Diagnostic discriminative accuracy and cut-off values of the Arabic-language PHQ-9 in a treatment-seeking mental health sample.

THEORETICAL BACKGROUND: The PHQ-9 is a widely used international screening instrument for depressive disorders, but optimal cut-off values vary depending on population and geographical region. RESEARCH QUESTION: This study aims to evaluate the psychometric properties and diagnostic accuracy of the Arabic PHQ-9 and identify the threshold with the best discrimination of current major depressive episode (MDE). METHOD: In this prospective diagnostic accuracy study, 2298 individuals were included as a convenience sample as part of an intake screening for an Arabic-language therapy project. Participants completed questionnaires and underwent a telephone-based SCID-5-CV interview, which served as the reference standard; the PHQ-9 served as the index test. Psychometric properties were assessed using EFA and CFA, and diagnostic accuracy was evaluated using ROC analyses. RESULTS: Of the 2298 participants included in the analyses, 1967 met SCID-5-CV criteria for a current MDE, while 331 did not. The psychometric evaluation yielded satisfactory values overall. The AUC was 0.71 (95% CI = 0.69-0.75). The highest sensitivity was observed at a cut-off of 10 (Se = 0.93, Sp = 0.34), while the Youden Index indicated that a cut-off of 14 provided the best balance between sensitivity (0.76) and specificity (0.56). CONCLUSION: Given that high sensitivity is central in clinical studies, the Arabic PHQ-9 is suitable as a first step in a stepped screening procedure, but not for diagnostic decision-making. Cut-off values from other linguistic versions cannot be automatically transferred and must instead be validated specifically for each language version. REGISTRATION: DRKS00016652.