A study of diagnostic accuracy of the Florida Obsessive-Compulsive Inventory - Thai Version (FOCI-T)

Background: The Florida Obsessive-Compulsive Inventory (FOCI) is a self-reported measure to assess the symptoms and severity of obsessive-compulsive disorder (OCD), which can be completed in five minutes. Although preliminary studies have shown its good psychometric properties, the study of receiver operating characteristics (ROC) to use it as a screening tool has never been reported elsewhere. This study aimed to use the ROC analysis to determine the optimal cut-off score of the Thai version of the FOCI (FOCI-T). Methods: A total of 197 participants completed the FOCI-T, the Patient Health Questionnaire (PHQ-9), and the Pictorial Thai Quality of Life (PTQL), and they were also interviewed with the Mini International Neuropsychiatric Interview (MINI) for their diagnosis. The ROC analyses of the FOCI-T Severity Scores were computed to determine the best cut-off score. Results:When the Thai version of the MINI was used in the interview, it was found that 38 participants were diagnosed with OCD, 43 participants were non-OCD, and 116 participants were healthy adults. The ROC analyses indicated that the FOCI-T Severity Scale could significantly distinguish OCD patients from non-OCD patients and healthy adults. The area under curve was estimated to be 0.945 (95%CI = 0.903-0.972). A cut-off score of ≥5 provided the best sensitivity (0.92) and specificity (0.82). Conclusion: The Thai version of the Florida Obsessive-Compulsive Inventory has demonstrated its good predictive abilities, so it could be used as a brief screening tool to detect obsessive-compulsive disorder patients with high sensitivity and specificity.