one cultural group to another needs to be reconsidered.